From: Peter Johnson <peter@tortall.net>
Date: Mon, 5 Nov 2001 05:49:19 +0000 (-0000)
Subject: Split x86-specific stuff away from bytecode.
X-Git-Tag: v0.1.0~214
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=f58d7cb0931d5aed699c1cc20bceaa24531b2ec4;p=yasm

Split x86-specific stuff away from bytecode.

svn path=/trunk/yasm/; revision=316
---

diff --git a/frontends/yasm/yasm.c b/frontends/yasm/yasm.c
index 0b4d711f..de7a27b9 100644
--- a/frontends/yasm/yasm.c
+++ b/frontends/yasm/yasm.c
@@ -41,6 +41,8 @@ RCSID("$IdPath$");
 #include "preproc.h"
 #include "parser.h"
 
+#include "arch.h"
+
 
 #ifndef countof
 #define countof(x,y)	(sizeof(x)/sizeof(y))
@@ -110,8 +112,11 @@ main(int argc, char *argv[])
 	switch_filename("<STDIN>");
     }
 
+    /* Set x86 as the architecture */
+    cur_arch = &x86_arch;
+
     /* Get initial BITS setting from object format */
-    mode_bits = dbg_objfmt.default_mode_bits;
+    x86_mode_bits = dbg_objfmt.default_mode_bits;
 
     sections = nasm_parser.do_parse(&nasm_parser, &dbg_objfmt, in);
 
diff --git a/libyasm/arch.c b/libyasm/arch.c
new file mode 100644
index 00000000..5cbe3591
--- /dev/null
+++ b/libyasm/arch.c
@@ -0,0 +1,29 @@
+/* $IdPath$
+ * Architecture interface
+ *
+ *  Copyright (C) 2001  Peter Johnson
+ *
+ *  This file is part of YASM.
+ *
+ *  YASM is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  YASM is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+#include "util.h"
+
+#include "bytecode.h"
+
+#include "arch.h"
+
+arch *cur_arch;
+
diff --git a/libyasm/arch.h b/libyasm/arch.h
index f1ed7268..b614aca4 100644
--- a/libyasm/arch.h
+++ b/libyasm/arch.h
@@ -28,9 +28,24 @@ struct arch {
 
     /* keyword used to select architecture */
     const char *keyword;
+
+    struct {
+	/* Maximum used bytecode type value+1.  Should be set to
+	 * BYTECODE_TYPE_BASE if no additional bytecode types are defined by
+	 * the architecture.
+	 */
+	const int type_max;
+
+	void (*bc_delete) (bytecode *bc);
+	void (*bc_print) (const bytecode *bc);
+	void (*bc_parser_finalize) (bytecode *bc);
+    } bc;
 };
 
 /* Available architectures */
+#include "arch/x86/x86arch.h"
 extern arch x86_arch;
 
+extern arch *cur_arch;
+
 #endif
diff --git a/libyasm/bc-int.h b/libyasm/bc-int.h
new file mode 100644
index 00000000..f992c465
--- /dev/null
+++ b/libyasm/bc-int.h
@@ -0,0 +1,71 @@
+/* $IdPath$
+ * Bytecode internal structures header file
+ *
+ *  Copyright (C) 2001  Peter Johnson
+ *
+ *  This file is part of YASM.
+ *
+ *  YASM is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  YASM is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+#ifndef YASM_BC_INT_H
+#define YASM_BC_INT_H
+
+struct effaddr {
+    expr *disp;			/* address displacement */
+    unsigned char len;		/* length of disp (in bytes), 0 if unknown,
+				 * 0xff if unknown and required to be >0.
+				 */
+    unsigned char nosplit;	/* 1 if reg*2 should not be split into
+				   reg+reg. (0 if not) */
+
+    /* architecture-dependent data may be appended */
+};
+#define ea_get_data(x)		(void *)(((char *)x)+sizeof(effaddr))
+#define ea_get_const_data(x)	(const void *)(((const char *)x)+sizeof(effaddr))
+
+struct immval {
+    expr *val;
+
+    unsigned char len;		/* length of val (in bytes), 0 if unknown */
+    unsigned char isneg;	/* the value has been explicitly negated */
+
+    unsigned char f_len;	/* final imm length */
+    unsigned char f_sign;	/* 1 if final imm should be signed */
+};
+
+struct bytecode {
+    STAILQ_ENTRY(bytecode) link;
+
+    bytecode_type type;
+
+    expr *multiple;		/* number of times bytecode is repeated,
+				   NULL=1 */
+
+    unsigned long len;		/* total length of entire bytecode (including
+				   multiple copies), 0 if unknown */
+
+    /* where it came from */
+    const char *filename;
+    unsigned int lineno;
+
+    /* other assembler state info */
+    unsigned long offset;	/* 0 if unknown */
+
+    /* architecture-dependent data may be appended */
+};
+#define bc_get_data(x)		(void *)(((char *)x)+sizeof(bytecode))
+#define bc_get_const_data(x)	(const void *)(((const char *)x)+sizeof(bytecode))
+
+#endif
diff --git a/libyasm/bytecode.c b/libyasm/bytecode.c
index 407f01ec..6dae585d 100644
--- a/libyasm/bytecode.c
+++ b/libyasm/bytecode.c
@@ -29,40 +29,10 @@ RCSID("$IdPath$");
 
 #include "bytecode.h"
 
+#include "arch.h"
 
-struct effaddr {
-    expr *disp;			/* address displacement */
-    unsigned char len;		/* length of disp (in bytes), 0 if unknown,
-				 * 0xff if unknown and required to be >0.
-				 */
+#include "bc-int.h"
 
-    unsigned char segment;	/* segment override, 0 if none */
-
-    /* How the spare (register) bits in Mod/RM are handled:
-     * Even if valid_modrm=0, the spare bits are still valid (don't overwrite!)
-     * They're set in bytecode_new_insn().
-     */
-    unsigned char modrm;
-    unsigned char valid_modrm;	/* 1 if Mod/RM byte currently valid, 0 if not */
-    unsigned char need_modrm;	/* 1 if Mod/RM byte needed, 0 if not */
-
-    unsigned char sib;
-    unsigned char valid_sib;	/* 1 if SIB byte currently valid, 0 if not */
-    unsigned char need_sib;	/* 1 if SIB byte needed, 0 if not,
-				   0xff if unknown */
-    unsigned char nosplit;	/* 1 if reg*2 should not be split into
-				   reg+reg. (0 if not) */
-};
-
-struct immval {
-    expr *val;
-
-    unsigned char len;		/* length of val (in bytes), 0 if unknown */
-    unsigned char isneg;	/* the value has been explicitly negated */
-
-    unsigned char f_len;	/* final imm length */
-    unsigned char f_sign;	/* 1 if final imm should be signed */
-};
 
 struct dataval {
     STAILQ_ENTRY(dataval) link;
@@ -75,158 +45,25 @@ struct dataval {
     } data;
 };
 
-struct bytecode {
-    STAILQ_ENTRY(bytecode) link;
-
-    enum { BC_EMPTY, BC_INSN, BC_JMPREL, BC_DATA, BC_RESERVE } type;
-
-    /* This union has been somewhat tweaked to get it as small as possible
-     * on the 4-byte-aligned x86 architecture (without resorting to
-     * bitfields).  In particular, insn and jmprel are the largest structures
-     * in the union, and are also the same size (after padding).  jmprel
-     * can have another unsigned char added to the end without affecting
-     * its size.
-     *
-     * Don't worry about this too much, but keep it in mind when changing
-     * this structure.  We care about the size of bytecode in particular
-     * because it accounts for the majority of the memory usage in the
-     * assembler when assembling a large file.
-     */
-    union {
-	struct {
-	    effaddr *ea;	/* effective address */
-
-	    immval *imm;	/* immediate or relative value */
-
-	    unsigned char opcode[3];	/* opcode */
-	    unsigned char opcode_len;
-
-	    unsigned char addrsize;	/* 0 or =mode_bits => no override */
-	    unsigned char opersize;	/* 0 indicates no override */
-	    unsigned char lockrep_pre;	/* 0 indicates no prefix */
-
-	    /* HACK, but a space-saving one: shift opcodes have an immediate
-	     * form and a ,1 form (with no immediate).  In the parser, we
-	     * set this and opcode_len=1, but store the ,1 version in the
-	     * second byte of the opcode array.  We then choose between the
-	     * two versions once we know the actual value of imm (because we
-	     * don't know it in the parser module).
-	     *
-	     * A override to force the imm version should just leave this at
-	     * 0.  Then later code won't know the ,1 version even exists.
-	     * TODO: Figure out how this affects CPU flags processing.
-	     *
-	     * Call SetInsnShiftFlag() to set this flag to 1.
-	     */
-	    unsigned char shift_op;
-	} insn;
-	struct {
-	    expr *target;		/* target location */
-
-	    struct {
-		unsigned char opcode[3];
-		unsigned char opcode_len;   /* 0 = no opc for this version */
-	    } shortop, nearop;
-
-	    /* which opcode are we using? */
-	    /* The *FORCED forms are specified in the source as such */
-	    jmprel_opcode_sel op_sel;
-
-	    unsigned char addrsize;	/* 0 or =mode_bits => no override */
-	    unsigned char opersize;	/* 0 indicates no override */
-	    unsigned char lockrep_pre;	/* 0 indicates no prefix */
-	} jmprel;
-	struct {
-	    /* non-converted data (linked list) */
-	    datavalhead datahead;
-
-	    /* final (converted) size of each element (in bytes) */
-	    unsigned char size;
-	} data;
-	struct {
-	    expr *numitems;		/* number of items to reserve */
-	    unsigned char itemsize;	/* size of each item (in bytes) */
-	} reserve;
-    } data;
+typedef struct bytecode_data {
+    /* non-converted data (linked list) */
+    datavalhead datahead;
 
-    expr *multiple;		/* number of times bytecode is repeated,
-				   NULL=1 */
+    /* final (converted) size of each element (in bytes) */
+    unsigned char size;
+} bytecode_data;
 
-    unsigned long len;		/* total length of entire bytecode (including
-				   multiple copies), 0 if unknown */
-
-    /* where it came from */
-    const char *filename;
-    unsigned int lineno;
-
-    /* other assembler state info */
-    unsigned long offset;	/* 0 if unknown */
-    unsigned char mode_bits;
-};
+typedef struct bytecode_reserve {
+    expr *numitems;		/* number of items to reserve */
+    unsigned char itemsize;	/* size of each item (in bytes) */
+} bytecode_reserve;
 
 /* Static structures for when NULL is passed to conversion functions. */
 /*  for Convert*ToBytes() */
 unsigned char bytes_static[16];
 
-static bytecode *bytecode_new_common(void);
-
-effaddr *
-effaddr_new_reg(unsigned long reg)
-{
-    effaddr *ea = xmalloc(sizeof(effaddr));
-
-    ea->disp = (expr *)NULL;
-    ea->len = 0;
-    ea->segment = 0;
-    ea->modrm = 0xC0 | (reg & 0x07);	/* Mod=11, R/M=Reg, Reg=0 */
-    ea->valid_modrm = 1;
-    ea->need_modrm = 1;
-    ea->valid_sib = 0;
-    ea->need_sib = 0;
-    ea->nosplit = 0;
-
-    return ea;
-}
-
-effaddr *
-effaddr_new_expr(expr *expr_ptr)
-{
-    effaddr *ea = xmalloc(sizeof(effaddr));
-
-    ea->disp = expr_ptr;
-    ea->len = 0;
-    ea->segment = 0;
-    ea->modrm = 0;
-    ea->valid_modrm = 0;
-    ea->need_modrm = 1;
-    ea->valid_sib = 0;
-    ea->need_sib = 0xff;    /* we won't know until we know more about expr and
-			       the BITS/address override setting */
-    ea->nosplit = 0;
-
-    return ea;
-}
-
-effaddr *
-effaddr_new_imm(immval *im_ptr, unsigned char im_len)
-{
-    effaddr *ea = xmalloc(sizeof(effaddr));
-
-    ea->disp = im_ptr->val;
-    ea->len = im_len;
-    ea->segment = 0;
-    ea->modrm = 0;
-    ea->valid_modrm = 0;
-    ea->need_modrm = 0;
-    ea->valid_sib = 0;
-    ea->need_sib = 0;
-    ea->nosplit = 0;
-
-    return ea;
-}
-
 immval *
-immval_new_int(unsigned long int_val)
+imm_new_int(unsigned long int_val)
 {
     immval *im = xmalloc(sizeof(immval));
 
@@ -245,7 +82,7 @@ immval_new_int(unsigned long int_val)
 }
 
 immval *
-immval_new_expr(expr *expr_ptr)
+imm_new_expr(expr *expr_ptr)
 {
     immval *im = xmalloc(sizeof(immval));
 
@@ -257,19 +94,7 @@ immval_new_expr(expr *expr_ptr)
 }
 
 void
-SetEASegment(effaddr *ptr, unsigned char segment)
-{
-    if (!ptr)
-	return;
-
-    if (segment != 0 && ptr->segment != 0)
-	Warning(_("multiple segment overrides, using leftmost"));
-
-    ptr->segment = segment;
-}
-
-void
-SetEALen(effaddr *ptr, unsigned char len)
+ea_set_len(effaddr *ptr, unsigned char len)
 {
     if (!ptr)
 	return;
@@ -282,7 +107,7 @@ SetEALen(effaddr *ptr, unsigned char len)
 }
 
 void
-SetEANosplit(effaddr *ptr, unsigned char nosplit)
+ea_set_nosplit(effaddr *ptr, unsigned char nosplit)
 {
     if (!ptr)
 	return;
@@ -290,108 +115,8 @@ SetEANosplit(effaddr *ptr, unsigned char nosplit)
     ptr->nosplit = nosplit;
 }
 
-effaddr *
-GetInsnEA(bytecode *bc)
-{
-    if (!bc)
-	return NULL;
-
-    if (bc->type != BC_INSN)
-	InternalError(_("Trying to get EA of non-instruction"));
-
-    return bc->data.insn.ea;
-}
-
 void
-SetInsnOperSizeOverride(bytecode *bc, unsigned char opersize)
-{
-    if (!bc)
-	return;
-
-    switch (bc->type) {
-	case BC_INSN:
-	    bc->data.insn.opersize = opersize;
-	    break;
-	case BC_JMPREL:
-	    bc->data.jmprel.opersize = opersize;
-	    break;
-	default:
-	    InternalError(_("OperSize override applied to non-instruction"));
-	    return;
-    }
-}
-
-void
-SetInsnAddrSizeOverride(bytecode *bc, unsigned char addrsize)
-{
-    if (!bc)
-	return;
-
-    switch (bc->type) {
-	case BC_INSN:
-	    bc->data.insn.addrsize = addrsize;
-	    break;
-	case BC_JMPREL:
-	    bc->data.jmprel.addrsize = addrsize;
-	    break;
-	default:
-	    InternalError(_("AddrSize override applied to non-instruction"));
-	    return;
-    }
-}
-
-void
-SetInsnLockRepPrefix(bytecode *bc, unsigned char prefix)
-{
-    unsigned char *lockrep_pre = (unsigned char *)NULL;
-
-    if (!bc)
-	return;
-
-    switch (bc->type) {
-	case BC_INSN:
-	    lockrep_pre = &bc->data.insn.lockrep_pre;
-	    break;
-	case BC_JMPREL:
-	    lockrep_pre = &bc->data.jmprel.lockrep_pre;
-	    break;
-	default:
-	    InternalError(_("LockRep prefix applied to non-instruction"));
-	    return;
-    }
-
-    if (*lockrep_pre != 0)
-	Warning(_("multiple LOCK or REP prefixes, using leftmost"));
-
-    *lockrep_pre = prefix;
-}
-
-void
-SetInsnShiftFlag(bytecode *bc)
-{
-    if (!bc)
-	return;
-
-    if (bc->type != BC_INSN)
-	InternalError(_("Attempted to set shift flag on non-instruction"));
-
-    bc->data.insn.shift_op = 1;
-}
-
-void
-SetOpcodeSel(jmprel_opcode_sel *old_sel, jmprel_opcode_sel new_sel)
-{
-    if (!old_sel)
-	return;
-
-    if (new_sel != JR_NONE && ((*old_sel == JR_SHORT_FORCED) ||
-			       (*old_sel == JR_NEAR_FORCED)))
-	Warning(_("multiple SHORT or NEAR specifiers, using leftmost"));
-    *old_sel = new_sel;
-}
-
-void
-SetBCMultiple(bytecode *bc, expr *e)
+bc_set_multiple(bytecode *bc, expr *e)
 {
     if (bc->multiple)
 	bc->multiple = expr_new_tree(bc->multiple, EXPR_MUL, e);
@@ -399,10 +124,12 @@ SetBCMultiple(bytecode *bc, expr *e)
 	bc->multiple = e;
 }
 
-static bytecode *
-bytecode_new_common(void)
+bytecode *
+bc_new_common(bytecode_type type, size_t datasize)
 {
-    bytecode *bc = xmalloc(sizeof(bytecode));
+    bytecode *bc = xmalloc(sizeof(bytecode)+datasize);
+
+    bc->type = type;
 
     bc->multiple = (expr *)NULL;
     bc->len = 0;
@@ -411,146 +138,59 @@ bytecode_new_common(void)
     bc->lineno = line_number;
 
     bc->offset = 0;
-    bc->mode_bits = mode_bits;
 
     return bc;
 }
 
 bytecode *
-bytecode_new_insn(unsigned char  opersize,
-		  unsigned char  opcode_len,
-		  unsigned char  op0,
-		  unsigned char  op1,
-		  unsigned char  op2,
-		  effaddr       *ea_ptr,
-		  unsigned char  spare,
-		  immval        *im_ptr,
-		  unsigned char  im_len,
-		  unsigned char  im_sign)
+bc_new_data(datavalhead *datahead, unsigned long size)
 {
-    bytecode *bc = bytecode_new_common();
+    bytecode *bc = bc_new_common(BC_DATA, sizeof(bytecode_data));
+    bytecode_data *data = bc_get_data(bc);
 
-    bc->type = BC_INSN;
-
-    bc->data.insn.ea = ea_ptr;
-    if (ea_ptr) {
-	bc->data.insn.ea->modrm &= 0xC7;	/* zero spare/reg bits */
-	bc->data.insn.ea->modrm |= (spare << 3) & 0x38;	/* plug in provided bits */
-    }
-
-    bc->data.insn.imm = im_ptr;
-    if (im_ptr) {
-	bc->data.insn.imm->f_sign = im_sign;
-	bc->data.insn.imm->f_len = im_len;
-    }
-
-    bc->data.insn.opcode[0] = op0;
-    bc->data.insn.opcode[1] = op1;
-    bc->data.insn.opcode[2] = op2;
-    bc->data.insn.opcode_len = opcode_len;
-
-    bc->data.insn.addrsize = 0;
-    bc->data.insn.opersize = opersize;
-    bc->data.insn.lockrep_pre = 0;
-    bc->data.insn.shift_op = 0;
-
-    return bc;
-}
-
-bytecode *
-bytecode_new_jmprel(targetval     *target,
-		    unsigned char  short_opcode_len,
-		    unsigned char  short_op0,
-		    unsigned char  short_op1,
-		    unsigned char  short_op2,
-		    unsigned char  near_opcode_len,
-		    unsigned char  near_op0,
-		    unsigned char  near_op1,
-		    unsigned char  near_op2,
-		    unsigned char  addrsize)
-{
-    bytecode *bc = bytecode_new_common();
-
-    bc->type = BC_JMPREL;
-
-    bc->data.jmprel.target = target->val;
-    bc->data.jmprel.op_sel = target->op_sel;
-
-    if ((target->op_sel == JR_SHORT_FORCED) && (near_opcode_len == 0))
-	Error(_("no SHORT form of that jump instruction exists"));
-    if ((target->op_sel == JR_NEAR_FORCED) && (short_opcode_len == 0))
-	Error(_("no NEAR form of that jump instruction exists"));
-
-    bc->data.jmprel.shortop.opcode[0] = short_op0;
-    bc->data.jmprel.shortop.opcode[1] = short_op1;
-    bc->data.jmprel.shortop.opcode[2] = short_op2;
-    bc->data.jmprel.shortop.opcode_len = short_opcode_len;
-
-    bc->data.jmprel.nearop.opcode[0] = near_op0;
-    bc->data.jmprel.nearop.opcode[1] = near_op1;
-    bc->data.jmprel.nearop.opcode[2] = near_op2;
-    bc->data.jmprel.nearop.opcode_len = near_opcode_len;
-
-    bc->data.jmprel.addrsize = addrsize;
-    bc->data.jmprel.opersize = 0;
-    bc->data.jmprel.lockrep_pre = 0;
+    data->datahead = *datahead;
+    data->size = size;
 
     return bc;
 }
 
 bytecode *
-bytecode_new_data(datavalhead *datahead, unsigned long size)
+bc_new_reserve(expr *numitems, unsigned long itemsize)
 {
-    bytecode *bc = bytecode_new_common();
-
-    bc->type = BC_DATA;
+    bytecode *bc = bc_new_common(BC_RESERVE, sizeof(bytecode_reserve));
+    bytecode_reserve *reserve = bc_get_data(bc);
 
-    bc->data.data.datahead = *datahead;
-    bc->data.data.size = size;
-
-    return bc;
-}
-
-bytecode *
-bytecode_new_reserve(expr *numitems, unsigned long itemsize)
-{
-    bytecode *bc = bytecode_new_common();
-
-    bc->type = BC_RESERVE;
-
-    bc->data.reserve.numitems = numitems;
-    bc->data.reserve.itemsize = itemsize;
+    reserve->numitems = numitems;
+    reserve->itemsize = itemsize;
 
     return bc;
 }
 
 void
-bytecode_delete(bytecode *bc)
+bc_delete(bytecode *bc)
 {
+    bytecode_data *data;
+    bytecode_reserve *reserve;
+
     if (!bc)
 	return;
 
     switch (bc->type) {
 	case BC_EMPTY:
 	    break;
-	case BC_INSN:
-	    if (bc->data.insn.ea) {
-		expr_delete(bc->data.insn.ea->disp);
-		xfree(bc->data.insn.ea);
-	    }
-	    if (bc->data.insn.imm) {
-		expr_delete(bc->data.insn.imm->val);
-		xfree(bc->data.insn.imm);
-	    }
-	    break;
-	case BC_JMPREL:
-	    expr_delete(bc->data.jmprel.target);
-	    break;
 	case BC_DATA:
-	    datavals_delete(&bc->data.data.datahead);
+	    data = bc_get_data(bc);
+	    dvs_delete(&data->datahead);
 	    break;
 	case BC_RESERVE:
-	    expr_delete(bc->data.reserve.numitems);
+	    reserve = bc_get_data(bc);
+	    expr_delete(reserve->numitems);
+	    break;
+	default:
+	    if (bc->type < cur_arch->bc.type_max)
+		cur_arch->bc.bc_delete(bc);
+	    else
+		InternalError(_("Unknown bytecode type"));
 	    break;
     }
 
@@ -559,131 +199,43 @@ bytecode_delete(bytecode *bc)
 }
 
 int
-bytecode_get_offset(section *sect, bytecode *bc, unsigned long *ret_val)
+bc_get_offset(section *sect, bytecode *bc, unsigned long *ret_val)
 {
     return 0;	/* TODO */
 }
 
 void
-bytecode_print(const bytecode *bc)
+bc_print(const bytecode *bc)
 {
+    const bytecode_data *data;
+    const bytecode_reserve *reserve;
+
     switch (bc->type) {
 	case BC_EMPTY:
 	    printf("_Empty_\n");
 	    break;
-	case BC_INSN:
-	    printf("_Instruction_\n");
-	    printf("Effective Address:");
-	    if (!bc->data.insn.ea)
-		printf(" (nil)\n");
-	    else {
-		printf("\n Disp=");
-		if (bc->data.insn.ea->disp)
-		    expr_print(bc->data.insn.ea->disp);
-		else
-		    printf("(nil)");
-		printf("\n");
-		printf(" Len=%u SegmentOv=%02x NoSplit=%u\n",
-		       (unsigned int)bc->data.insn.ea->len,
-		       (unsigned int)bc->data.insn.ea->segment,
-		       (unsigned int)bc->data.insn.ea->nosplit);
-		printf(" ModRM=%03o ValidRM=%u NeedRM=%u\n",
-		       (unsigned int)bc->data.insn.ea->modrm,
-		       (unsigned int)bc->data.insn.ea->valid_modrm,
-		       (unsigned int)bc->data.insn.ea->need_modrm);
-		printf(" SIB=%03o ValidSIB=%u NeedSIB=%u\n",
-		       (unsigned int)bc->data.insn.ea->sib,
-		       (unsigned int)bc->data.insn.ea->valid_sib,
-		       (unsigned int)bc->data.insn.ea->need_sib);
-	    }
-	    printf("Immediate Value:");
-	    if (!bc->data.insn.imm)
-		printf(" (nil)\n");
-	    else {
-		printf("\n Val=");
-		expr_print(bc->data.insn.imm->val);
-		printf("\n");
-		printf(" Len=%u, IsNeg=%u\n",
-		       (unsigned int)bc->data.insn.imm->len,
-		       (unsigned int)bc->data.insn.imm->isneg);
-		printf(" FLen=%u, FSign=%u\n",
-		       (unsigned int)bc->data.insn.imm->f_len,
-		       (unsigned int)bc->data.insn.imm->f_sign);
-	    }
-	    printf("Opcode: %02x %02x %02x OpLen=%u\n",
-		   (unsigned int)bc->data.insn.opcode[0],
-		   (unsigned int)bc->data.insn.opcode[1],
-		   (unsigned int)bc->data.insn.opcode[2],
-		   (unsigned int)bc->data.insn.opcode_len);
-	    printf("AddrSize=%u OperSize=%u LockRepPre=%02x ShiftOp=%u\n",
-		   (unsigned int)bc->data.insn.addrsize,
-		   (unsigned int)bc->data.insn.opersize,
-		   (unsigned int)bc->data.insn.lockrep_pre,
-		   (unsigned int)bc->data.insn.shift_op);
-	    break;
-	case BC_JMPREL:
-	    printf("_Relative Jump_\n");
-	    printf("Target=");
-	    expr_print(bc->data.jmprel.target);
-	    printf("\nShort Form:\n");
-	    if (!bc->data.jmprel.shortop.opcode_len == 0)
-		printf(" None\n");
-	    else
-		printf(" Opcode: %02x %02x %02x OpLen=%u\n",
-		       (unsigned int)bc->data.jmprel.shortop.opcode[0],
-		       (unsigned int)bc->data.jmprel.shortop.opcode[1],
-		       (unsigned int)bc->data.jmprel.shortop.opcode[2],
-		       (unsigned int)bc->data.jmprel.shortop.opcode_len);
-	    if (!bc->data.jmprel.nearop.opcode_len == 0)
-		printf(" None\n");
-	    else
-		printf(" Opcode: %02x %02x %02x OpLen=%u\n",
-		       (unsigned int)bc->data.jmprel.nearop.opcode[0],
-		       (unsigned int)bc->data.jmprel.nearop.opcode[1],
-		       (unsigned int)bc->data.jmprel.nearop.opcode[2],
-		       (unsigned int)bc->data.jmprel.nearop.opcode_len);
-	    printf("OpSel=");
-	    switch (bc->data.jmprel.op_sel) {
-		case JR_NONE:
-		    printf("None");
-		    break;
-		case JR_SHORT:
-		    printf("Short");
-		    break;
-		case JR_NEAR:
-		    printf("Near");
-		    break;
-		case JR_SHORT_FORCED:
-		    printf("Forced Short");
-		    break;
-		case JR_NEAR_FORCED:
-		    printf("Forced Near");
-		    break;
-		default:
-		    printf("UNKNOWN!!");
-		    break;
-	    }
-	    printf("\nAddrSize=%u OperSize=%u LockRepPre=%02x\n",
-		   (unsigned int)bc->data.jmprel.addrsize,
-		   (unsigned int)bc->data.jmprel.opersize,
-		   (unsigned int)bc->data.jmprel.lockrep_pre);
-	    break;
 	case BC_DATA:
+	    data = bc_get_const_data(bc);
 	    printf("_Data_\n");
 	    printf("Final Element Size=%u\n",
-		   (unsigned int)bc->data.data.size);
+		   (unsigned int)data->size);
 	    printf("Elements:\n");
-	    datavals_print(&bc->data.data.datahead);
+	    dvs_print(&data->datahead);
 	    break;
 	case BC_RESERVE:
+	    reserve = bc_get_const_data(bc);
 	    printf("_Reserve_\n");
 	    printf("Num Items=");
-	    expr_print(bc->data.reserve.numitems);
+	    expr_print(reserve->numitems);
 	    printf("\nItem Size=%u\n",
-		   (unsigned int)bc->data.reserve.itemsize);
+		   (unsigned int)reserve->itemsize);
 	    break;
 	default:
-	    printf("_Unknown_\n");
+	    if (bc->type < cur_arch->bc.type_max)
+		cur_arch->bc.bc_print(bc);
+	    else
+		printf("_Unknown_\n");
+	    break;
     }
     printf("Multiple=");
     if (!bc->multiple)
@@ -694,95 +246,42 @@ bytecode_print(const bytecode *bc)
     printf("Length=%lu\n", bc->len);
     printf("Filename=\"%s\" Line Number=%u\n",
 	   bc->filename ? bc->filename : "<UNKNOWN>", bc->lineno);
-    printf("Offset=%lx BITS=%u\n", bc->offset, bc->mode_bits);
-}
-
-static void
-bytecode_parser_finalize_insn(bytecode *bc)
-{
-    effaddr *ea = bc->data.insn.ea;
-    immval *imm = bc->data.insn.imm;
-
-    if (ea) {
-	if ((ea->disp) && ((!ea->valid_sib && ea->need_sib) ||
-			   (!ea->valid_modrm && ea->need_modrm))) {
-	    /* First expand equ's */
-	    expr_expand_equ(ea->disp);
-
-	    /* Check validity of effective address and calc R/M bits of
-	     * Mod/RM byte and SIB byte.  We won't know the Mod field
-	     * of the Mod/RM byte until we know more about the
-	     * displacement.
-	     */
-	    if (!expr_checkea(&ea->disp, &bc->data.insn.addrsize,
-			      bc->mode_bits, ea->nosplit, &ea->len, &ea->modrm,
-			      &ea->valid_modrm, &ea->need_modrm, &ea->sib,
-			      &ea->valid_sib, &ea->need_sib))
-		return;	    /* failed, don't bother checking rest of insn */
-	}
-    }
-
-    if (imm) {
-	const intnum *num;
-
-	if (imm->val) {
-	    expr_expand_equ(imm->val);
-	    expr_simplify(imm->val);
-	}
-	/* TODO: check imm f_len vs. len? */
-
-	/* Handle shift_op special-casing */
-	if (bc->data.insn.shift_op && (num = expr_get_intnum(&imm->val))) {
-	    if (intnum_get_uint(num) == 1) {
-		/* Use ,1 form: first copy ,1 opcode. */
-		bc->data.insn.opcode[0] = bc->data.insn.opcode[1];
-		/* Delete ModRM, as it's no longer needed */
-		xfree(ea);
-		bc->data.insn.ea = (effaddr *)NULL;
-		/* Delete Imm, as it's not needed */
-		expr_delete(imm->val);
-		xfree(imm);
-		bc->data.insn.imm = (immval *)NULL;
-	    }
-	    bc->data.insn.shift_op = 0;
-	}
-    }
-
-    
+    printf("Offset=%lx\n", bc->offset);
 }
 
 void
-bytecode_parser_finalize(bytecode *bc)
+bc_parser_finalize(bytecode *bc)
 {
     switch (bc->type) {
 	case BC_EMPTY:
 	    /* FIXME: delete it (probably in bytecodes_ level, not here */
 	    InternalError(_("got empty bytecode in parser_finalize"));
 	    break;
-	case BC_INSN:
-	    bytecode_parser_finalize_insn(bc);
-	    break;
 	default:
+	    if (bc->type < cur_arch->bc.type_max)
+		cur_arch->bc.bc_parser_finalize(bc);
+	    else
+		InternalError(_("Unknown bytecode type"));
 	    break;
     }
 }
 
 void
-bytecodes_delete(bytecodehead *headp)
+bcs_delete(bytecodehead *headp)
 {
     bytecode *cur, *next;
 
     cur = STAILQ_FIRST(headp);
     while (cur) {
 	next = STAILQ_NEXT(cur, link);
-	bytecode_delete(cur);
+	bc_delete(cur);
 	cur = next;
     }
     STAILQ_INIT(headp);
 }
 
 bytecode *
-bytecodes_append(bytecodehead *headp, bytecode *bc)
+bcs_append(bytecodehead *headp, bytecode *bc)
 {
     if (bc) {
 	if (bc->type != BC_EMPTY) {
@@ -796,27 +295,27 @@ bytecodes_append(bytecodehead *headp, bytecode *bc)
 }
 
 void
-bytecodes_print(const bytecodehead *headp)
+bcs_print(const bytecodehead *headp)
 {
     bytecode *cur;
 
     STAILQ_FOREACH(cur, headp, link) {
 	printf("---Next Bytecode---\n");
-	bytecode_print(cur);
+	bc_print(cur);
     }
 }
 
 void
-bytecodes_parser_finalize(bytecodehead *headp)
+bcs_parser_finalize(bytecodehead *headp)
 {
     bytecode *cur;
 
     STAILQ_FOREACH(cur, headp, link)
-	bytecode_parser_finalize(cur);
+	bc_parser_finalize(cur);
 }
 
 dataval *
-dataval_new_expr(expr *expn)
+dv_new_expr(expr *expn)
 {
     dataval *retval = xmalloc(sizeof(dataval));
 
@@ -827,7 +326,7 @@ dataval_new_expr(expr *expn)
 }
 
 dataval *
-dataval_new_string(char *str_val)
+dv_new_string(char *str_val)
 {
     dataval *retval = xmalloc(sizeof(dataval));
 
@@ -838,7 +337,7 @@ dataval_new_string(char *str_val)
 }
 
 void
-datavals_delete(datavalhead *headp)
+dvs_delete(datavalhead *headp)
 {
     dataval *cur, *next;
 
@@ -854,7 +353,7 @@ datavals_delete(datavalhead *headp)
 }
 
 dataval *
-datavals_append(datavalhead *headp, dataval *dv)
+dvs_append(datavalhead *headp, dataval *dv)
 {
     if (dv) {
 	STAILQ_INSERT_TAIL(headp, dv, link);
@@ -864,7 +363,7 @@ datavals_append(datavalhead *headp, dataval *dv)
 }
 
 void
-datavals_print(const datavalhead *head)
+dvs_print(const datavalhead *head)
 {
     dataval *cur;
 
diff --git a/libyasm/bytecode.h b/libyasm/bytecode.h
index 3683bae9..38fa3113 100644
--- a/libyasm/bytecode.h
+++ b/libyasm/bytecode.h
@@ -27,87 +27,43 @@ typedef struct immval immval;
 typedef STAILQ_HEAD(datavalhead, dataval) datavalhead;
 typedef struct dataval dataval;
 
+/* Additional types may be architecture-defined starting at
+ * BYTECODE_TYPE_BASE.
+ */
 typedef enum {
-    JR_NONE,
-    JR_SHORT,
-    JR_NEAR,
-    JR_SHORT_FORCED,
-    JR_NEAR_FORCED
-} jmprel_opcode_sel;
-
-typedef struct targetval {
-    expr *val;
-
-    jmprel_opcode_sel op_sel;
-} targetval;
-
-effaddr *effaddr_new_reg(unsigned long reg);
-effaddr *effaddr_new_imm(immval *im_ptr, unsigned char im_len);
-effaddr *effaddr_new_expr(expr *expr_ptr);
+    BC_EMPTY = 0,
+    BC_DATA,
+    BC_RESERVE
+} bytecode_type;
+#define BYTECODE_TYPE_BASE  BC_RESERVE+1
 
-immval *immval_new_int(unsigned long int_val);
-immval *immval_new_expr(expr *expr_ptr);
+immval *imm_new_int(unsigned long int_val);
+immval *imm_new_expr(expr *e);
 
-void SetEASegment(effaddr *ptr, unsigned char segment);
-void SetEALen(effaddr *ptr, unsigned char len);
-void SetEANosplit(effaddr *ptr, unsigned char nosplit);
+void ea_set_len(effaddr *ea, unsigned char len);
+void ea_set_nosplit(effaddr *ea, unsigned char nosplit);
 
-effaddr *GetInsnEA(bytecode *bc);
+void bc_set_multiple(bytecode *bc, expr *e);
 
-void SetInsnOperSizeOverride(bytecode *bc, unsigned char opersize);
-void SetInsnAddrSizeOverride(bytecode *bc, unsigned char addrsize);
-void SetInsnLockRepPrefix(bytecode *bc, unsigned char prefix);
-void SetInsnShiftFlag(bytecode *bc);
+bytecode *bc_new_common(bytecode_type type, size_t datasize);
+bytecode *bc_new_data(datavalhead *datahead, unsigned long size);
+bytecode *bc_new_reserve(expr *numitems, unsigned long itemsize);
 
-void SetOpcodeSel(jmprel_opcode_sel *old_sel, jmprel_opcode_sel new_sel);
-
-void SetBCMultiple(bytecode *bc, expr *e);
-
-/* IMPORTANT: ea_ptr and im_ptr cannot be reused or freed after calling this
- * function (it doesn't make a copy).
- */
-bytecode *bytecode_new_insn(unsigned char  opersize,
-			    unsigned char  opcode_len,
-			    unsigned char  op0,
-			    unsigned char  op1,
-			    unsigned char  op2,
-			    effaddr       *ea_ptr,
-			    unsigned char  spare,
-			    immval        *im_ptr,
-			    unsigned char  im_len,
-			    unsigned char  im_sign);
-
-/* Pass 0 for the opcode_len if that version of the opcode doesn't exist. */
-bytecode *bytecode_new_jmprel(targetval     *target,
-			      unsigned char  short_opcode_len,
-			      unsigned char  short_op0,
-			      unsigned char  short_op1,
-			      unsigned char  short_op2,
-			      unsigned char  near_opcode_len,
-			      unsigned char  near_op0,
-			      unsigned char  near_op1,
-			      unsigned char  near_op2,
-			      unsigned char  addrsize);
-
-bytecode *bytecode_new_data(datavalhead *datahead, unsigned long size);
-
-bytecode *bytecode_new_reserve(expr *numitems, unsigned long itemsize);
-
-void bytecode_delete(bytecode *bc);
+void bc_delete(bytecode *bc);
 
 /* Gets the offset of the bytecode specified by bc if possible.
  * Return value is IF POSSIBLE, not the value.
  */
-int bytecode_get_offset(section *sect, bytecode *bc, unsigned long *ret_val);
+int bc_get_offset(section *sect, bytecode *bc, unsigned long *ret_val);
 
-void bytecode_print(const bytecode *bc);
+void bc_print(const bytecode *bc);
 
-void bytecode_parser_finalize(bytecode *bc);
+void bc_parser_finalize(bytecode *bc);
 
 /* void bytecodes_initialize(bytecodehead *headp); */
 #define	bytecodes_initialize(headp)	STAILQ_INIT(headp)
 
-void bytecodes_delete(bytecodehead *headp);
+void bcs_delete(bytecodehead *headp);
 
 /* Adds bc to the list of bytecodes headp.
  * NOTE: Does not make a copy of bc; so don't pass this function
@@ -115,20 +71,20 @@ void bytecodes_delete(bytecodehead *headp);
  * this function.  If bc was actually appended (it wasn't NULL or empty),
  * then returns bc, otherwise returns NULL.
  */
-bytecode *bytecodes_append(bytecodehead *headp, bytecode *bc);
+bytecode *bcs_append(bytecodehead *headp, bytecode *bc);
 
-void bytecodes_print(const bytecodehead *headp);
+void bcs_print(const bytecodehead *headp);
 
-void bytecodes_parser_finalize(bytecodehead *headp);
+void bcs_parser_finalize(bytecodehead *headp);
 
-dataval *dataval_new_expr(expr *expn);
-dataval *dataval_new_float(floatnum *flt);
-dataval *dataval_new_string(char *str_val);
+dataval *dv_new_expr(expr *expn);
+dataval *dv_new_float(floatnum *flt);
+dataval *dv_new_string(char *str_val);
 
-/* void datavals_initialize(datavalhead *headp); */
-#define	datavals_initialize(headp)	STAILQ_INIT(headp)
+/* void dvs_initialize(datavalhead *headp); */
+#define	dvs_initialize(headp)	STAILQ_INIT(headp)
 
-void datavals_delete(datavalhead *headp);
+void dvs_delete(datavalhead *headp);
 
 /* Adds dv to the list of datavals headp.
  * NOTE: Does not make a copy of dv; so don't pass this function
@@ -136,8 +92,8 @@ void datavals_delete(datavalhead *headp);
  * this function.  If dv was actually appended (it wasn't NULL), then
  * returns dv, otherwise returns NULL.
  */
-dataval *datavals_append(datavalhead *headp, dataval *dv);
+dataval *dvs_append(datavalhead *headp, dataval *dv);
 
-void datavals_print(const datavalhead *head);
+void dvs_print(const datavalhead *head);
 
 #endif
diff --git a/libyasm/linemgr.c b/libyasm/linemgr.c
index c21436a7..2239872f 100644
--- a/libyasm/linemgr.c
+++ b/libyasm/linemgr.c
@@ -29,7 +29,6 @@ RCSID("$IdPath$");
 
 const char *in_filename = (const char *)NULL;
 unsigned int line_number = 1;
-unsigned char mode_bits = 0;
 unsigned int asm_options = 0;
 
 static ternary_tree filename_table = (ternary_tree)NULL;
diff --git a/libyasm/linemgr.h b/libyasm/linemgr.h
index 23376e13..d0457793 100644
--- a/libyasm/linemgr.h
+++ b/libyasm/linemgr.h
@@ -24,7 +24,6 @@
 
 extern const char *in_filename;
 extern unsigned int line_number;
-extern unsigned char mode_bits;
 extern unsigned int asm_options;
 
 void switch_filename(const char *filename);
diff --git a/libyasm/section.c b/libyasm/section.c
index 0ebccb7e..a95d185a 100644
--- a/libyasm/section.c
+++ b/libyasm/section.c
@@ -134,7 +134,7 @@ sections_parser_finalize(sectionhead *headp)
     section *cur;
     
     STAILQ_FOREACH(cur, headp, link)
-	bytecodes_parser_finalize(&cur->bc);
+	bcs_parser_finalize(&cur->bc);
 }
 
 bytecodehead *
@@ -156,7 +156,7 @@ section_delete(section *sect)
 	return;
 
     xfree(sect->name);
-    bytecodes_delete(&sect->bc);
+    bcs_delete(&sect->bc);
     xfree(sect);
 }
 
@@ -176,5 +176,5 @@ section_print(const section *sect)
     }
 
     printf(" Bytecodes:\n");
-    bytecodes_print(&sect->bc);
+    bcs_print(&sect->bc);
 }
diff --git a/libyasm/symrec.c b/libyasm/symrec.c
index eccb034f..020dee11 100644
--- a/libyasm/symrec.c
+++ b/libyasm/symrec.c
@@ -290,7 +290,7 @@ symrec_print(const symrec *sym)
 		printf("[First bytecode]\n");
 	    else {
 		printf("[Preceding bytecode]\n");
-		bytecode_print(sym->value.label.bc);
+		bc_print(sym->value.label.bc);
 	    }
 	    break;
     }
diff --git a/libyasm/tests/Makefile.am b/libyasm/tests/Makefile.am
index 9c7d9920..36e4bb1d 100644
--- a/libyasm/tests/Makefile.am
+++ b/libyasm/tests/Makefile.am
@@ -26,6 +26,7 @@ LDADD = \
 	$(top_builddir)/src/preprocs/raw/libpreproc.a		\
 	$(top_builddir)/src/optimizers/dbg/liboptimizer.a	\
 	$(top_builddir)/src/objfmts/dbg/libobjfmt.a		\
+	$(top_builddir)/src/arch/@ARCH@/libarch.a		\
 	$(top_builddir)/src/libyasm.a				\
 	$(INTLLIBS)
 
@@ -54,5 +55,5 @@ memexpr_test_SOURCES = \
 	memexpr_test.c
 
 INCLUDES= -I$(top_srcdir) -I$(top_srcdir)/src -I$(top_srcdir)/check \
-	-I$(top_builddir)/intl
+	-I$(top_srcdir)/src/arch/@ARCH@ -I$(top_builddir)/intl
 
diff --git a/libyasm/tests/bytecode_test.c b/libyasm/tests/bytecode_test.c
index 77eadc6a..f3411512 100644
--- a/libyasm/tests/bytecode_test.c
+++ b/libyasm/tests/bytecode_test.c
@@ -18,41 +18,41 @@
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
-#ifdef HAVE_CONFIG_H
-# include "config.h"
-#endif
-
-#ifdef STDC_HEADERS
-# include <stdlib.h>
-#endif
+#include "util.h"
 
 #include "check.h"
 
-#include "bytecode.c"
+#include "bytecode.h"
+#include "bc-int.h"
+#include "arch.h"
+#include "x86-int.h"
 
-START_TEST(test_effaddr_new_reg)
+START_TEST(test_x86_ea_new_reg)
 {
     effaddr *ea;
+    x86_effaddr_data *ead;
     int i;
 
     /* Test with NULL */
-    ea = effaddr_new_reg(1);
+    ea = x86_ea_new_reg(1);
     fail_unless(ea != NULL, "Should die if out of memory (not return NULL)");
 
     /* Test structure values function should set */
     fail_unless(ea->len == 0, "len should be 0");
-    fail_unless(ea->segment == 0, "Should be no segment override");
-    fail_unless(ea->valid_modrm == 1, "Mod/RM should be valid");
-    fail_unless(ea->need_modrm == 1, "Mod/RM should be needed");
-    fail_unless(ea->valid_sib == 0, "SIB should be invalid");
-    fail_unless(ea->need_sib == 0, "SIB should not be needed");
+    ead = ea_get_data(ea);
+    fail_unless(ead->segment == 0, "Should be no segment override");
+    fail_unless(ead->valid_modrm == 1, "Mod/RM should be valid");
+    fail_unless(ead->need_modrm == 1, "Mod/RM should be needed");
+    fail_unless(ead->valid_sib == 0, "SIB should be invalid");
+    fail_unless(ead->need_sib == 0, "SIB should not be needed");
 
     free(ea);
 
     /* Exhaustively test generated Mod/RM byte with register values */
     for(i=0; i<8; i++) {
-	ea = effaddr_new_reg(i);
-	fail_unless(ea->modrm == (0xC0 | (i & 0x07)),
+	ea = x86_ea_new_reg(i);
+	ead = ea_get_data(ea);
+	fail_unless(ead->modrm == (0xC0 | (i & 0x07)),
 		    "Invalid Mod/RM byte generated");
 	free(ea);
     }
@@ -66,7 +66,7 @@ bytecode_suite(void)
     TCase *tc_conversion = tcase_create("Conversion");
 
     suite_add_tcase(s, tc_conversion);
-    tcase_add_test(tc_conversion, test_effaddr_new_reg);
+    tcase_add_test(tc_conversion, test_x86_ea_new_reg);
 
     return s;
 }
diff --git a/modules/arch/x86/Makefile.am b/modules/arch/x86/Makefile.am
index 5847318c..5c5598d0 100644
--- a/modules/arch/x86/Makefile.am
+++ b/modules/arch/x86/Makefile.am
@@ -3,7 +3,10 @@
 noinst_LIBRARIES = libarch.a
 
 libarch_a_SOURCES = \
-	arch.c
+	x86arch.h	\
+	x86-int.h	\
+	arch.c		\
+	bytecode.c
 
 INCLUDES = \
 	-I$(top_srcdir)/src	\
diff --git a/modules/arch/x86/arch.c b/modules/arch/x86/arch.c
index a5df22fb..c9cf1cae 100644
--- a/modules/arch/x86/arch.c
+++ b/modules/arch/x86/arch.c
@@ -22,11 +22,22 @@
 #include "util.h"
 RCSID("$IdPath$");
 
+#include "bytecode.h"
 #include "arch.h"
 
+#include "x86-int.h"
+
+
+unsigned char x86_mode_bits = 0;
 
 /* Define arch structure -- see arch.h for details */
 arch x86_arch = {
     "x86 (IA-32, x86-64)",
-    "x86"
+    "x86",
+    {
+	X86_BYTECODE_TYPE_MAX,
+	x86_bc_delete,
+	x86_bc_print,
+	x86_bc_parser_finalize
+    }
 };
diff --git a/modules/arch/x86/bytecode.c b/modules/arch/x86/bytecode.c
new file mode 100644
index 00000000..80837116
--- /dev/null
+++ b/modules/arch/x86/bytecode.c
@@ -0,0 +1,512 @@
+/*
+ * x86 architecture description
+ *
+ *  Copyright (C) 2001  Peter Johnson
+ *
+ *  This file is part of YASM.
+ *
+ *  YASM is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  YASM is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+#include "util.h"
+RCSID("$IdPath$");
+
+#include "errwarn.h"
+#include "intnum.h"
+#include "expr.h"
+
+#include "bytecode.h"
+#include "arch.h"
+
+#include "x86-int.h"
+
+#include "bc-int.h"
+
+
+bytecode *
+x86_bc_new_insn(x86_new_insn_data *d)
+{
+    bytecode *bc;
+    x86_insn *insn;
+   
+    bc = bc_new_common(X86_BC_INSN, sizeof(x86_insn));
+    insn = bc_get_data(bc);
+
+    insn->ea = d->ea;
+    if (d->ea) {
+	x86_effaddr_data *ead = ea_get_data(d->ea);
+	ead->modrm &= 0xC7;	/* zero spare/reg bits */
+	ead->modrm |= (d->spare << 3) & 0x38;	/* plug in provided bits */
+    }
+
+    insn->imm = d->imm;
+    if (d->imm) {
+	insn->imm->f_len = d->im_len;
+	insn->imm->f_sign = d->im_sign;
+    }
+
+    insn->opcode[0] = d->op[0];
+    insn->opcode[1] = d->op[1];
+    insn->opcode[2] = d->op[2];
+    insn->opcode_len = d->op_len;
+
+    insn->addrsize = 0;
+    insn->opersize = d->opersize;
+    insn->lockrep_pre = 0;
+    insn->shift_op = 0;
+
+    insn->mode_bits = x86_mode_bits;
+
+    return bc;
+}
+
+bytecode *
+x86_bc_new_jmprel(x86_new_jmprel_data *d)
+{
+    bytecode *bc;
+    x86_jmprel *jmprel;
+
+    bc = bc_new_common(X86_BC_JMPREL, sizeof(x86_jmprel));
+    jmprel = bc_get_data(bc);
+
+    jmprel->target = d->target->val;
+    jmprel->op_sel = d->target->op_sel;
+
+    if ((d->target->op_sel == JR_SHORT_FORCED) && (d->near_op_len == 0))
+	Error(_("no SHORT form of that jump instruction exists"));
+    if ((d->target->op_sel == JR_NEAR_FORCED) && (d->short_op_len == 0))
+	Error(_("no NEAR form of that jump instruction exists"));
+
+    jmprel->shortop.opcode[0] = d->short_op[0];
+    jmprel->shortop.opcode[1] = d->short_op[1];
+    jmprel->shortop.opcode[2] = d->short_op[2];
+    jmprel->shortop.opcode_len = d->short_op_len;
+
+    jmprel->nearop.opcode[0] = d->near_op[0];
+    jmprel->nearop.opcode[1] = d->near_op[1];
+    jmprel->nearop.opcode[2] = d->near_op[2];
+    jmprel->nearop.opcode_len = d->near_op_len;
+
+    jmprel->addrsize = d->addrsize;
+    jmprel->opersize = 0;
+    jmprel->lockrep_pre = 0;
+
+    jmprel->mode_bits = x86_mode_bits;
+
+    return bc;
+}
+
+void
+x86_ea_set_segment(effaddr *ea, unsigned char segment)
+{
+    x86_effaddr_data *ead;
+
+    if (!ea)
+	return;
+
+    ead = ea_get_data(ea);
+
+    if (segment != 0 && ead->segment != 0)
+	Warning(_("multiple segment overrides, using leftmost"));
+
+    ead->segment = segment;
+}
+
+effaddr *
+x86_ea_new_reg(unsigned long reg)
+{
+    effaddr *ea = xmalloc(sizeof(effaddr)+sizeof(x86_effaddr_data));
+    x86_effaddr_data *ead = ea_get_data(ea);
+
+    ea->disp = (expr *)NULL;
+    ea->len = 0;
+    ea->nosplit = 0;
+    ead->segment = 0;
+    ead->modrm = 0xC0 | (reg & 0x07);	/* Mod=11, R/M=Reg, Reg=0 */
+    ead->valid_modrm = 1;
+    ead->need_modrm = 1;
+    ead->valid_sib = 0;
+    ead->need_sib = 0;
+
+    return ea;
+}
+
+effaddr *
+x86_ea_new_expr(expr *e)
+{
+    effaddr *ea = xmalloc(sizeof(effaddr)+sizeof(x86_effaddr_data));
+    x86_effaddr_data *ead = ea_get_data(ea);
+
+    ea->disp = e;
+    ea->len = 0;
+    ea->nosplit = 0;
+    ead->segment = 0;
+    ead->modrm = 0;
+    ead->valid_modrm = 0;
+    ead->need_modrm = 1;
+    ead->valid_sib = 0;
+    ead->need_sib = 0xff;   /* we won't know until we know more about expr and
+			       the BITS/address override setting */
+
+    return ea;
+}
+
+effaddr *
+x86_ea_new_imm(immval *imm, unsigned char im_len)
+{
+    effaddr *ea = xmalloc(sizeof(effaddr)+sizeof(x86_effaddr_data));
+    x86_effaddr_data *ead = ea_get_data(ea);
+
+    ea->disp = imm->val;
+    ea->len = im_len;
+    ea->nosplit = 0;
+    ead->segment = 0;
+    ead->modrm = 0;
+    ead->valid_modrm = 0;
+    ead->need_modrm = 0;
+    ead->valid_sib = 0;
+    ead->need_sib = 0;
+
+    return ea;
+}
+
+effaddr *
+x86_bc_insn_get_ea(bytecode *bc)
+{
+    x86_insn *insn = bc_get_data(bc);
+
+    if (!bc)
+	return NULL;
+
+    if (bc->type != X86_BC_INSN)
+	InternalError(_("Trying to get EA of non-instruction"));
+
+    return insn->ea;
+}
+
+void
+x86_bc_insn_opersize_override(bytecode *bc, unsigned char opersize)
+{
+    x86_insn *insn;
+    x86_jmprel *jmprel;
+
+    if (!bc)
+	return;
+
+    switch (bc->type) {
+	case X86_BC_INSN:
+	    insn = bc_get_data(bc);
+	    insn->opersize = opersize;
+	    break;
+	case X86_BC_JMPREL:
+	    jmprel = bc_get_data(bc);
+	    jmprel->opersize = opersize;
+	    break;
+	default:
+	    InternalError(_("OperSize override applied to non-instruction"));
+	    return;
+    }
+}
+
+void
+x86_bc_insn_addrsize_override(bytecode *bc, unsigned char addrsize)
+{
+    x86_insn *insn;
+    x86_jmprel *jmprel;
+
+    if (!bc)
+	return;
+
+    switch (bc->type) {
+	case X86_BC_INSN:
+	    insn = bc_get_data(bc);
+	    insn->addrsize = addrsize;
+	    break;
+	case X86_BC_JMPREL:
+	    jmprel = bc_get_data(bc);
+	    jmprel->addrsize = addrsize;
+	    break;
+	default:
+	    InternalError(_("AddrSize override applied to non-instruction"));
+	    return;
+    }
+}
+
+void
+x86_bc_insn_set_lockrep_prefix(bytecode *bc, unsigned char prefix)
+{
+    x86_insn *insn;
+    x86_jmprel *jmprel;
+    unsigned char *lockrep_pre = (unsigned char *)NULL;
+
+    if (!bc)
+	return;
+
+    switch (bc->type) {
+	case X86_BC_INSN:
+	    insn = bc_get_data(bc);
+	    lockrep_pre = &insn->lockrep_pre;
+	    break;
+	case X86_BC_JMPREL:
+	    jmprel = bc_get_data(bc);
+	    lockrep_pre = &jmprel->lockrep_pre;
+	    break;
+	default:
+	    InternalError(_("LockRep prefix applied to non-instruction"));
+	    return;
+    }
+
+    if (*lockrep_pre != 0)
+	Warning(_("multiple LOCK or REP prefixes, using leftmost"));
+
+    *lockrep_pre = prefix;
+}
+
+void
+x86_bc_insn_set_shift_flag(bytecode *bc)
+{
+    x86_insn *insn;
+
+    if (!bc)
+	return;
+
+    if (bc->type != X86_BC_INSN)
+	InternalError(_("Attempted to set shift flag on non-instruction"));
+
+    insn = bc_get_data(bc);
+
+    insn->shift_op = 1;
+}
+
+void
+x86_set_jmprel_opcode_sel(x86_jmprel_opcode_sel *old_sel,
+			  x86_jmprel_opcode_sel new_sel)
+{
+    if (!old_sel)
+	return;
+
+    if (new_sel != JR_NONE && ((*old_sel == JR_SHORT_FORCED) ||
+			       (*old_sel == JR_NEAR_FORCED)))
+	Warning(_("multiple SHORT or NEAR specifiers, using leftmost"));
+    *old_sel = new_sel;
+}
+
+void
+x86_bc_delete(bytecode *bc)
+{
+    x86_insn *insn;
+    x86_jmprel *jmprel;
+
+    switch ((x86_bytecode_type)bc->type) {
+	case X86_BC_INSN:
+	    insn = bc_get_data(bc);
+	    if (insn->ea) {
+		expr_delete(insn->ea->disp);
+		xfree(insn->ea);
+	    }
+	    if (insn->imm) {
+		expr_delete(insn->imm->val);
+		xfree(insn->imm);
+	    }
+	    break;
+	case X86_BC_JMPREL:
+	    jmprel = bc_get_data(bc);
+	    expr_delete(jmprel->target);
+	    break;
+    }
+}
+
+void
+x86_bc_print(const bytecode *bc)
+{
+    const x86_insn *insn;
+    const x86_jmprel *jmprel;
+    x86_effaddr_data *ead;
+
+    switch ((x86_bytecode_type)bc->type) {
+	case X86_BC_INSN:
+	    insn = bc_get_const_data(bc);
+	    printf("_Instruction_\n");
+	    printf("Effective Address:");
+	    if (!insn->ea)
+		printf(" (nil)\n");
+	    else {
+		printf("\n Disp=");
+		if (insn->ea->disp)
+		    expr_print(insn->ea->disp);
+		else
+		    printf("(nil)");
+		printf("\n");
+		ead = ea_get_data(insn->ea);
+		printf(" Len=%u SegmentOv=%02x NoSplit=%u\n",
+		       (unsigned int)insn->ea->len,
+		       (unsigned int)ead->segment,
+		       (unsigned int)insn->ea->nosplit);
+		printf(" ModRM=%03o ValidRM=%u NeedRM=%u\n",
+		       (unsigned int)ead->modrm,
+		       (unsigned int)ead->valid_modrm,
+		       (unsigned int)ead->need_modrm);
+		printf(" SIB=%03o ValidSIB=%u NeedSIB=%u\n",
+		       (unsigned int)ead->sib,
+		       (unsigned int)ead->valid_sib,
+		       (unsigned int)ead->need_sib);
+	    }
+	    printf("Immediate Value:");
+	    if (!insn->imm)
+		printf(" (nil)\n");
+	    else {
+		printf("\n Val=");
+		expr_print(insn->imm->val);
+		printf("\n");
+		printf(" Len=%u, IsNeg=%u\n",
+		       (unsigned int)insn->imm->len,
+		       (unsigned int)insn->imm->isneg);
+		printf(" FLen=%u, FSign=%u\n",
+		       (unsigned int)insn->imm->f_len,
+		       (unsigned int)insn->imm->f_sign);
+	    }
+	    printf("Opcode: %02x %02x %02x OpLen=%u\n",
+		   (unsigned int)insn->opcode[0],
+		   (unsigned int)insn->opcode[1],
+		   (unsigned int)insn->opcode[2],
+		   (unsigned int)insn->opcode_len);
+	    printf("AddrSize=%u OperSize=%u LockRepPre=%02x ShiftOp=%u\n",
+		   (unsigned int)insn->addrsize,
+		   (unsigned int)insn->opersize,
+		   (unsigned int)insn->lockrep_pre,
+		   (unsigned int)insn->shift_op);
+	    printf("BITS=%u\n", (unsigned int)insn->mode_bits);
+	    break;
+	case X86_BC_JMPREL:
+	    jmprel = bc_get_const_data(bc);
+	    printf("_Relative Jump_\n");
+	    printf("Target=");
+	    expr_print(jmprel->target);
+	    printf("\nShort Form:\n");
+	    if (!jmprel->shortop.opcode_len == 0)
+		printf(" None\n");
+	    else
+		printf(" Opcode: %02x %02x %02x OpLen=%u\n",
+		       (unsigned int)jmprel->shortop.opcode[0],
+		       (unsigned int)jmprel->shortop.opcode[1],
+		       (unsigned int)jmprel->shortop.opcode[2],
+		       (unsigned int)jmprel->shortop.opcode_len);
+	    if (!jmprel->nearop.opcode_len == 0)
+		printf(" None\n");
+	    else
+		printf(" Opcode: %02x %02x %02x OpLen=%u\n",
+		       (unsigned int)jmprel->nearop.opcode[0],
+		       (unsigned int)jmprel->nearop.opcode[1],
+		       (unsigned int)jmprel->nearop.opcode[2],
+		       (unsigned int)jmprel->nearop.opcode_len);
+	    printf("OpSel=");
+	    switch (jmprel->op_sel) {
+		case JR_NONE:
+		    printf("None");
+		    break;
+		case JR_SHORT:
+		    printf("Short");
+		    break;
+		case JR_NEAR:
+		    printf("Near");
+		    break;
+		case JR_SHORT_FORCED:
+		    printf("Forced Short");
+		    break;
+		case JR_NEAR_FORCED:
+		    printf("Forced Near");
+		    break;
+		default:
+		    printf("UNKNOWN!!");
+		    break;
+	    }
+	    printf("BITS=%u\nAddrSize=%u OperSize=%u LockRepPre=%02x\n",
+		   (unsigned int)jmprel->mode_bits,
+		   (unsigned int)jmprel->addrsize,
+		   (unsigned int)jmprel->opersize,
+		   (unsigned int)jmprel->lockrep_pre);
+	    break;
+    }
+}
+
+static void
+x86_bc_parser_finalize_insn(x86_insn *insn)
+{
+    effaddr *ea = insn->ea;
+    x86_effaddr_data *ead = ea_get_data(ea);
+    immval *imm = insn->imm;
+
+    if (ea) {
+	if ((ea->disp) && ((!ead->valid_sib && ead->need_sib) ||
+			   (!ead->valid_modrm && ead->need_modrm))) {
+	    /* First expand equ's */
+	    expr_expand_equ(ea->disp);
+
+	    /* Check validity of effective address and calc R/M bits of
+	     * Mod/RM byte and SIB byte.  We won't know the Mod field
+	     * of the Mod/RM byte until we know more about the
+	     * displacement.
+	     */
+	    if (!expr_checkea(&ea->disp, &insn->addrsize, insn->mode_bits,
+			      ea->nosplit, &ea->len, &ead->modrm,
+			      &ead->valid_modrm, &ead->need_modrm, &ead->sib,
+			      &ead->valid_sib, &ead->need_sib))
+		return;	    /* failed, don't bother checking rest of insn */
+	}
+    }
+
+    if (imm) {
+	const intnum *num;
+
+	if (imm->val) {
+	    expr_expand_equ(imm->val);
+	    expr_simplify(imm->val);
+	}
+	/* TODO: check imm f_len vs. len? */
+
+	/* Handle shift_op special-casing */
+	if (insn->shift_op && (num = expr_get_intnum(&imm->val))) {
+	    if (intnum_get_uint(num) == 1) {
+		/* Use ,1 form: first copy ,1 opcode. */
+		insn->opcode[0] = insn->opcode[1];
+		/* Delete ModRM, as it's no longer needed */
+		xfree(ea);
+		insn->ea = (effaddr *)NULL;
+		/* Delete Imm, as it's not needed */
+		expr_delete(imm->val);
+		xfree(imm);
+		insn->imm = (immval *)NULL;
+	    }
+	    insn->shift_op = 0;
+	}
+    }
+
+    
+}
+
+void
+x86_bc_parser_finalize(bytecode *bc)
+{
+    x86_insn *insn;
+
+    switch ((x86_bytecode_type)bc->type) {
+	case X86_BC_INSN:
+	    insn = bc_get_data(bc);
+	    x86_bc_parser_finalize_insn(insn);
+	    break;
+	default:
+	    break;
+    }
+}
+
diff --git a/modules/arch/x86/x86-int.h b/modules/arch/x86/x86-int.h
new file mode 100644
index 00000000..2c3336ee
--- /dev/null
+++ b/modules/arch/x86/x86-int.h
@@ -0,0 +1,95 @@
+/* $IdPath$
+ * x86 internals header file
+ *
+ *  Copyright (C) 2001  Peter Johnson
+ *
+ *  This file is part of YASM.
+ *
+ *  YASM is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  YASM is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+#ifndef YASM_X86_INT_H
+#define YASM_X86_INT_H
+
+typedef struct x86_effaddr_data {
+    unsigned char segment;	/* segment override, 0 if none */
+
+    /* How the spare (register) bits in Mod/RM are handled:
+     * Even if valid_modrm=0, the spare bits are still valid (don't overwrite!)
+     * They're set in bytecode_new_insn().
+     */
+    unsigned char modrm;
+    unsigned char valid_modrm;	/* 1 if Mod/RM byte currently valid, 0 if not */
+    unsigned char need_modrm;	/* 1 if Mod/RM byte needed, 0 if not */
+
+    unsigned char sib;
+    unsigned char valid_sib;	/* 1 if SIB byte currently valid, 0 if not */
+    unsigned char need_sib;	/* 1 if SIB byte needed, 0 if not,
+				   0xff if unknown */
+} x86_effaddr_data;
+
+typedef struct x86_insn {
+    effaddr *ea;	/* effective address */
+
+    immval *imm;	/* immediate or relative value */
+
+    unsigned char opcode[3];	/* opcode */
+    unsigned char opcode_len;
+
+    unsigned char addrsize;	/* 0 or =mode_bits => no override */
+    unsigned char opersize;	/* 0 indicates no override */
+    unsigned char lockrep_pre;	/* 0 indicates no prefix */
+
+    /* HACK, but a space-saving one: shift opcodes have an immediate
+     * form and a ,1 form (with no immediate).  In the parser, we
+     * set this and opcode_len=1, but store the ,1 version in the
+     * second byte of the opcode array.  We then choose between the
+     * two versions once we know the actual value of imm (because we
+     * don't know it in the parser module).
+     *
+     * A override to force the imm version should just leave this at
+     * 0.  Then later code won't know the ,1 version even exists.
+     * TODO: Figure out how this affects CPU flags processing.
+     *
+     * Call x86_SetInsnShiftFlag() to set this flag to 1.
+     */
+    unsigned char shift_op;
+
+    unsigned char mode_bits;
+} x86_insn;
+
+typedef struct x86_jmprel {
+    expr *target;		/* target location */
+
+    struct {
+	unsigned char opcode[3];
+	unsigned char opcode_len;   /* 0 = no opc for this version */
+    } shortop, nearop;
+
+    /* which opcode are we using? */
+    /* The *FORCED forms are specified in the source as such */
+    x86_jmprel_opcode_sel op_sel;
+
+    unsigned char addrsize;	/* 0 or =mode_bits => no override */
+    unsigned char opersize;	/* 0 indicates no override */
+    unsigned char lockrep_pre;	/* 0 indicates no prefix */
+
+    unsigned char mode_bits;
+} x86_jmprel;
+
+void x86_bc_delete(bytecode *bc);
+void x86_bc_print(const bytecode *bc);
+void x86_bc_parser_finalize(bytecode *bc);
+
+#endif
diff --git a/modules/arch/x86/x86arch.c b/modules/arch/x86/x86arch.c
index a5df22fb..c9cf1cae 100644
--- a/modules/arch/x86/x86arch.c
+++ b/modules/arch/x86/x86arch.c
@@ -22,11 +22,22 @@
 #include "util.h"
 RCSID("$IdPath$");
 
+#include "bytecode.h"
 #include "arch.h"
 
+#include "x86-int.h"
+
+
+unsigned char x86_mode_bits = 0;
 
 /* Define arch structure -- see arch.h for details */
 arch x86_arch = {
     "x86 (IA-32, x86-64)",
-    "x86"
+    "x86",
+    {
+	X86_BYTECODE_TYPE_MAX,
+	x86_bc_delete,
+	x86_bc_print,
+	x86_bc_parser_finalize
+    }
 };
diff --git a/modules/arch/x86/x86arch.h b/modules/arch/x86/x86arch.h
new file mode 100644
index 00000000..70a207c1
--- /dev/null
+++ b/modules/arch/x86/x86arch.h
@@ -0,0 +1,93 @@
+/* $IdPath$
+ * x86 Architecture header file
+ *
+ *  Copyright (C) 2001  Peter Johnson
+ *
+ *  This file is part of YASM.
+ *
+ *  YASM is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  YASM is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+#ifndef YASM_X86ARCH_H
+#define YASM_X86ARCH_H
+
+typedef enum {
+    X86_BC_INSN = BYTECODE_TYPE_BASE,
+    X86_BC_JMPREL
+} x86_bytecode_type;
+#define X86_BYTECODE_TYPE_MAX	X86_BC_JMPREL+1
+
+typedef enum {
+    JR_NONE,
+    JR_SHORT,
+    JR_NEAR,
+    JR_SHORT_FORCED,
+    JR_NEAR_FORCED
+} x86_jmprel_opcode_sel;
+
+typedef struct x86_targetval {
+    expr *val;
+
+    x86_jmprel_opcode_sel op_sel;
+} x86_targetval;
+
+void x86_ea_set_segment(effaddr *ea, unsigned char segment);
+effaddr *x86_ea_new_reg(unsigned long reg);
+effaddr *x86_ea_new_imm(immval *imm, unsigned char im_len);
+effaddr *x86_ea_new_expr(expr *e);
+
+effaddr *x86_bc_insn_get_ea(bytecode *bc);
+
+void x86_bc_insn_opersize_override(bytecode *bc, unsigned char opersize);
+void x86_bc_insn_addrsize_override(bytecode *bc, unsigned char addrsize);
+void x86_bc_insn_set_lockrep_prefix(bytecode *bc, unsigned char prefix);
+void x86_bc_insn_set_shift_flag(bytecode *bc);
+
+void x86_set_jmprel_opcode_sel(x86_jmprel_opcode_sel *old_sel,
+			       x86_jmprel_opcode_sel new_sel);
+
+/* Structure with *all* inputs passed to x86_bytecode_new_insn().
+ * IMPORTANT: ea_ptr and im_ptr cannot be reused or freed after calling the
+ * function (it doesn't make a copy).
+ */
+typedef struct x86_new_insn_data {
+    effaddr *ea;
+    immval *imm;
+    unsigned char opersize;
+    unsigned char op_len;
+    unsigned char op[3];
+    unsigned char spare;	/* bits to go in 'spare' field of ModRM */
+    unsigned char im_len;
+    unsigned char im_sign;
+} x86_new_insn_data;
+
+bytecode *x86_bc_new_insn(x86_new_insn_data *d);
+
+/* Structure with *all* inputs passed to x86_bytecode_new_jmprel().
+ * Pass 0 for the opcode_len if that version of the opcode doesn't exist.
+ */
+typedef struct x86_new_jmprel_data {
+    x86_targetval *target;
+    unsigned char short_op_len;
+    unsigned char short_op[3];
+    unsigned char near_op_len;
+    unsigned char near_op[3];
+    unsigned char addrsize;
+} x86_new_jmprel_data;
+
+bytecode *x86_bc_new_jmprel(x86_new_jmprel_data *d);
+
+extern unsigned char x86_mode_bits;
+
+#endif
diff --git a/modules/arch/x86/x86bc.c b/modules/arch/x86/x86bc.c
new file mode 100644
index 00000000..80837116
--- /dev/null
+++ b/modules/arch/x86/x86bc.c
@@ -0,0 +1,512 @@
+/*
+ * x86 architecture description
+ *
+ *  Copyright (C) 2001  Peter Johnson
+ *
+ *  This file is part of YASM.
+ *
+ *  YASM is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  YASM is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+#include "util.h"
+RCSID("$IdPath$");
+
+#include "errwarn.h"
+#include "intnum.h"
+#include "expr.h"
+
+#include "bytecode.h"
+#include "arch.h"
+
+#include "x86-int.h"
+
+#include "bc-int.h"
+
+
+bytecode *
+x86_bc_new_insn(x86_new_insn_data *d)
+{
+    bytecode *bc;
+    x86_insn *insn;
+   
+    bc = bc_new_common(X86_BC_INSN, sizeof(x86_insn));
+    insn = bc_get_data(bc);
+
+    insn->ea = d->ea;
+    if (d->ea) {
+	x86_effaddr_data *ead = ea_get_data(d->ea);
+	ead->modrm &= 0xC7;	/* zero spare/reg bits */
+	ead->modrm |= (d->spare << 3) & 0x38;	/* plug in provided bits */
+    }
+
+    insn->imm = d->imm;
+    if (d->imm) {
+	insn->imm->f_len = d->im_len;
+	insn->imm->f_sign = d->im_sign;
+    }
+
+    insn->opcode[0] = d->op[0];
+    insn->opcode[1] = d->op[1];
+    insn->opcode[2] = d->op[2];
+    insn->opcode_len = d->op_len;
+
+    insn->addrsize = 0;
+    insn->opersize = d->opersize;
+    insn->lockrep_pre = 0;
+    insn->shift_op = 0;
+
+    insn->mode_bits = x86_mode_bits;
+
+    return bc;
+}
+
+bytecode *
+x86_bc_new_jmprel(x86_new_jmprel_data *d)
+{
+    bytecode *bc;
+    x86_jmprel *jmprel;
+
+    bc = bc_new_common(X86_BC_JMPREL, sizeof(x86_jmprel));
+    jmprel = bc_get_data(bc);
+
+    jmprel->target = d->target->val;
+    jmprel->op_sel = d->target->op_sel;
+
+    if ((d->target->op_sel == JR_SHORT_FORCED) && (d->near_op_len == 0))
+	Error(_("no SHORT form of that jump instruction exists"));
+    if ((d->target->op_sel == JR_NEAR_FORCED) && (d->short_op_len == 0))
+	Error(_("no NEAR form of that jump instruction exists"));
+
+    jmprel->shortop.opcode[0] = d->short_op[0];
+    jmprel->shortop.opcode[1] = d->short_op[1];
+    jmprel->shortop.opcode[2] = d->short_op[2];
+    jmprel->shortop.opcode_len = d->short_op_len;
+
+    jmprel->nearop.opcode[0] = d->near_op[0];
+    jmprel->nearop.opcode[1] = d->near_op[1];
+    jmprel->nearop.opcode[2] = d->near_op[2];
+    jmprel->nearop.opcode_len = d->near_op_len;
+
+    jmprel->addrsize = d->addrsize;
+    jmprel->opersize = 0;
+    jmprel->lockrep_pre = 0;
+
+    jmprel->mode_bits = x86_mode_bits;
+
+    return bc;
+}
+
+void
+x86_ea_set_segment(effaddr *ea, unsigned char segment)
+{
+    x86_effaddr_data *ead;
+
+    if (!ea)
+	return;
+
+    ead = ea_get_data(ea);
+
+    if (segment != 0 && ead->segment != 0)
+	Warning(_("multiple segment overrides, using leftmost"));
+
+    ead->segment = segment;
+}
+
+effaddr *
+x86_ea_new_reg(unsigned long reg)
+{
+    effaddr *ea = xmalloc(sizeof(effaddr)+sizeof(x86_effaddr_data));
+    x86_effaddr_data *ead = ea_get_data(ea);
+
+    ea->disp = (expr *)NULL;
+    ea->len = 0;
+    ea->nosplit = 0;
+    ead->segment = 0;
+    ead->modrm = 0xC0 | (reg & 0x07);	/* Mod=11, R/M=Reg, Reg=0 */
+    ead->valid_modrm = 1;
+    ead->need_modrm = 1;
+    ead->valid_sib = 0;
+    ead->need_sib = 0;
+
+    return ea;
+}
+
+effaddr *
+x86_ea_new_expr(expr *e)
+{
+    effaddr *ea = xmalloc(sizeof(effaddr)+sizeof(x86_effaddr_data));
+    x86_effaddr_data *ead = ea_get_data(ea);
+
+    ea->disp = e;
+    ea->len = 0;
+    ea->nosplit = 0;
+    ead->segment = 0;
+    ead->modrm = 0;
+    ead->valid_modrm = 0;
+    ead->need_modrm = 1;
+    ead->valid_sib = 0;
+    ead->need_sib = 0xff;   /* we won't know until we know more about expr and
+			       the BITS/address override setting */
+
+    return ea;
+}
+
+effaddr *
+x86_ea_new_imm(immval *imm, unsigned char im_len)
+{
+    effaddr *ea = xmalloc(sizeof(effaddr)+sizeof(x86_effaddr_data));
+    x86_effaddr_data *ead = ea_get_data(ea);
+
+    ea->disp = imm->val;
+    ea->len = im_len;
+    ea->nosplit = 0;
+    ead->segment = 0;
+    ead->modrm = 0;
+    ead->valid_modrm = 0;
+    ead->need_modrm = 0;
+    ead->valid_sib = 0;
+    ead->need_sib = 0;
+
+    return ea;
+}
+
+effaddr *
+x86_bc_insn_get_ea(bytecode *bc)
+{
+    x86_insn *insn = bc_get_data(bc);
+
+    if (!bc)
+	return NULL;
+
+    if (bc->type != X86_BC_INSN)
+	InternalError(_("Trying to get EA of non-instruction"));
+
+    return insn->ea;
+}
+
+void
+x86_bc_insn_opersize_override(bytecode *bc, unsigned char opersize)
+{
+    x86_insn *insn;
+    x86_jmprel *jmprel;
+
+    if (!bc)
+	return;
+
+    switch (bc->type) {
+	case X86_BC_INSN:
+	    insn = bc_get_data(bc);
+	    insn->opersize = opersize;
+	    break;
+	case X86_BC_JMPREL:
+	    jmprel = bc_get_data(bc);
+	    jmprel->opersize = opersize;
+	    break;
+	default:
+	    InternalError(_("OperSize override applied to non-instruction"));
+	    return;
+    }
+}
+
+void
+x86_bc_insn_addrsize_override(bytecode *bc, unsigned char addrsize)
+{
+    x86_insn *insn;
+    x86_jmprel *jmprel;
+
+    if (!bc)
+	return;
+
+    switch (bc->type) {
+	case X86_BC_INSN:
+	    insn = bc_get_data(bc);
+	    insn->addrsize = addrsize;
+	    break;
+	case X86_BC_JMPREL:
+	    jmprel = bc_get_data(bc);
+	    jmprel->addrsize = addrsize;
+	    break;
+	default:
+	    InternalError(_("AddrSize override applied to non-instruction"));
+	    return;
+    }
+}
+
+void
+x86_bc_insn_set_lockrep_prefix(bytecode *bc, unsigned char prefix)
+{
+    x86_insn *insn;
+    x86_jmprel *jmprel;
+    unsigned char *lockrep_pre = (unsigned char *)NULL;
+
+    if (!bc)
+	return;
+
+    switch (bc->type) {
+	case X86_BC_INSN:
+	    insn = bc_get_data(bc);
+	    lockrep_pre = &insn->lockrep_pre;
+	    break;
+	case X86_BC_JMPREL:
+	    jmprel = bc_get_data(bc);
+	    lockrep_pre = &jmprel->lockrep_pre;
+	    break;
+	default:
+	    InternalError(_("LockRep prefix applied to non-instruction"));
+	    return;
+    }
+
+    if (*lockrep_pre != 0)
+	Warning(_("multiple LOCK or REP prefixes, using leftmost"));
+
+    *lockrep_pre = prefix;
+}
+
+void
+x86_bc_insn_set_shift_flag(bytecode *bc)
+{
+    x86_insn *insn;
+
+    if (!bc)
+	return;
+
+    if (bc->type != X86_BC_INSN)
+	InternalError(_("Attempted to set shift flag on non-instruction"));
+
+    insn = bc_get_data(bc);
+
+    insn->shift_op = 1;
+}
+
+void
+x86_set_jmprel_opcode_sel(x86_jmprel_opcode_sel *old_sel,
+			  x86_jmprel_opcode_sel new_sel)
+{
+    if (!old_sel)
+	return;
+
+    if (new_sel != JR_NONE && ((*old_sel == JR_SHORT_FORCED) ||
+			       (*old_sel == JR_NEAR_FORCED)))
+	Warning(_("multiple SHORT or NEAR specifiers, using leftmost"));
+    *old_sel = new_sel;
+}
+
+void
+x86_bc_delete(bytecode *bc)
+{
+    x86_insn *insn;
+    x86_jmprel *jmprel;
+
+    switch ((x86_bytecode_type)bc->type) {
+	case X86_BC_INSN:
+	    insn = bc_get_data(bc);
+	    if (insn->ea) {
+		expr_delete(insn->ea->disp);
+		xfree(insn->ea);
+	    }
+	    if (insn->imm) {
+		expr_delete(insn->imm->val);
+		xfree(insn->imm);
+	    }
+	    break;
+	case X86_BC_JMPREL:
+	    jmprel = bc_get_data(bc);
+	    expr_delete(jmprel->target);
+	    break;
+    }
+}
+
+void
+x86_bc_print(const bytecode *bc)
+{
+    const x86_insn *insn;
+    const x86_jmprel *jmprel;
+    x86_effaddr_data *ead;
+
+    switch ((x86_bytecode_type)bc->type) {
+	case X86_BC_INSN:
+	    insn = bc_get_const_data(bc);
+	    printf("_Instruction_\n");
+	    printf("Effective Address:");
+	    if (!insn->ea)
+		printf(" (nil)\n");
+	    else {
+		printf("\n Disp=");
+		if (insn->ea->disp)
+		    expr_print(insn->ea->disp);
+		else
+		    printf("(nil)");
+		printf("\n");
+		ead = ea_get_data(insn->ea);
+		printf(" Len=%u SegmentOv=%02x NoSplit=%u\n",
+		       (unsigned int)insn->ea->len,
+		       (unsigned int)ead->segment,
+		       (unsigned int)insn->ea->nosplit);
+		printf(" ModRM=%03o ValidRM=%u NeedRM=%u\n",
+		       (unsigned int)ead->modrm,
+		       (unsigned int)ead->valid_modrm,
+		       (unsigned int)ead->need_modrm);
+		printf(" SIB=%03o ValidSIB=%u NeedSIB=%u\n",
+		       (unsigned int)ead->sib,
+		       (unsigned int)ead->valid_sib,
+		       (unsigned int)ead->need_sib);
+	    }
+	    printf("Immediate Value:");
+	    if (!insn->imm)
+		printf(" (nil)\n");
+	    else {
+		printf("\n Val=");
+		expr_print(insn->imm->val);
+		printf("\n");
+		printf(" Len=%u, IsNeg=%u\n",
+		       (unsigned int)insn->imm->len,
+		       (unsigned int)insn->imm->isneg);
+		printf(" FLen=%u, FSign=%u\n",
+		       (unsigned int)insn->imm->f_len,
+		       (unsigned int)insn->imm->f_sign);
+	    }
+	    printf("Opcode: %02x %02x %02x OpLen=%u\n",
+		   (unsigned int)insn->opcode[0],
+		   (unsigned int)insn->opcode[1],
+		   (unsigned int)insn->opcode[2],
+		   (unsigned int)insn->opcode_len);
+	    printf("AddrSize=%u OperSize=%u LockRepPre=%02x ShiftOp=%u\n",
+		   (unsigned int)insn->addrsize,
+		   (unsigned int)insn->opersize,
+		   (unsigned int)insn->lockrep_pre,
+		   (unsigned int)insn->shift_op);
+	    printf("BITS=%u\n", (unsigned int)insn->mode_bits);
+	    break;
+	case X86_BC_JMPREL:
+	    jmprel = bc_get_const_data(bc);
+	    printf("_Relative Jump_\n");
+	    printf("Target=");
+	    expr_print(jmprel->target);
+	    printf("\nShort Form:\n");
+	    if (!jmprel->shortop.opcode_len == 0)
+		printf(" None\n");
+	    else
+		printf(" Opcode: %02x %02x %02x OpLen=%u\n",
+		       (unsigned int)jmprel->shortop.opcode[0],
+		       (unsigned int)jmprel->shortop.opcode[1],
+		       (unsigned int)jmprel->shortop.opcode[2],
+		       (unsigned int)jmprel->shortop.opcode_len);
+	    if (!jmprel->nearop.opcode_len == 0)
+		printf(" None\n");
+	    else
+		printf(" Opcode: %02x %02x %02x OpLen=%u\n",
+		       (unsigned int)jmprel->nearop.opcode[0],
+		       (unsigned int)jmprel->nearop.opcode[1],
+		       (unsigned int)jmprel->nearop.opcode[2],
+		       (unsigned int)jmprel->nearop.opcode_len);
+	    printf("OpSel=");
+	    switch (jmprel->op_sel) {
+		case JR_NONE:
+		    printf("None");
+		    break;
+		case JR_SHORT:
+		    printf("Short");
+		    break;
+		case JR_NEAR:
+		    printf("Near");
+		    break;
+		case JR_SHORT_FORCED:
+		    printf("Forced Short");
+		    break;
+		case JR_NEAR_FORCED:
+		    printf("Forced Near");
+		    break;
+		default:
+		    printf("UNKNOWN!!");
+		    break;
+	    }
+	    printf("BITS=%u\nAddrSize=%u OperSize=%u LockRepPre=%02x\n",
+		   (unsigned int)jmprel->mode_bits,
+		   (unsigned int)jmprel->addrsize,
+		   (unsigned int)jmprel->opersize,
+		   (unsigned int)jmprel->lockrep_pre);
+	    break;
+    }
+}
+
+static void
+x86_bc_parser_finalize_insn(x86_insn *insn)
+{
+    effaddr *ea = insn->ea;
+    x86_effaddr_data *ead = ea_get_data(ea);
+    immval *imm = insn->imm;
+
+    if (ea) {
+	if ((ea->disp) && ((!ead->valid_sib && ead->need_sib) ||
+			   (!ead->valid_modrm && ead->need_modrm))) {
+	    /* First expand equ's */
+	    expr_expand_equ(ea->disp);
+
+	    /* Check validity of effective address and calc R/M bits of
+	     * Mod/RM byte and SIB byte.  We won't know the Mod field
+	     * of the Mod/RM byte until we know more about the
+	     * displacement.
+	     */
+	    if (!expr_checkea(&ea->disp, &insn->addrsize, insn->mode_bits,
+			      ea->nosplit, &ea->len, &ead->modrm,
+			      &ead->valid_modrm, &ead->need_modrm, &ead->sib,
+			      &ead->valid_sib, &ead->need_sib))
+		return;	    /* failed, don't bother checking rest of insn */
+	}
+    }
+
+    if (imm) {
+	const intnum *num;
+
+	if (imm->val) {
+	    expr_expand_equ(imm->val);
+	    expr_simplify(imm->val);
+	}
+	/* TODO: check imm f_len vs. len? */
+
+	/* Handle shift_op special-casing */
+	if (insn->shift_op && (num = expr_get_intnum(&imm->val))) {
+	    if (intnum_get_uint(num) == 1) {
+		/* Use ,1 form: first copy ,1 opcode. */
+		insn->opcode[0] = insn->opcode[1];
+		/* Delete ModRM, as it's no longer needed */
+		xfree(ea);
+		insn->ea = (effaddr *)NULL;
+		/* Delete Imm, as it's not needed */
+		expr_delete(imm->val);
+		xfree(imm);
+		insn->imm = (immval *)NULL;
+	    }
+	    insn->shift_op = 0;
+	}
+    }
+
+    
+}
+
+void
+x86_bc_parser_finalize(bytecode *bc)
+{
+    x86_insn *insn;
+
+    switch ((x86_bytecode_type)bc->type) {
+	case X86_BC_INSN:
+	    insn = bc_get_data(bc);
+	    x86_bc_parser_finalize_insn(insn);
+	    break;
+	default:
+	    break;
+    }
+}
+
diff --git a/modules/parsers/nasm/bison.y.in b/modules/parsers/nasm/bison.y.in
index 54893a76..fa318fd3 100644
--- a/modules/parsers/nasm/bison.y.in
+++ b/modules/parsers/nasm/bison.y.in
@@ -40,6 +40,7 @@ RCSID("$IdPath$");
 #include "section.h"
 #include "objfmt.h"
 
+#include "arch.h"
 
 #define YYDEBUG 1
 
@@ -56,6 +57,9 @@ extern char *nasm_parser_locallabel_base;
 static bytecode *nasm_parser_prev_bc = (bytecode *)NULL;
 static bytecode *nasm_parser_temp_bc;
 
+/* additional data declarations (dynamically generated) */
+/* @DATADECLS@ */
+
 %}
 
 %union {
@@ -68,7 +72,7 @@ static bytecode *nasm_parser_temp_bc;
     effaddr *ea;
     expr *exp;
     immval *im_val;
-    targetval tgt_val;
+    x86_targetval tgt_val;
     datavalhead datahead;
     dataval *data;
     bytecode *bc;
@@ -126,7 +130,7 @@ static bytecode *nasm_parser_temp_bc;
 %%
 input: /* empty */
     | input line    {
-	nasm_parser_temp_bc = bytecodes_append(section_get_bytecodes(nasm_parser_cur_section),
+	nasm_parser_temp_bc = bcs_append(section_get_bytecodes(nasm_parser_cur_section),
 					       $2);
 	if (nasm_parser_temp_bc)
 	    nasm_parser_prev_bc = nasm_parser_temp_bc;
@@ -145,10 +149,10 @@ line: '\n'		{ $$ = (bytecode *)NULL; }
 ;
 
 lineexp: exp
-    | TIMES expr exp			{ $$ = $3; SetBCMultiple($$, $2); }
+    | TIMES expr exp			{ $$ = $3; bc_set_multiple($$, $2); }
     | label				{ $$ = (bytecode *)NULL; }
     | label exp				{ $$ = $2; }
-    | label TIMES expr exp		{ $$ = $4; SetBCMultiple($$, $3); }
+    | label TIMES expr exp		{ $$ = $4; bc_set_multiple($$, $3); }
     | label_id EQU expr			{
 	symrec_define_equ($1, $3);
 	xfree($1);
@@ -157,22 +161,16 @@ lineexp: exp
 ;
 
 exp: instr
-    | DECLARE_DATA datavals	    { $$ = bytecode_new_data(&$2, $1); }
-    | RESERVE_SPACE expr	    { $$ = bytecode_new_reserve($2, $1); }
+    | DECLARE_DATA datavals	    { $$ = bc_new_data(&$2, $1); }
+    | RESERVE_SPACE expr	    { $$ = bc_new_reserve($2, $1); }
 ;
 
-datavals: dataval	    {
-	datavals_initialize(&$$);
-	datavals_append(&$$, $1);
-    }
-    | datavals ',' dataval  {
-	datavals_append(&$1, $3);
-	$$ = $1;
-    }
+datavals: dataval	    { dvs_initialize(&$$); dvs_append(&$$, $1); }
+    | datavals ',' dataval  { dvs_append(&$1, $3); $$ = $1; }
 ;
 
-dataval: expr_no_string	{ $$ = dataval_new_expr($1); }
-    | STRING		{ $$ = dataval_new_string($1); }
+dataval: expr_no_string	{ $$ = dv_new_expr($1); }
+    | STRING		{ $$ = dv_new_string($1); }
     | error		{
 	Error(_("expression syntax error"));
 	$$ = (dataval *)NULL;
@@ -317,17 +315,20 @@ memexpr: INTNUM			{ $$ = expr_new_ident(ExprInt($1)); }
     | error			{ Error(_("invalid effective address")); }
 ;
 
-memaddr: memexpr	    { $$ = effaddr_new_expr($1); SetEASegment($$, 0); }
-    | REG_CS ':' memaddr    { $$ = $3; SetEASegment($$, 0x2E); }
-    | REG_SS ':' memaddr    { $$ = $3; SetEASegment($$, 0x36); }
-    | REG_DS ':' memaddr    { $$ = $3; SetEASegment($$, 0x3E); }
-    | REG_ES ':' memaddr    { $$ = $3; SetEASegment($$, 0x26); }
-    | REG_FS ':' memaddr    { $$ = $3; SetEASegment($$, 0x64); }
-    | REG_GS ':' memaddr    { $$ = $3; SetEASegment($$, 0x65); }
-    | BYTE memaddr	    { $$ = $2; SetEALen($$, 1); }
-    | WORD memaddr	    { $$ = $2; SetEALen($$, 2); }
-    | DWORD memaddr	    { $$ = $2; SetEALen($$, 4); }
-    | NOSPLIT memaddr	    { $$ = $2; SetEANosplit($$, 1); }
+memaddr: memexpr	    {
+	$$ = x86_ea_new_expr($1);
+	x86_ea_set_segment($$, 0);
+    }
+    | REG_CS ':' memaddr    { $$ = $3; x86_ea_set_segment($$, 0x2E); }
+    | REG_SS ':' memaddr    { $$ = $3; x86_ea_set_segment($$, 0x36); }
+    | REG_DS ':' memaddr    { $$ = $3; x86_ea_set_segment($$, 0x3E); }
+    | REG_ES ':' memaddr    { $$ = $3; x86_ea_set_segment($$, 0x26); }
+    | REG_FS ':' memaddr    { $$ = $3; x86_ea_set_segment($$, 0x64); }
+    | REG_GS ':' memaddr    { $$ = $3; x86_ea_set_segment($$, 0x65); }
+    | BYTE memaddr	    { $$ = $2; ea_set_len($$, 1); }
+    | WORD memaddr	    { $$ = $2; ea_set_len($$, 2); }
+    | DWORD memaddr	    { $$ = $2; ea_set_len($$, 4); }
+    | NOSPLIT memaddr	    { $$ = $2; ea_set_nosplit($$, 1); }
 ;
 
 mem: '[' memaddr ']'	{ $$ = $2; }
@@ -378,43 +379,43 @@ mem1632: mem
 ;
 
 /* explicit register or memory */
-rm8x: reg8	{ $$ = effaddr_new_reg($1); }
+rm8x: reg8	{ $$ = x86_ea_new_reg($1); }
     | mem8x
 ;
-rm16x: reg16	{ $$ = effaddr_new_reg($1); }
+rm16x: reg16	{ $$ = x86_ea_new_reg($1); }
     | mem16x
 ;
-rm32x: reg32	{ $$ = effaddr_new_reg($1); }
+rm32x: reg32	{ $$ = x86_ea_new_reg($1); }
     | mem32x
 ;
 /* not needed:
-rm64x: MMXREG	{ $$ = effaddr_new_reg($1); }
+rm64x: MMXREG	{ $$ = x86_ea_new_reg($1); }
     | mem64x
 ;
-rm128x: XMMREG	{ $$ = effaddr_new_reg($1); }
+rm128x: XMMREG	{ $$ = x86_ea_new_reg($1); }
     | mem128x
 ;
 */
 
 /* implicit register or memory */
-rm8: reg8	{ $$ = effaddr_new_reg($1); }
+rm8: reg8	{ $$ = x86_ea_new_reg($1); }
     | mem8
 ;
-rm16: reg16	{ $$ = effaddr_new_reg($1); }
+rm16: reg16	{ $$ = x86_ea_new_reg($1); }
     | mem16
 ;
-rm32: reg32	{ $$ = effaddr_new_reg($1); }
+rm32: reg32	{ $$ = x86_ea_new_reg($1); }
     | mem32
 ;
-rm64: MMXREG	{ $$ = effaddr_new_reg($1); }
+rm64: MMXREG	{ $$ = x86_ea_new_reg($1); }
     | mem64
 ;
-rm128: XMMREG	{ $$ = effaddr_new_reg($1); }
+rm128: XMMREG	{ $$ = x86_ea_new_reg($1); }
     | mem128
 ;
 
 /* immediate values */
-imm: expr   { $$ = immval_new_expr($1); }
+imm: expr   { $$ = imm_new_expr($1); }
 ;
 
 /* explicit immediates */
@@ -437,9 +438,18 @@ imm32: imm
 ;
 
 /* jump targets */
-target: expr		{ $$.val = $1; SetOpcodeSel(&$$.op_sel, JR_NONE); }
-    | SHORT target	{ $$ = $2; SetOpcodeSel(&$$.op_sel, JR_SHORT_FORCED); }
-    | NEAR target	{ $$ = $2; SetOpcodeSel(&$$.op_sel, JR_NEAR_FORCED); }
+target: expr		{
+	$$.val = $1;
+	x86_set_jmprel_opcode_sel(&$$.op_sel, JR_NONE);
+    }
+    | SHORT target	{
+	$$ = $2;
+	x86_set_jmprel_opcode_sel(&$$.op_sel, JR_SHORT_FORCED);
+    }
+    | NEAR target	{
+	$$ = $2;
+	x86_set_jmprel_opcode_sel(&$$.op_sel, JR_NEAR_FORCED);
+    }
 ;
 
 /* expression trees */
@@ -493,18 +503,36 @@ explabel: ID		{ $$ = symrec_use($1); xfree($1); }
 ;
 
 instr: instrbase
-    | OPERSIZE instr	{ $$ = $2; SetInsnOperSizeOverride($$, $1); }
-    | ADDRSIZE instr	{ $$ = $2; SetInsnAddrSizeOverride($$, $1); }
-    | REG_CS instr	{ $$ = $2; SetEASegment(GetInsnEA($$), 0x2E); }
-    | REG_SS instr	{ $$ = $2; SetEASegment(GetInsnEA($$), 0x36); }
-    | REG_DS instr	{ $$ = $2; SetEASegment(GetInsnEA($$), 0x3E); }
-    | REG_ES instr	{ $$ = $2; SetEASegment(GetInsnEA($$), 0x26); }
-    | REG_FS instr	{ $$ = $2; SetEASegment(GetInsnEA($$), 0x64); }
-    | REG_GS instr	{ $$ = $2; SetEASegment(GetInsnEA($$), 0x65); }
-    | LOCK instr	{ $$ = $2; SetInsnLockRepPrefix($$, 0xF0); }
-    | REPNZ instr	{ $$ = $2; SetInsnLockRepPrefix($$, 0xF2); }
-    | REP instr		{ $$ = $2; SetInsnLockRepPrefix($$, 0xF3); }
-    | REPZ instr	{ $$ = $2; SetInsnLockRepPrefix($$, 0xF4); }
+    | OPERSIZE instr	{ $$ = $2; x86_bc_insn_opersize_override($$, $1); }
+    | ADDRSIZE instr	{ $$ = $2; x86_bc_insn_addrsize_override($$, $1); }
+    | REG_CS instr	{
+	$$ = $2;
+	x86_ea_set_segment(x86_bc_insn_get_ea($$), 0x2E);
+    }
+    | REG_SS instr	{
+	$$ = $2;
+	x86_ea_set_segment(x86_bc_insn_get_ea($$), 0x36);
+    }
+    | REG_DS instr	{
+	$$ = $2;
+	x86_ea_set_segment(x86_bc_insn_get_ea($$), 0x3E);
+    }
+    | REG_ES instr	{
+	$$ = $2;
+	x86_ea_set_segment(x86_bc_insn_get_ea($$), 0x26);
+    }
+    | REG_FS instr	{
+	$$ = $2;
+	x86_ea_set_segment(x86_bc_insn_get_ea($$), 0x64);
+    }
+    | REG_GS instr	{
+	$$ = $2;
+	x86_ea_set_segment(x86_bc_insn_get_ea($$), 0x65);
+    }
+    | LOCK instr	{ $$ = $2; x86_bc_insn_set_lockrep_prefix($$, 0xF0); }
+    | REPNZ instr	{ $$ = $2; x86_bc_insn_set_lockrep_prefix($$, 0xF2); }
+    | REP instr		{ $$ = $2; x86_bc_insn_set_lockrep_prefix($$, 0xF3); }
+    | REPZ instr	{ $$ = $2; x86_bc_insn_set_lockrep_prefix($$, 0xF4); }
 ;
 
 /* instruction grammars (dynamically generated) */
@@ -528,7 +556,7 @@ nasm_parser_directive(const char *name, const char *val)
 	if (*val == '\0' || *end != '\0' || (lval != 16 && lval != 32))
 	    Error(_("`%s' is not a valid argument to [BITS]"), val);
 	else
-	    mode_bits = (unsigned char)lval;
+	    x86_mode_bits = (unsigned char)lval;
     } else {
 	printf("Directive: Name=`%s' Value=`%s'\n", name, val);
     }
diff --git a/modules/parsers/nasm/gen_instr.pl b/modules/parsers/nasm/gen_instr.pl
index adaa58db..be391260 100755
--- a/modules/parsers/nasm/gen_instr.pl
+++ b/modules/parsers/nasm/gen_instr.pl
@@ -353,7 +353,8 @@ sub cond_action_if ( $ $ $ $ $ $ $ )
     my ($rule, $tokens, $count, $regarg, $val, $func, $a_eax) = splice (@_);
     return rule_header ($rule, $tokens, $count) . <<"EOF";
         if (\$$regarg == $val) {
-            \$\$ = $func(@$a_eax);
+            @$a_eax
+            \$\$ = $func;
         }
 EOF
 }
@@ -362,7 +363,8 @@ sub cond_action_elsif ( $ $ $ $ )
     my ($regarg, $val, $func, $a_eax) = splice (@_);
     return <<"EOF";
         else if (\$$regarg == $val) {
-            \$\$ = $func(@$a_eax);
+            @$a_eax
+            \$\$ = $func;
         }
 EOF
 }
@@ -371,7 +373,8 @@ sub cond_action_else ( $ $ )
     my ($func, $a_args) = splice (@_);
     return <<"EOF" . rule_footer;
         else {
-            \$\$ = $func (@$a_args);
+            @$a_args
+            \$\$ = $func;
         }
 EOF
 }
@@ -388,7 +391,8 @@ sub action ( @ $ )
 {
     my ($rule, $tokens, $func, $a_args, $count) = splice @_;
     return rule_header ($rule, $tokens, $count)
-	. "        \$\$ = $func (@$a_args);\n"
+	. "        @$a_args\n"
+	. "        \$\$ = $func;\n"
 	. rule_footer; 
 }
 
@@ -396,8 +400,9 @@ sub action_setshiftflag ( @ $ )
 {
     my ($rule, $tokens, $func, $a_args, $count) = splice @_;
     return rule_header ($rule, $tokens, $count)
-	. "        \$\$ = $func (@$a_args);\n"
-	. "        SetInsnShiftFlag(\$\$);\n"
+	. "        @$a_args\n"
+	. "        \$\$ = $func;\n"
+	. "        x86_bc_insn_set_shift_flag(\$\$);\n"
 	. rule_footer; 
 }
 
@@ -421,7 +426,12 @@ sub output_yacc ($@)
 
     while (<IN>)
     {
-	if (m{/[*]\s*[@]TOKENS[@]\s*[*]/})
+	if (m{/[*]\s*[@]DATADECLS[@]\s*[*]/})
+	{
+	    print GRAMMAR "static x86_new_insn_data idata;\n";
+	    print GRAMMAR "static x86_new_jmprel_data jrdata;\n";
+	}
+	elsif (m{/[*]\s*[@]TOKENS[@]\s*[*]/})
 	{
 	    my $len = length("%token <groupdata>");
 	    print GRAMMAR "%token <groupdata>";
@@ -500,69 +510,82 @@ sub output_yacc ($@)
 			    if $inst->[OPERANDS] ne 'nil';
 			$tokens =~ s/,/ ',' /g;
 			$tokens =~ s/:/ ':' /g;
-			my $func = "bytecode_new_jmprel";
+			my $datastruct = "x86_new_jmprel_data";
+			my $datastructname = "jrdata";
+			my $func = "x86_bc_new_jmprel(&$datastructname)";
 
 			# Create the argument list for bytecode_new
 			my @args;
 
 			# Target argument: HACK: Always assumed to be arg 1.
-			push @args, '&$2,';
+			push @args, 'target=&$2;';
 
 			# test for short opcode "nil"
 			if($inst->[SHORTOPCODE] =~ m/nil/)
 			{
-			    push @args, '0, 0, 0, 0,';
+			    push @args, 'short_op_len=0;';
+			    push @args, 'short_op[0]=0;';
+			    push @args, 'short_op[1]=0;';
+			    push @args, 'short_op[2]=0;';
 			}
 			else
 			{
-			    # number of bytes of short opcode
-			    push @args, (scalar(()=$inst->[SHORTOPCODE] =~ m/(,)/)+1) . ",";
-
 			    # opcode piece 1 (and 2 and 3 if attached)
-			    push @args, $inst->[SHORTOPCODE];
-			    $args[-1] =~ s/,/, /;
-			    $args[-1] =~ s/([0-9A-Fa-f]{2})/0x$1/g;
-			    # don't match $0.\d in the following rule.
-			    $args[-1] =~ s/\$(\d+)(?!\.)/"\$" . ($1*2)/eg;
-			    $args[-1] .= ',';
+			    my @opcodes = split ",", $inst->[SHORTOPCODE];
+			    # number of bytes of short opcode
+			    push @args, "short_op_len=".@opcodes.";";
+			    for (my $i=0; $i < @opcodes; ++$i)
+			    {
+				$opcodes[$i] =~ s/([0-9A-Fa-f]{2})/0x$1/g;
+				# don't match $0.\d in the following rule.
+				$opcodes[$i] =~ s/\$(\d+)(?!\.)/"\$".($1*2)/eg;
+				push @args, "short_op[$i]=$opcodes[$i];";
+			    }
 
 			    # opcode piece 2 (if not attached)
-			    push @args, "0," if $inst->[SHORTOPCODE] !~ m/,/o;
+			    push @args, "short_op[1]=0;" if @opcodes < 2;
 			    # opcode piece 3 (if not attached)
-			    push @args, "0," if $inst->[SHORTOPCODE] !~ m/,.*,/o;
+			    push @args, "short_op[2]=0;" if @opcodes < 3;
 			}
 
 			# test for near opcode "nil"
 			if($inst->[NEAROPCODE] =~ m/nil/)
 			{
-			    push @args, '0, 0, 0, 0,';
+			    push @args, 'near_op_len=0;';
+			    push @args, 'near_op[0]=0;';
+			    push @args, 'near_op[1]=0;';
+			    push @args, 'near_op[2]=0;';
 			}
 			else
 			{
-			    # number of bytes of near opcode
-			    push @args, (scalar(()=$inst->[NEAROPCODE] =~ m/(,)/)+1) . ",";
-
 			    # opcode piece 1 (and 2 and 3 if attached)
-			    push @args, $inst->[NEAROPCODE];
-			    $args[-1] =~ s/,/, /;
-			    $args[-1] =~ s/([0-9A-Fa-f]{2})/0x$1/g;
-			    # don't match $0.\d in the following rule.
-			    $args[-1] =~ s/\$(\d+)(?!\.)/"\$" . ($1*2)/eg;
-			    $args[-1] .= ',';
+			    my @opcodes = split ",", $inst->[NEAROPCODE];
+			    # number of bytes of near opcode
+			    push @args, "near_op_len=".@opcodes.";";
+			    for (my $i=0; $i < @opcodes; ++$i)
+			    {
+				$opcodes[$i] =~ s/([0-9A-Fa-f]{2})/0x$1/g;
+				# don't match $0.\d in the following rule.
+				$opcodes[$i] =~ s/\$(\d+)(?!\.)/"\$".($1*2)/eg;
+				push @args, "near_op[$i]=$opcodes[$i];";
+			    }
 
 			    # opcode piece 2 (if not attached)
-			    push @args, "0," if $inst->[NEAROPCODE] !~ m/,/o;
+			    push @args, "near_op[1]=0;" if @opcodes < 2;
 			    # opcode piece 3 (if not attached)
-			    push @args, "0," if $inst->[NEAROPCODE] !~ m/,.*,/o;
+			    push @args, "near_op[2]=0;" if @opcodes < 3;
 			}
 
 			# address size
-			push @args, "$inst->[ADSIZE]";
+			push @args, "addrsize=$inst->[ADSIZE];";
 			$args[-1] =~ s/nil/0/;
 
 			# now that we've constructed the arglist, subst $0.\d
 			s/\$0\.(\d+)/\$1\[$1\]/g foreach (@args);
 
+			# and add the data structure reference
+			s/^/$datastructname./g foreach (@args);
+
 			# generate the grammar
 			print GRAMMAR action ($rule, $tokens, $func, \@args, $count++);
 		    }
@@ -583,65 +606,79 @@ sub output_yacc ($@)
 			$tokens =~ s/:/ ':' /g;
 			# offset args
 			my $to = $tokens =~ m/\b(TO|WORD|DWORD)\b/ ? 1 : 0;
-			my $func = "bytecode_new_insn";
+			my $datastruct = "x86_new_insn_data";
+			my $datastructname = "idata";
+			my $func = "x86_bc_new_insn(&$datastructname)";
 
 			# Create the argument list for bytecode_new
 			my @args;
 
 			# operand size
-			push @args, "$inst->[OPSIZE],";
+			push @args, "opersize=$inst->[OPSIZE];";
 			$args[-1] =~ s/nil/0/;
 
-			# number of bytes of opcodes
-			push @args, (scalar(()=$inst->[OPCODE] =~ m/(,)/)+1) . ",";
 
 			# opcode piece 1 (and 2 and 3 if attached)
-			push @args, $inst->[OPCODE];
-			$args[-1] =~ s/,/, /;
-			$args[-1] =~ s/([0-9A-Fa-f]{2})/0x$1/g;
-			# don't match $0.\d in the following rule.
-			$args[-1] =~ s/\$(\d+)(?!\.)/"\$" . ($1*2+$to)/eg;
-			$args[-1] .= ',';
+			my @opcodes = split ",", $inst->[OPCODE];
+			# number of bytes of opcodes
+			push @args, "op_len=".@opcodes.";";
+			for (my $i=0; $i < @opcodes; ++$i)
+			{
+			    $opcodes[$i] =~ s/([0-9A-Fa-f]{2})/0x$1/g;
+			    # don't match $0.\d in the following rule.
+			    $opcodes[$i] =~ s/\$(\d+)(?!\.)/"\$".($1*2+$to)/eg;
+			    push @args, "op[$i]=$opcodes[$i];";
+			}
 
 			# opcode piece 2 (if not attached)
-			push @args, "0," if $inst->[OPCODE] !~ m/,/o;
+			push @args, "op[1]=0;" if @opcodes < 2;
 			# opcode piece 3 (if not attached)
-			push @args, "0," if $inst->[OPCODE] !~ m/,.*,/o;
+			push @args, "op[2]=0;" if @opcodes < 3;
 
 			# effective addresses
-			push @args, $inst->[EFFADDR];
-			$args[-1] =~ s/,/, /;
-			$args[-1] =~ s/^nil$/(effaddr *)NULL, 0/;
-			$args[-1] =~ s/nil/0/;
+			my $effaddr = $inst->[EFFADDR];
+			$effaddr =~ s/^nil/(effaddr *)NULL,0/;
+			$effaddr =~ s/nil/0/;
 			# don't let a $0.\d match slip into the following rules.
-			$args[-1] =~ s/\$(\d+)([ri])?(?!\.)/"\$".($1*2+$to).($2||'')/eg;
+			$effaddr =~ s/\$(\d+)([ri])?(?!\.)/"\$".($1*2+$to).($2||'')/eg;
 			#$args[-1] =~ s/(\$\d+[ri]?)(?!\.)/\&$1/; # Just the first!
-			$args[-1] =~ s/(\$\d+)r/effaddr_new_reg($1)/;
-			$args[-1] =~ s[(\$\d+)i,\s*(\d+)]
-			    ["effaddr_new_imm($1, ".($2/8)."), 0"]e;
-			$args[-1] .= ',';
+			$effaddr =~ s/(\$\d+)r/x86_ea_new_reg($1)/;
+			$effaddr =~ s[(\$\d+)i,\s*(\d+)]
+			    ["x86_ea_new_imm($1^ ".($2/8)."),0"]e;
 
-			die $args[-1] if $args[-1] =~ m/\d+[ri]/;
+			die $effaddr if $effaddr =~ m/\d+[ri]/;
+
+			my @effaddr_split = split ',', $effaddr;
+			$effaddr_split[0] =~ s/\^/,/;
+			push @args, "ea=$effaddr_split[0];";
+			push @args, "spare=$effaddr_split[1];";
 
 			# immediate sources
-			push @args, $inst->[IMM];
-			$args[-1] =~ s/,/, /;
-			$args[-1] =~ s/nil/(immval *)NULL, 0/;
+			my $imm = $inst->[IMM];
+			$imm =~ s/nil/(immval *)NULL,0/;
 			# don't match $0.\d in the following rules.
-			$args[-1] =~ s/\$(\d+)(?!\.)/"\$".($1*2+$to).($2||'')/eg;
-			$args[-1] =~ s[^([0-9A-Fa-f]+),]
-			    [immval_new_int(0x$1),];
-			$args[-1] =~ s[^\$0.(\d+),]
-			    [immval_new_int(\$1\[$1\]),];
+			$imm =~ s/\$(\d+)(?!\.)/"\$".($1*2+$to).($2||'')/eg;
+			$imm =~ s[^([0-9A-Fa-f]+),]
+			    [imm_new_int(0x$1),];
+			$imm =~ s[^\$0.(\d+),]
+			    [imm_new_int(\$1\[$1\]),];
 
 			# divide the second, and only the second, by 8 bits/byte
-			$args[-1] =~ s#(,\s*)(\d+)(s)?#$1 . ($2/8)#eg;
-			$args[-1] .= ($3||'') eq 's' ? ', 1' : ', 0';
+			$imm =~ s#(,\s*)(\d+)(s)?#$1 . ($2/8)#eg;
+			$imm .= ($3||'') eq 's' ? ',1' : ',0';
+
+			die $imm if $imm =~ m/\d+s/;
 
-			die $args[-1] if $args[-1] =~ m/\d+s/;
+			my @imm_split = split ",", $imm;
+			push @args, "imm=$imm_split[0];";
+			push @args, "im_len=$imm_split[1];";
+			push @args, "im_sign=$imm_split[2];";
 
 			# now that we've constructed the arglist, subst $0.\d
 			s/\$0\.(\d+)/\$1\[$1\]/g foreach (@args);
+
+			# and add the data structure reference
+			s/^/$datastructname./g foreach (@args);
 		    
 			# see if we match one of the cases to defer
 			if (($inst->[OPERANDS]||"") =~ m/,ONE/)
@@ -691,8 +728,9 @@ sub output_yacc ($@)
 			    # Now output imm version, with second opcode byte
 			    # set to ,1 opcode.  Also call SetInsnShiftFlag().
 			    $tokens =~ s/imm8x/imm/;
-			    die "no space for ONE?" if $args[3] !~ m/0,/;
-			    $args[3] = $ONE->[3]->[2];
+			    die "no space for ONE?" if $args[3] !~ m/0;/;
+			    my $oneval = $ONE->[3]->[2];
+			    $args[3] =~ s/0/$oneval/;
 			    print GRAMMAR action_setshiftflag ($rule, $tokens, $func, \@args, $count++);
 			}
 			elsif ($AL and ($inst->[OPERANDS]||"") =~ m/reg8,imm/)
diff --git a/modules/parsers/nasm/nasm-bison.y b/modules/parsers/nasm/nasm-bison.y
index 54893a76..fa318fd3 100644
--- a/modules/parsers/nasm/nasm-bison.y
+++ b/modules/parsers/nasm/nasm-bison.y
@@ -40,6 +40,7 @@ RCSID("$IdPath$");
 #include "section.h"
 #include "objfmt.h"
 
+#include "arch.h"
 
 #define YYDEBUG 1
 
@@ -56,6 +57,9 @@ extern char *nasm_parser_locallabel_base;
 static bytecode *nasm_parser_prev_bc = (bytecode *)NULL;
 static bytecode *nasm_parser_temp_bc;
 
+/* additional data declarations (dynamically generated) */
+/* @DATADECLS@ */
+
 %}
 
 %union {
@@ -68,7 +72,7 @@ static bytecode *nasm_parser_temp_bc;
     effaddr *ea;
     expr *exp;
     immval *im_val;
-    targetval tgt_val;
+    x86_targetval tgt_val;
     datavalhead datahead;
     dataval *data;
     bytecode *bc;
@@ -126,7 +130,7 @@ static bytecode *nasm_parser_temp_bc;
 %%
 input: /* empty */
     | input line    {
-	nasm_parser_temp_bc = bytecodes_append(section_get_bytecodes(nasm_parser_cur_section),
+	nasm_parser_temp_bc = bcs_append(section_get_bytecodes(nasm_parser_cur_section),
 					       $2);
 	if (nasm_parser_temp_bc)
 	    nasm_parser_prev_bc = nasm_parser_temp_bc;
@@ -145,10 +149,10 @@ line: '\n'		{ $$ = (bytecode *)NULL; }
 ;
 
 lineexp: exp
-    | TIMES expr exp			{ $$ = $3; SetBCMultiple($$, $2); }
+    | TIMES expr exp			{ $$ = $3; bc_set_multiple($$, $2); }
     | label				{ $$ = (bytecode *)NULL; }
     | label exp				{ $$ = $2; }
-    | label TIMES expr exp		{ $$ = $4; SetBCMultiple($$, $3); }
+    | label TIMES expr exp		{ $$ = $4; bc_set_multiple($$, $3); }
     | label_id EQU expr			{
 	symrec_define_equ($1, $3);
 	xfree($1);
@@ -157,22 +161,16 @@ lineexp: exp
 ;
 
 exp: instr
-    | DECLARE_DATA datavals	    { $$ = bytecode_new_data(&$2, $1); }
-    | RESERVE_SPACE expr	    { $$ = bytecode_new_reserve($2, $1); }
+    | DECLARE_DATA datavals	    { $$ = bc_new_data(&$2, $1); }
+    | RESERVE_SPACE expr	    { $$ = bc_new_reserve($2, $1); }
 ;
 
-datavals: dataval	    {
-	datavals_initialize(&$$);
-	datavals_append(&$$, $1);
-    }
-    | datavals ',' dataval  {
-	datavals_append(&$1, $3);
-	$$ = $1;
-    }
+datavals: dataval	    { dvs_initialize(&$$); dvs_append(&$$, $1); }
+    | datavals ',' dataval  { dvs_append(&$1, $3); $$ = $1; }
 ;
 
-dataval: expr_no_string	{ $$ = dataval_new_expr($1); }
-    | STRING		{ $$ = dataval_new_string($1); }
+dataval: expr_no_string	{ $$ = dv_new_expr($1); }
+    | STRING		{ $$ = dv_new_string($1); }
     | error		{
 	Error(_("expression syntax error"));
 	$$ = (dataval *)NULL;
@@ -317,17 +315,20 @@ memexpr: INTNUM			{ $$ = expr_new_ident(ExprInt($1)); }
     | error			{ Error(_("invalid effective address")); }
 ;
 
-memaddr: memexpr	    { $$ = effaddr_new_expr($1); SetEASegment($$, 0); }
-    | REG_CS ':' memaddr    { $$ = $3; SetEASegment($$, 0x2E); }
-    | REG_SS ':' memaddr    { $$ = $3; SetEASegment($$, 0x36); }
-    | REG_DS ':' memaddr    { $$ = $3; SetEASegment($$, 0x3E); }
-    | REG_ES ':' memaddr    { $$ = $3; SetEASegment($$, 0x26); }
-    | REG_FS ':' memaddr    { $$ = $3; SetEASegment($$, 0x64); }
-    | REG_GS ':' memaddr    { $$ = $3; SetEASegment($$, 0x65); }
-    | BYTE memaddr	    { $$ = $2; SetEALen($$, 1); }
-    | WORD memaddr	    { $$ = $2; SetEALen($$, 2); }
-    | DWORD memaddr	    { $$ = $2; SetEALen($$, 4); }
-    | NOSPLIT memaddr	    { $$ = $2; SetEANosplit($$, 1); }
+memaddr: memexpr	    {
+	$$ = x86_ea_new_expr($1);
+	x86_ea_set_segment($$, 0);
+    }
+    | REG_CS ':' memaddr    { $$ = $3; x86_ea_set_segment($$, 0x2E); }
+    | REG_SS ':' memaddr    { $$ = $3; x86_ea_set_segment($$, 0x36); }
+    | REG_DS ':' memaddr    { $$ = $3; x86_ea_set_segment($$, 0x3E); }
+    | REG_ES ':' memaddr    { $$ = $3; x86_ea_set_segment($$, 0x26); }
+    | REG_FS ':' memaddr    { $$ = $3; x86_ea_set_segment($$, 0x64); }
+    | REG_GS ':' memaddr    { $$ = $3; x86_ea_set_segment($$, 0x65); }
+    | BYTE memaddr	    { $$ = $2; ea_set_len($$, 1); }
+    | WORD memaddr	    { $$ = $2; ea_set_len($$, 2); }
+    | DWORD memaddr	    { $$ = $2; ea_set_len($$, 4); }
+    | NOSPLIT memaddr	    { $$ = $2; ea_set_nosplit($$, 1); }
 ;
 
 mem: '[' memaddr ']'	{ $$ = $2; }
@@ -378,43 +379,43 @@ mem1632: mem
 ;
 
 /* explicit register or memory */
-rm8x: reg8	{ $$ = effaddr_new_reg($1); }
+rm8x: reg8	{ $$ = x86_ea_new_reg($1); }
     | mem8x
 ;
-rm16x: reg16	{ $$ = effaddr_new_reg($1); }
+rm16x: reg16	{ $$ = x86_ea_new_reg($1); }
     | mem16x
 ;
-rm32x: reg32	{ $$ = effaddr_new_reg($1); }
+rm32x: reg32	{ $$ = x86_ea_new_reg($1); }
     | mem32x
 ;
 /* not needed:
-rm64x: MMXREG	{ $$ = effaddr_new_reg($1); }
+rm64x: MMXREG	{ $$ = x86_ea_new_reg($1); }
     | mem64x
 ;
-rm128x: XMMREG	{ $$ = effaddr_new_reg($1); }
+rm128x: XMMREG	{ $$ = x86_ea_new_reg($1); }
     | mem128x
 ;
 */
 
 /* implicit register or memory */
-rm8: reg8	{ $$ = effaddr_new_reg($1); }
+rm8: reg8	{ $$ = x86_ea_new_reg($1); }
     | mem8
 ;
-rm16: reg16	{ $$ = effaddr_new_reg($1); }
+rm16: reg16	{ $$ = x86_ea_new_reg($1); }
     | mem16
 ;
-rm32: reg32	{ $$ = effaddr_new_reg($1); }
+rm32: reg32	{ $$ = x86_ea_new_reg($1); }
     | mem32
 ;
-rm64: MMXREG	{ $$ = effaddr_new_reg($1); }
+rm64: MMXREG	{ $$ = x86_ea_new_reg($1); }
     | mem64
 ;
-rm128: XMMREG	{ $$ = effaddr_new_reg($1); }
+rm128: XMMREG	{ $$ = x86_ea_new_reg($1); }
     | mem128
 ;
 
 /* immediate values */
-imm: expr   { $$ = immval_new_expr($1); }
+imm: expr   { $$ = imm_new_expr($1); }
 ;
 
 /* explicit immediates */
@@ -437,9 +438,18 @@ imm32: imm
 ;
 
 /* jump targets */
-target: expr		{ $$.val = $1; SetOpcodeSel(&$$.op_sel, JR_NONE); }
-    | SHORT target	{ $$ = $2; SetOpcodeSel(&$$.op_sel, JR_SHORT_FORCED); }
-    | NEAR target	{ $$ = $2; SetOpcodeSel(&$$.op_sel, JR_NEAR_FORCED); }
+target: expr		{
+	$$.val = $1;
+	x86_set_jmprel_opcode_sel(&$$.op_sel, JR_NONE);
+    }
+    | SHORT target	{
+	$$ = $2;
+	x86_set_jmprel_opcode_sel(&$$.op_sel, JR_SHORT_FORCED);
+    }
+    | NEAR target	{
+	$$ = $2;
+	x86_set_jmprel_opcode_sel(&$$.op_sel, JR_NEAR_FORCED);
+    }
 ;
 
 /* expression trees */
@@ -493,18 +503,36 @@ explabel: ID		{ $$ = symrec_use($1); xfree($1); }
 ;
 
 instr: instrbase
-    | OPERSIZE instr	{ $$ = $2; SetInsnOperSizeOverride($$, $1); }
-    | ADDRSIZE instr	{ $$ = $2; SetInsnAddrSizeOverride($$, $1); }
-    | REG_CS instr	{ $$ = $2; SetEASegment(GetInsnEA($$), 0x2E); }
-    | REG_SS instr	{ $$ = $2; SetEASegment(GetInsnEA($$), 0x36); }
-    | REG_DS instr	{ $$ = $2; SetEASegment(GetInsnEA($$), 0x3E); }
-    | REG_ES instr	{ $$ = $2; SetEASegment(GetInsnEA($$), 0x26); }
-    | REG_FS instr	{ $$ = $2; SetEASegment(GetInsnEA($$), 0x64); }
-    | REG_GS instr	{ $$ = $2; SetEASegment(GetInsnEA($$), 0x65); }
-    | LOCK instr	{ $$ = $2; SetInsnLockRepPrefix($$, 0xF0); }
-    | REPNZ instr	{ $$ = $2; SetInsnLockRepPrefix($$, 0xF2); }
-    | REP instr		{ $$ = $2; SetInsnLockRepPrefix($$, 0xF3); }
-    | REPZ instr	{ $$ = $2; SetInsnLockRepPrefix($$, 0xF4); }
+    | OPERSIZE instr	{ $$ = $2; x86_bc_insn_opersize_override($$, $1); }
+    | ADDRSIZE instr	{ $$ = $2; x86_bc_insn_addrsize_override($$, $1); }
+    | REG_CS instr	{
+	$$ = $2;
+	x86_ea_set_segment(x86_bc_insn_get_ea($$), 0x2E);
+    }
+    | REG_SS instr	{
+	$$ = $2;
+	x86_ea_set_segment(x86_bc_insn_get_ea($$), 0x36);
+    }
+    | REG_DS instr	{
+	$$ = $2;
+	x86_ea_set_segment(x86_bc_insn_get_ea($$), 0x3E);
+    }
+    | REG_ES instr	{
+	$$ = $2;
+	x86_ea_set_segment(x86_bc_insn_get_ea($$), 0x26);
+    }
+    | REG_FS instr	{
+	$$ = $2;
+	x86_ea_set_segment(x86_bc_insn_get_ea($$), 0x64);
+    }
+    | REG_GS instr	{
+	$$ = $2;
+	x86_ea_set_segment(x86_bc_insn_get_ea($$), 0x65);
+    }
+    | LOCK instr	{ $$ = $2; x86_bc_insn_set_lockrep_prefix($$, 0xF0); }
+    | REPNZ instr	{ $$ = $2; x86_bc_insn_set_lockrep_prefix($$, 0xF2); }
+    | REP instr		{ $$ = $2; x86_bc_insn_set_lockrep_prefix($$, 0xF3); }
+    | REPZ instr	{ $$ = $2; x86_bc_insn_set_lockrep_prefix($$, 0xF4); }
 ;
 
 /* instruction grammars (dynamically generated) */
@@ -528,7 +556,7 @@ nasm_parser_directive(const char *name, const char *val)
 	if (*val == '\0' || *end != '\0' || (lval != 16 && lval != 32))
 	    Error(_("`%s' is not a valid argument to [BITS]"), val);
 	else
-	    mode_bits = (unsigned char)lval;
+	    x86_mode_bits = (unsigned char)lval;
     } else {
 	printf("Directive: Name=`%s' Value=`%s'\n", name, val);
     }
diff --git a/modules/parsers/nasm/token.l.in b/modules/parsers/nasm/token.l.in
index 8c1d6834..54002180 100644
--- a/modules/parsers/nasm/token.l.in
+++ b/modules/parsers/nasm/token.l.in
@@ -33,6 +33,8 @@ RCSID("$IdPath$");
 
 #include "bytecode.h"
 
+#include "arch.h"
+
 #include "bison.h"
 
 
diff --git a/src/Makefile.am b/src/Makefile.am
index a1a4f899..0fbd211b 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -25,6 +25,7 @@ noinst_LIBRARIES = libyasm.a
 libyasm_a_SOURCES = \
 	bytecode.c		\
 	bytecode.h		\
+	bc-int.h		\
 	expr.c			\
 	expr.h			\
 	symrec.c		\
@@ -37,6 +38,7 @@ libyasm_a_SOURCES = \
 	file.h			\
 	section.c		\
 	section.h		\
+	arch.c			\
 	arch.h			\
 	objfmt.h		\
 	options.h		\
diff --git a/src/arch.c b/src/arch.c
new file mode 100644
index 00000000..5cbe3591
--- /dev/null
+++ b/src/arch.c
@@ -0,0 +1,29 @@
+/* $IdPath$
+ * Architecture interface
+ *
+ *  Copyright (C) 2001  Peter Johnson
+ *
+ *  This file is part of YASM.
+ *
+ *  YASM is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  YASM is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+#include "util.h"
+
+#include "bytecode.h"
+
+#include "arch.h"
+
+arch *cur_arch;
+
diff --git a/src/arch.h b/src/arch.h
index f1ed7268..b614aca4 100644
--- a/src/arch.h
+++ b/src/arch.h
@@ -28,9 +28,24 @@ struct arch {
 
     /* keyword used to select architecture */
     const char *keyword;
+
+    struct {
+	/* Maximum used bytecode type value+1.  Should be set to
+	 * BYTECODE_TYPE_BASE if no additional bytecode types are defined by
+	 * the architecture.
+	 */
+	const int type_max;
+
+	void (*bc_delete) (bytecode *bc);
+	void (*bc_print) (const bytecode *bc);
+	void (*bc_parser_finalize) (bytecode *bc);
+    } bc;
 };
 
 /* Available architectures */
+#include "arch/x86/x86arch.h"
 extern arch x86_arch;
 
+extern arch *cur_arch;
+
 #endif
diff --git a/src/arch/x86/Makefile.am b/src/arch/x86/Makefile.am
index 5847318c..5c5598d0 100644
--- a/src/arch/x86/Makefile.am
+++ b/src/arch/x86/Makefile.am
@@ -3,7 +3,10 @@
 noinst_LIBRARIES = libarch.a
 
 libarch_a_SOURCES = \
-	arch.c
+	x86arch.h	\
+	x86-int.h	\
+	arch.c		\
+	bytecode.c
 
 INCLUDES = \
 	-I$(top_srcdir)/src	\
diff --git a/src/arch/x86/arch.c b/src/arch/x86/arch.c
index a5df22fb..c9cf1cae 100644
--- a/src/arch/x86/arch.c
+++ b/src/arch/x86/arch.c
@@ -22,11 +22,22 @@
 #include "util.h"
 RCSID("$IdPath$");
 
+#include "bytecode.h"
 #include "arch.h"
 
+#include "x86-int.h"
+
+
+unsigned char x86_mode_bits = 0;
 
 /* Define arch structure -- see arch.h for details */
 arch x86_arch = {
     "x86 (IA-32, x86-64)",
-    "x86"
+    "x86",
+    {
+	X86_BYTECODE_TYPE_MAX,
+	x86_bc_delete,
+	x86_bc_print,
+	x86_bc_parser_finalize
+    }
 };
diff --git a/src/arch/x86/bytecode.c b/src/arch/x86/bytecode.c
new file mode 100644
index 00000000..80837116
--- /dev/null
+++ b/src/arch/x86/bytecode.c
@@ -0,0 +1,512 @@
+/*
+ * x86 architecture description
+ *
+ *  Copyright (C) 2001  Peter Johnson
+ *
+ *  This file is part of YASM.
+ *
+ *  YASM is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  YASM is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+#include "util.h"
+RCSID("$IdPath$");
+
+#include "errwarn.h"
+#include "intnum.h"
+#include "expr.h"
+
+#include "bytecode.h"
+#include "arch.h"
+
+#include "x86-int.h"
+
+#include "bc-int.h"
+
+
+bytecode *
+x86_bc_new_insn(x86_new_insn_data *d)
+{
+    bytecode *bc;
+    x86_insn *insn;
+   
+    bc = bc_new_common(X86_BC_INSN, sizeof(x86_insn));
+    insn = bc_get_data(bc);
+
+    insn->ea = d->ea;
+    if (d->ea) {
+	x86_effaddr_data *ead = ea_get_data(d->ea);
+	ead->modrm &= 0xC7;	/* zero spare/reg bits */
+	ead->modrm |= (d->spare << 3) & 0x38;	/* plug in provided bits */
+    }
+
+    insn->imm = d->imm;
+    if (d->imm) {
+	insn->imm->f_len = d->im_len;
+	insn->imm->f_sign = d->im_sign;
+    }
+
+    insn->opcode[0] = d->op[0];
+    insn->opcode[1] = d->op[1];
+    insn->opcode[2] = d->op[2];
+    insn->opcode_len = d->op_len;
+
+    insn->addrsize = 0;
+    insn->opersize = d->opersize;
+    insn->lockrep_pre = 0;
+    insn->shift_op = 0;
+
+    insn->mode_bits = x86_mode_bits;
+
+    return bc;
+}
+
+bytecode *
+x86_bc_new_jmprel(x86_new_jmprel_data *d)
+{
+    bytecode *bc;
+    x86_jmprel *jmprel;
+
+    bc = bc_new_common(X86_BC_JMPREL, sizeof(x86_jmprel));
+    jmprel = bc_get_data(bc);
+
+    jmprel->target = d->target->val;
+    jmprel->op_sel = d->target->op_sel;
+
+    if ((d->target->op_sel == JR_SHORT_FORCED) && (d->near_op_len == 0))
+	Error(_("no SHORT form of that jump instruction exists"));
+    if ((d->target->op_sel == JR_NEAR_FORCED) && (d->short_op_len == 0))
+	Error(_("no NEAR form of that jump instruction exists"));
+
+    jmprel->shortop.opcode[0] = d->short_op[0];
+    jmprel->shortop.opcode[1] = d->short_op[1];
+    jmprel->shortop.opcode[2] = d->short_op[2];
+    jmprel->shortop.opcode_len = d->short_op_len;
+
+    jmprel->nearop.opcode[0] = d->near_op[0];
+    jmprel->nearop.opcode[1] = d->near_op[1];
+    jmprel->nearop.opcode[2] = d->near_op[2];
+    jmprel->nearop.opcode_len = d->near_op_len;
+
+    jmprel->addrsize = d->addrsize;
+    jmprel->opersize = 0;
+    jmprel->lockrep_pre = 0;
+
+    jmprel->mode_bits = x86_mode_bits;
+
+    return bc;
+}
+
+void
+x86_ea_set_segment(effaddr *ea, unsigned char segment)
+{
+    x86_effaddr_data *ead;
+
+    if (!ea)
+	return;
+
+    ead = ea_get_data(ea);
+
+    if (segment != 0 && ead->segment != 0)
+	Warning(_("multiple segment overrides, using leftmost"));
+
+    ead->segment = segment;
+}
+
+effaddr *
+x86_ea_new_reg(unsigned long reg)
+{
+    effaddr *ea = xmalloc(sizeof(effaddr)+sizeof(x86_effaddr_data));
+    x86_effaddr_data *ead = ea_get_data(ea);
+
+    ea->disp = (expr *)NULL;
+    ea->len = 0;
+    ea->nosplit = 0;
+    ead->segment = 0;
+    ead->modrm = 0xC0 | (reg & 0x07);	/* Mod=11, R/M=Reg, Reg=0 */
+    ead->valid_modrm = 1;
+    ead->need_modrm = 1;
+    ead->valid_sib = 0;
+    ead->need_sib = 0;
+
+    return ea;
+}
+
+effaddr *
+x86_ea_new_expr(expr *e)
+{
+    effaddr *ea = xmalloc(sizeof(effaddr)+sizeof(x86_effaddr_data));
+    x86_effaddr_data *ead = ea_get_data(ea);
+
+    ea->disp = e;
+    ea->len = 0;
+    ea->nosplit = 0;
+    ead->segment = 0;
+    ead->modrm = 0;
+    ead->valid_modrm = 0;
+    ead->need_modrm = 1;
+    ead->valid_sib = 0;
+    ead->need_sib = 0xff;   /* we won't know until we know more about expr and
+			       the BITS/address override setting */
+
+    return ea;
+}
+
+effaddr *
+x86_ea_new_imm(immval *imm, unsigned char im_len)
+{
+    effaddr *ea = xmalloc(sizeof(effaddr)+sizeof(x86_effaddr_data));
+    x86_effaddr_data *ead = ea_get_data(ea);
+
+    ea->disp = imm->val;
+    ea->len = im_len;
+    ea->nosplit = 0;
+    ead->segment = 0;
+    ead->modrm = 0;
+    ead->valid_modrm = 0;
+    ead->need_modrm = 0;
+    ead->valid_sib = 0;
+    ead->need_sib = 0;
+
+    return ea;
+}
+
+effaddr *
+x86_bc_insn_get_ea(bytecode *bc)
+{
+    x86_insn *insn = bc_get_data(bc);
+
+    if (!bc)
+	return NULL;
+
+    if (bc->type != X86_BC_INSN)
+	InternalError(_("Trying to get EA of non-instruction"));
+
+    return insn->ea;
+}
+
+void
+x86_bc_insn_opersize_override(bytecode *bc, unsigned char opersize)
+{
+    x86_insn *insn;
+    x86_jmprel *jmprel;
+
+    if (!bc)
+	return;
+
+    switch (bc->type) {
+	case X86_BC_INSN:
+	    insn = bc_get_data(bc);
+	    insn->opersize = opersize;
+	    break;
+	case X86_BC_JMPREL:
+	    jmprel = bc_get_data(bc);
+	    jmprel->opersize = opersize;
+	    break;
+	default:
+	    InternalError(_("OperSize override applied to non-instruction"));
+	    return;
+    }
+}
+
+void
+x86_bc_insn_addrsize_override(bytecode *bc, unsigned char addrsize)
+{
+    x86_insn *insn;
+    x86_jmprel *jmprel;
+
+    if (!bc)
+	return;
+
+    switch (bc->type) {
+	case X86_BC_INSN:
+	    insn = bc_get_data(bc);
+	    insn->addrsize = addrsize;
+	    break;
+	case X86_BC_JMPREL:
+	    jmprel = bc_get_data(bc);
+	    jmprel->addrsize = addrsize;
+	    break;
+	default:
+	    InternalError(_("AddrSize override applied to non-instruction"));
+	    return;
+    }
+}
+
+void
+x86_bc_insn_set_lockrep_prefix(bytecode *bc, unsigned char prefix)
+{
+    x86_insn *insn;
+    x86_jmprel *jmprel;
+    unsigned char *lockrep_pre = (unsigned char *)NULL;
+
+    if (!bc)
+	return;
+
+    switch (bc->type) {
+	case X86_BC_INSN:
+	    insn = bc_get_data(bc);
+	    lockrep_pre = &insn->lockrep_pre;
+	    break;
+	case X86_BC_JMPREL:
+	    jmprel = bc_get_data(bc);
+	    lockrep_pre = &jmprel->lockrep_pre;
+	    break;
+	default:
+	    InternalError(_("LockRep prefix applied to non-instruction"));
+	    return;
+    }
+
+    if (*lockrep_pre != 0)
+	Warning(_("multiple LOCK or REP prefixes, using leftmost"));
+
+    *lockrep_pre = prefix;
+}
+
+void
+x86_bc_insn_set_shift_flag(bytecode *bc)
+{
+    x86_insn *insn;
+
+    if (!bc)
+	return;
+
+    if (bc->type != X86_BC_INSN)
+	InternalError(_("Attempted to set shift flag on non-instruction"));
+
+    insn = bc_get_data(bc);
+
+    insn->shift_op = 1;
+}
+
+void
+x86_set_jmprel_opcode_sel(x86_jmprel_opcode_sel *old_sel,
+			  x86_jmprel_opcode_sel new_sel)
+{
+    if (!old_sel)
+	return;
+
+    if (new_sel != JR_NONE && ((*old_sel == JR_SHORT_FORCED) ||
+			       (*old_sel == JR_NEAR_FORCED)))
+	Warning(_("multiple SHORT or NEAR specifiers, using leftmost"));
+    *old_sel = new_sel;
+}
+
+void
+x86_bc_delete(bytecode *bc)
+{
+    x86_insn *insn;
+    x86_jmprel *jmprel;
+
+    switch ((x86_bytecode_type)bc->type) {
+	case X86_BC_INSN:
+	    insn = bc_get_data(bc);
+	    if (insn->ea) {
+		expr_delete(insn->ea->disp);
+		xfree(insn->ea);
+	    }
+	    if (insn->imm) {
+		expr_delete(insn->imm->val);
+		xfree(insn->imm);
+	    }
+	    break;
+	case X86_BC_JMPREL:
+	    jmprel = bc_get_data(bc);
+	    expr_delete(jmprel->target);
+	    break;
+    }
+}
+
+void
+x86_bc_print(const bytecode *bc)
+{
+    const x86_insn *insn;
+    const x86_jmprel *jmprel;
+    x86_effaddr_data *ead;
+
+    switch ((x86_bytecode_type)bc->type) {
+	case X86_BC_INSN:
+	    insn = bc_get_const_data(bc);
+	    printf("_Instruction_\n");
+	    printf("Effective Address:");
+	    if (!insn->ea)
+		printf(" (nil)\n");
+	    else {
+		printf("\n Disp=");
+		if (insn->ea->disp)
+		    expr_print(insn->ea->disp);
+		else
+		    printf("(nil)");
+		printf("\n");
+		ead = ea_get_data(insn->ea);
+		printf(" Len=%u SegmentOv=%02x NoSplit=%u\n",
+		       (unsigned int)insn->ea->len,
+		       (unsigned int)ead->segment,
+		       (unsigned int)insn->ea->nosplit);
+		printf(" ModRM=%03o ValidRM=%u NeedRM=%u\n",
+		       (unsigned int)ead->modrm,
+		       (unsigned int)ead->valid_modrm,
+		       (unsigned int)ead->need_modrm);
+		printf(" SIB=%03o ValidSIB=%u NeedSIB=%u\n",
+		       (unsigned int)ead->sib,
+		       (unsigned int)ead->valid_sib,
+		       (unsigned int)ead->need_sib);
+	    }
+	    printf("Immediate Value:");
+	    if (!insn->imm)
+		printf(" (nil)\n");
+	    else {
+		printf("\n Val=");
+		expr_print(insn->imm->val);
+		printf("\n");
+		printf(" Len=%u, IsNeg=%u\n",
+		       (unsigned int)insn->imm->len,
+		       (unsigned int)insn->imm->isneg);
+		printf(" FLen=%u, FSign=%u\n",
+		       (unsigned int)insn->imm->f_len,
+		       (unsigned int)insn->imm->f_sign);
+	    }
+	    printf("Opcode: %02x %02x %02x OpLen=%u\n",
+		   (unsigned int)insn->opcode[0],
+		   (unsigned int)insn->opcode[1],
+		   (unsigned int)insn->opcode[2],
+		   (unsigned int)insn->opcode_len);
+	    printf("AddrSize=%u OperSize=%u LockRepPre=%02x ShiftOp=%u\n",
+		   (unsigned int)insn->addrsize,
+		   (unsigned int)insn->opersize,
+		   (unsigned int)insn->lockrep_pre,
+		   (unsigned int)insn->shift_op);
+	    printf("BITS=%u\n", (unsigned int)insn->mode_bits);
+	    break;
+	case X86_BC_JMPREL:
+	    jmprel = bc_get_const_data(bc);
+	    printf("_Relative Jump_\n");
+	    printf("Target=");
+	    expr_print(jmprel->target);
+	    printf("\nShort Form:\n");
+	    if (!jmprel->shortop.opcode_len == 0)
+		printf(" None\n");
+	    else
+		printf(" Opcode: %02x %02x %02x OpLen=%u\n",
+		       (unsigned int)jmprel->shortop.opcode[0],
+		       (unsigned int)jmprel->shortop.opcode[1],
+		       (unsigned int)jmprel->shortop.opcode[2],
+		       (unsigned int)jmprel->shortop.opcode_len);
+	    if (!jmprel->nearop.opcode_len == 0)
+		printf(" None\n");
+	    else
+		printf(" Opcode: %02x %02x %02x OpLen=%u\n",
+		       (unsigned int)jmprel->nearop.opcode[0],
+		       (unsigned int)jmprel->nearop.opcode[1],
+		       (unsigned int)jmprel->nearop.opcode[2],
+		       (unsigned int)jmprel->nearop.opcode_len);
+	    printf("OpSel=");
+	    switch (jmprel->op_sel) {
+		case JR_NONE:
+		    printf("None");
+		    break;
+		case JR_SHORT:
+		    printf("Short");
+		    break;
+		case JR_NEAR:
+		    printf("Near");
+		    break;
+		case JR_SHORT_FORCED:
+		    printf("Forced Short");
+		    break;
+		case JR_NEAR_FORCED:
+		    printf("Forced Near");
+		    break;
+		default:
+		    printf("UNKNOWN!!");
+		    break;
+	    }
+	    printf("BITS=%u\nAddrSize=%u OperSize=%u LockRepPre=%02x\n",
+		   (unsigned int)jmprel->mode_bits,
+		   (unsigned int)jmprel->addrsize,
+		   (unsigned int)jmprel->opersize,
+		   (unsigned int)jmprel->lockrep_pre);
+	    break;
+    }
+}
+
+static void
+x86_bc_parser_finalize_insn(x86_insn *insn)
+{
+    effaddr *ea = insn->ea;
+    x86_effaddr_data *ead = ea_get_data(ea);
+    immval *imm = insn->imm;
+
+    if (ea) {
+	if ((ea->disp) && ((!ead->valid_sib && ead->need_sib) ||
+			   (!ead->valid_modrm && ead->need_modrm))) {
+	    /* First expand equ's */
+	    expr_expand_equ(ea->disp);
+
+	    /* Check validity of effective address and calc R/M bits of
+	     * Mod/RM byte and SIB byte.  We won't know the Mod field
+	     * of the Mod/RM byte until we know more about the
+	     * displacement.
+	     */
+	    if (!expr_checkea(&ea->disp, &insn->addrsize, insn->mode_bits,
+			      ea->nosplit, &ea->len, &ead->modrm,
+			      &ead->valid_modrm, &ead->need_modrm, &ead->sib,
+			      &ead->valid_sib, &ead->need_sib))
+		return;	    /* failed, don't bother checking rest of insn */
+	}
+    }
+
+    if (imm) {
+	const intnum *num;
+
+	if (imm->val) {
+	    expr_expand_equ(imm->val);
+	    expr_simplify(imm->val);
+	}
+	/* TODO: check imm f_len vs. len? */
+
+	/* Handle shift_op special-casing */
+	if (insn->shift_op && (num = expr_get_intnum(&imm->val))) {
+	    if (intnum_get_uint(num) == 1) {
+		/* Use ,1 form: first copy ,1 opcode. */
+		insn->opcode[0] = insn->opcode[1];
+		/* Delete ModRM, as it's no longer needed */
+		xfree(ea);
+		insn->ea = (effaddr *)NULL;
+		/* Delete Imm, as it's not needed */
+		expr_delete(imm->val);
+		xfree(imm);
+		insn->imm = (immval *)NULL;
+	    }
+	    insn->shift_op = 0;
+	}
+    }
+
+    
+}
+
+void
+x86_bc_parser_finalize(bytecode *bc)
+{
+    x86_insn *insn;
+
+    switch ((x86_bytecode_type)bc->type) {
+	case X86_BC_INSN:
+	    insn = bc_get_data(bc);
+	    x86_bc_parser_finalize_insn(insn);
+	    break;
+	default:
+	    break;
+    }
+}
+
diff --git a/src/arch/x86/x86-int.h b/src/arch/x86/x86-int.h
new file mode 100644
index 00000000..2c3336ee
--- /dev/null
+++ b/src/arch/x86/x86-int.h
@@ -0,0 +1,95 @@
+/* $IdPath$
+ * x86 internals header file
+ *
+ *  Copyright (C) 2001  Peter Johnson
+ *
+ *  This file is part of YASM.
+ *
+ *  YASM is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  YASM is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+#ifndef YASM_X86_INT_H
+#define YASM_X86_INT_H
+
+typedef struct x86_effaddr_data {
+    unsigned char segment;	/* segment override, 0 if none */
+
+    /* How the spare (register) bits in Mod/RM are handled:
+     * Even if valid_modrm=0, the spare bits are still valid (don't overwrite!)
+     * They're set in bytecode_new_insn().
+     */
+    unsigned char modrm;
+    unsigned char valid_modrm;	/* 1 if Mod/RM byte currently valid, 0 if not */
+    unsigned char need_modrm;	/* 1 if Mod/RM byte needed, 0 if not */
+
+    unsigned char sib;
+    unsigned char valid_sib;	/* 1 if SIB byte currently valid, 0 if not */
+    unsigned char need_sib;	/* 1 if SIB byte needed, 0 if not,
+				   0xff if unknown */
+} x86_effaddr_data;
+
+typedef struct x86_insn {
+    effaddr *ea;	/* effective address */
+
+    immval *imm;	/* immediate or relative value */
+
+    unsigned char opcode[3];	/* opcode */
+    unsigned char opcode_len;
+
+    unsigned char addrsize;	/* 0 or =mode_bits => no override */
+    unsigned char opersize;	/* 0 indicates no override */
+    unsigned char lockrep_pre;	/* 0 indicates no prefix */
+
+    /* HACK, but a space-saving one: shift opcodes have an immediate
+     * form and a ,1 form (with no immediate).  In the parser, we
+     * set this and opcode_len=1, but store the ,1 version in the
+     * second byte of the opcode array.  We then choose between the
+     * two versions once we know the actual value of imm (because we
+     * don't know it in the parser module).
+     *
+     * A override to force the imm version should just leave this at
+     * 0.  Then later code won't know the ,1 version even exists.
+     * TODO: Figure out how this affects CPU flags processing.
+     *
+     * Call x86_SetInsnShiftFlag() to set this flag to 1.
+     */
+    unsigned char shift_op;
+
+    unsigned char mode_bits;
+} x86_insn;
+
+typedef struct x86_jmprel {
+    expr *target;		/* target location */
+
+    struct {
+	unsigned char opcode[3];
+	unsigned char opcode_len;   /* 0 = no opc for this version */
+    } shortop, nearop;
+
+    /* which opcode are we using? */
+    /* The *FORCED forms are specified in the source as such */
+    x86_jmprel_opcode_sel op_sel;
+
+    unsigned char addrsize;	/* 0 or =mode_bits => no override */
+    unsigned char opersize;	/* 0 indicates no override */
+    unsigned char lockrep_pre;	/* 0 indicates no prefix */
+
+    unsigned char mode_bits;
+} x86_jmprel;
+
+void x86_bc_delete(bytecode *bc);
+void x86_bc_print(const bytecode *bc);
+void x86_bc_parser_finalize(bytecode *bc);
+
+#endif
diff --git a/src/arch/x86/x86arch.c b/src/arch/x86/x86arch.c
index a5df22fb..c9cf1cae 100644
--- a/src/arch/x86/x86arch.c
+++ b/src/arch/x86/x86arch.c
@@ -22,11 +22,22 @@
 #include "util.h"
 RCSID("$IdPath$");
 
+#include "bytecode.h"
 #include "arch.h"
 
+#include "x86-int.h"
+
+
+unsigned char x86_mode_bits = 0;
 
 /* Define arch structure -- see arch.h for details */
 arch x86_arch = {
     "x86 (IA-32, x86-64)",
-    "x86"
+    "x86",
+    {
+	X86_BYTECODE_TYPE_MAX,
+	x86_bc_delete,
+	x86_bc_print,
+	x86_bc_parser_finalize
+    }
 };
diff --git a/src/arch/x86/x86arch.h b/src/arch/x86/x86arch.h
new file mode 100644
index 00000000..70a207c1
--- /dev/null
+++ b/src/arch/x86/x86arch.h
@@ -0,0 +1,93 @@
+/* $IdPath$
+ * x86 Architecture header file
+ *
+ *  Copyright (C) 2001  Peter Johnson
+ *
+ *  This file is part of YASM.
+ *
+ *  YASM is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  YASM is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+#ifndef YASM_X86ARCH_H
+#define YASM_X86ARCH_H
+
+typedef enum {
+    X86_BC_INSN = BYTECODE_TYPE_BASE,
+    X86_BC_JMPREL
+} x86_bytecode_type;
+#define X86_BYTECODE_TYPE_MAX	X86_BC_JMPREL+1
+
+typedef enum {
+    JR_NONE,
+    JR_SHORT,
+    JR_NEAR,
+    JR_SHORT_FORCED,
+    JR_NEAR_FORCED
+} x86_jmprel_opcode_sel;
+
+typedef struct x86_targetval {
+    expr *val;
+
+    x86_jmprel_opcode_sel op_sel;
+} x86_targetval;
+
+void x86_ea_set_segment(effaddr *ea, unsigned char segment);
+effaddr *x86_ea_new_reg(unsigned long reg);
+effaddr *x86_ea_new_imm(immval *imm, unsigned char im_len);
+effaddr *x86_ea_new_expr(expr *e);
+
+effaddr *x86_bc_insn_get_ea(bytecode *bc);
+
+void x86_bc_insn_opersize_override(bytecode *bc, unsigned char opersize);
+void x86_bc_insn_addrsize_override(bytecode *bc, unsigned char addrsize);
+void x86_bc_insn_set_lockrep_prefix(bytecode *bc, unsigned char prefix);
+void x86_bc_insn_set_shift_flag(bytecode *bc);
+
+void x86_set_jmprel_opcode_sel(x86_jmprel_opcode_sel *old_sel,
+			       x86_jmprel_opcode_sel new_sel);
+
+/* Structure with *all* inputs passed to x86_bytecode_new_insn().
+ * IMPORTANT: ea_ptr and im_ptr cannot be reused or freed after calling the
+ * function (it doesn't make a copy).
+ */
+typedef struct x86_new_insn_data {
+    effaddr *ea;
+    immval *imm;
+    unsigned char opersize;
+    unsigned char op_len;
+    unsigned char op[3];
+    unsigned char spare;	/* bits to go in 'spare' field of ModRM */
+    unsigned char im_len;
+    unsigned char im_sign;
+} x86_new_insn_data;
+
+bytecode *x86_bc_new_insn(x86_new_insn_data *d);
+
+/* Structure with *all* inputs passed to x86_bytecode_new_jmprel().
+ * Pass 0 for the opcode_len if that version of the opcode doesn't exist.
+ */
+typedef struct x86_new_jmprel_data {
+    x86_targetval *target;
+    unsigned char short_op_len;
+    unsigned char short_op[3];
+    unsigned char near_op_len;
+    unsigned char near_op[3];
+    unsigned char addrsize;
+} x86_new_jmprel_data;
+
+bytecode *x86_bc_new_jmprel(x86_new_jmprel_data *d);
+
+extern unsigned char x86_mode_bits;
+
+#endif
diff --git a/src/arch/x86/x86bc.c b/src/arch/x86/x86bc.c
new file mode 100644
index 00000000..80837116
--- /dev/null
+++ b/src/arch/x86/x86bc.c
@@ -0,0 +1,512 @@
+/*
+ * x86 architecture description
+ *
+ *  Copyright (C) 2001  Peter Johnson
+ *
+ *  This file is part of YASM.
+ *
+ *  YASM is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  YASM is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+#include "util.h"
+RCSID("$IdPath$");
+
+#include "errwarn.h"
+#include "intnum.h"
+#include "expr.h"
+
+#include "bytecode.h"
+#include "arch.h"
+
+#include "x86-int.h"
+
+#include "bc-int.h"
+
+
+bytecode *
+x86_bc_new_insn(x86_new_insn_data *d)
+{
+    bytecode *bc;
+    x86_insn *insn;
+   
+    bc = bc_new_common(X86_BC_INSN, sizeof(x86_insn));
+    insn = bc_get_data(bc);
+
+    insn->ea = d->ea;
+    if (d->ea) {
+	x86_effaddr_data *ead = ea_get_data(d->ea);
+	ead->modrm &= 0xC7;	/* zero spare/reg bits */
+	ead->modrm |= (d->spare << 3) & 0x38;	/* plug in provided bits */
+    }
+
+    insn->imm = d->imm;
+    if (d->imm) {
+	insn->imm->f_len = d->im_len;
+	insn->imm->f_sign = d->im_sign;
+    }
+
+    insn->opcode[0] = d->op[0];
+    insn->opcode[1] = d->op[1];
+    insn->opcode[2] = d->op[2];
+    insn->opcode_len = d->op_len;
+
+    insn->addrsize = 0;
+    insn->opersize = d->opersize;
+    insn->lockrep_pre = 0;
+    insn->shift_op = 0;
+
+    insn->mode_bits = x86_mode_bits;
+
+    return bc;
+}
+
+bytecode *
+x86_bc_new_jmprel(x86_new_jmprel_data *d)
+{
+    bytecode *bc;
+    x86_jmprel *jmprel;
+
+    bc = bc_new_common(X86_BC_JMPREL, sizeof(x86_jmprel));
+    jmprel = bc_get_data(bc);
+
+    jmprel->target = d->target->val;
+    jmprel->op_sel = d->target->op_sel;
+
+    if ((d->target->op_sel == JR_SHORT_FORCED) && (d->near_op_len == 0))
+	Error(_("no SHORT form of that jump instruction exists"));
+    if ((d->target->op_sel == JR_NEAR_FORCED) && (d->short_op_len == 0))
+	Error(_("no NEAR form of that jump instruction exists"));
+
+    jmprel->shortop.opcode[0] = d->short_op[0];
+    jmprel->shortop.opcode[1] = d->short_op[1];
+    jmprel->shortop.opcode[2] = d->short_op[2];
+    jmprel->shortop.opcode_len = d->short_op_len;
+
+    jmprel->nearop.opcode[0] = d->near_op[0];
+    jmprel->nearop.opcode[1] = d->near_op[1];
+    jmprel->nearop.opcode[2] = d->near_op[2];
+    jmprel->nearop.opcode_len = d->near_op_len;
+
+    jmprel->addrsize = d->addrsize;
+    jmprel->opersize = 0;
+    jmprel->lockrep_pre = 0;
+
+    jmprel->mode_bits = x86_mode_bits;
+
+    return bc;
+}
+
+void
+x86_ea_set_segment(effaddr *ea, unsigned char segment)
+{
+    x86_effaddr_data *ead;
+
+    if (!ea)
+	return;
+
+    ead = ea_get_data(ea);
+
+    if (segment != 0 && ead->segment != 0)
+	Warning(_("multiple segment overrides, using leftmost"));
+
+    ead->segment = segment;
+}
+
+effaddr *
+x86_ea_new_reg(unsigned long reg)
+{
+    effaddr *ea = xmalloc(sizeof(effaddr)+sizeof(x86_effaddr_data));
+    x86_effaddr_data *ead = ea_get_data(ea);
+
+    ea->disp = (expr *)NULL;
+    ea->len = 0;
+    ea->nosplit = 0;
+    ead->segment = 0;
+    ead->modrm = 0xC0 | (reg & 0x07);	/* Mod=11, R/M=Reg, Reg=0 */
+    ead->valid_modrm = 1;
+    ead->need_modrm = 1;
+    ead->valid_sib = 0;
+    ead->need_sib = 0;
+
+    return ea;
+}
+
+effaddr *
+x86_ea_new_expr(expr *e)
+{
+    effaddr *ea = xmalloc(sizeof(effaddr)+sizeof(x86_effaddr_data));
+    x86_effaddr_data *ead = ea_get_data(ea);
+
+    ea->disp = e;
+    ea->len = 0;
+    ea->nosplit = 0;
+    ead->segment = 0;
+    ead->modrm = 0;
+    ead->valid_modrm = 0;
+    ead->need_modrm = 1;
+    ead->valid_sib = 0;
+    ead->need_sib = 0xff;   /* we won't know until we know more about expr and
+			       the BITS/address override setting */
+
+    return ea;
+}
+
+effaddr *
+x86_ea_new_imm(immval *imm, unsigned char im_len)
+{
+    effaddr *ea = xmalloc(sizeof(effaddr)+sizeof(x86_effaddr_data));
+    x86_effaddr_data *ead = ea_get_data(ea);
+
+    ea->disp = imm->val;
+    ea->len = im_len;
+    ea->nosplit = 0;
+    ead->segment = 0;
+    ead->modrm = 0;
+    ead->valid_modrm = 0;
+    ead->need_modrm = 0;
+    ead->valid_sib = 0;
+    ead->need_sib = 0;
+
+    return ea;
+}
+
+effaddr *
+x86_bc_insn_get_ea(bytecode *bc)
+{
+    x86_insn *insn = bc_get_data(bc);
+
+    if (!bc)
+	return NULL;
+
+    if (bc->type != X86_BC_INSN)
+	InternalError(_("Trying to get EA of non-instruction"));
+
+    return insn->ea;
+}
+
+void
+x86_bc_insn_opersize_override(bytecode *bc, unsigned char opersize)
+{
+    x86_insn *insn;
+    x86_jmprel *jmprel;
+
+    if (!bc)
+	return;
+
+    switch (bc->type) {
+	case X86_BC_INSN:
+	    insn = bc_get_data(bc);
+	    insn->opersize = opersize;
+	    break;
+	case X86_BC_JMPREL:
+	    jmprel = bc_get_data(bc);
+	    jmprel->opersize = opersize;
+	    break;
+	default:
+	    InternalError(_("OperSize override applied to non-instruction"));
+	    return;
+    }
+}
+
+void
+x86_bc_insn_addrsize_override(bytecode *bc, unsigned char addrsize)
+{
+    x86_insn *insn;
+    x86_jmprel *jmprel;
+
+    if (!bc)
+	return;
+
+    switch (bc->type) {
+	case X86_BC_INSN:
+	    insn = bc_get_data(bc);
+	    insn->addrsize = addrsize;
+	    break;
+	case X86_BC_JMPREL:
+	    jmprel = bc_get_data(bc);
+	    jmprel->addrsize = addrsize;
+	    break;
+	default:
+	    InternalError(_("AddrSize override applied to non-instruction"));
+	    return;
+    }
+}
+
+void
+x86_bc_insn_set_lockrep_prefix(bytecode *bc, unsigned char prefix)
+{
+    x86_insn *insn;
+    x86_jmprel *jmprel;
+    unsigned char *lockrep_pre = (unsigned char *)NULL;
+
+    if (!bc)
+	return;
+
+    switch (bc->type) {
+	case X86_BC_INSN:
+	    insn = bc_get_data(bc);
+	    lockrep_pre = &insn->lockrep_pre;
+	    break;
+	case X86_BC_JMPREL:
+	    jmprel = bc_get_data(bc);
+	    lockrep_pre = &jmprel->lockrep_pre;
+	    break;
+	default:
+	    InternalError(_("LockRep prefix applied to non-instruction"));
+	    return;
+    }
+
+    if (*lockrep_pre != 0)
+	Warning(_("multiple LOCK or REP prefixes, using leftmost"));
+
+    *lockrep_pre = prefix;
+}
+
+void
+x86_bc_insn_set_shift_flag(bytecode *bc)
+{
+    x86_insn *insn;
+
+    if (!bc)
+	return;
+
+    if (bc->type != X86_BC_INSN)
+	InternalError(_("Attempted to set shift flag on non-instruction"));
+
+    insn = bc_get_data(bc);
+
+    insn->shift_op = 1;
+}
+
+void
+x86_set_jmprel_opcode_sel(x86_jmprel_opcode_sel *old_sel,
+			  x86_jmprel_opcode_sel new_sel)
+{
+    if (!old_sel)
+	return;
+
+    if (new_sel != JR_NONE && ((*old_sel == JR_SHORT_FORCED) ||
+			       (*old_sel == JR_NEAR_FORCED)))
+	Warning(_("multiple SHORT or NEAR specifiers, using leftmost"));
+    *old_sel = new_sel;
+}
+
+void
+x86_bc_delete(bytecode *bc)
+{
+    x86_insn *insn;
+    x86_jmprel *jmprel;
+
+    switch ((x86_bytecode_type)bc->type) {
+	case X86_BC_INSN:
+	    insn = bc_get_data(bc);
+	    if (insn->ea) {
+		expr_delete(insn->ea->disp);
+		xfree(insn->ea);
+	    }
+	    if (insn->imm) {
+		expr_delete(insn->imm->val);
+		xfree(insn->imm);
+	    }
+	    break;
+	case X86_BC_JMPREL:
+	    jmprel = bc_get_data(bc);
+	    expr_delete(jmprel->target);
+	    break;
+    }
+}
+
+void
+x86_bc_print(const bytecode *bc)
+{
+    const x86_insn *insn;
+    const x86_jmprel *jmprel;
+    x86_effaddr_data *ead;
+
+    switch ((x86_bytecode_type)bc->type) {
+	case X86_BC_INSN:
+	    insn = bc_get_const_data(bc);
+	    printf("_Instruction_\n");
+	    printf("Effective Address:");
+	    if (!insn->ea)
+		printf(" (nil)\n");
+	    else {
+		printf("\n Disp=");
+		if (insn->ea->disp)
+		    expr_print(insn->ea->disp);
+		else
+		    printf("(nil)");
+		printf("\n");
+		ead = ea_get_data(insn->ea);
+		printf(" Len=%u SegmentOv=%02x NoSplit=%u\n",
+		       (unsigned int)insn->ea->len,
+		       (unsigned int)ead->segment,
+		       (unsigned int)insn->ea->nosplit);
+		printf(" ModRM=%03o ValidRM=%u NeedRM=%u\n",
+		       (unsigned int)ead->modrm,
+		       (unsigned int)ead->valid_modrm,
+		       (unsigned int)ead->need_modrm);
+		printf(" SIB=%03o ValidSIB=%u NeedSIB=%u\n",
+		       (unsigned int)ead->sib,
+		       (unsigned int)ead->valid_sib,
+		       (unsigned int)ead->need_sib);
+	    }
+	    printf("Immediate Value:");
+	    if (!insn->imm)
+		printf(" (nil)\n");
+	    else {
+		printf("\n Val=");
+		expr_print(insn->imm->val);
+		printf("\n");
+		printf(" Len=%u, IsNeg=%u\n",
+		       (unsigned int)insn->imm->len,
+		       (unsigned int)insn->imm->isneg);
+		printf(" FLen=%u, FSign=%u\n",
+		       (unsigned int)insn->imm->f_len,
+		       (unsigned int)insn->imm->f_sign);
+	    }
+	    printf("Opcode: %02x %02x %02x OpLen=%u\n",
+		   (unsigned int)insn->opcode[0],
+		   (unsigned int)insn->opcode[1],
+		   (unsigned int)insn->opcode[2],
+		   (unsigned int)insn->opcode_len);
+	    printf("AddrSize=%u OperSize=%u LockRepPre=%02x ShiftOp=%u\n",
+		   (unsigned int)insn->addrsize,
+		   (unsigned int)insn->opersize,
+		   (unsigned int)insn->lockrep_pre,
+		   (unsigned int)insn->shift_op);
+	    printf("BITS=%u\n", (unsigned int)insn->mode_bits);
+	    break;
+	case X86_BC_JMPREL:
+	    jmprel = bc_get_const_data(bc);
+	    printf("_Relative Jump_\n");
+	    printf("Target=");
+	    expr_print(jmprel->target);
+	    printf("\nShort Form:\n");
+	    if (!jmprel->shortop.opcode_len == 0)
+		printf(" None\n");
+	    else
+		printf(" Opcode: %02x %02x %02x OpLen=%u\n",
+		       (unsigned int)jmprel->shortop.opcode[0],
+		       (unsigned int)jmprel->shortop.opcode[1],
+		       (unsigned int)jmprel->shortop.opcode[2],
+		       (unsigned int)jmprel->shortop.opcode_len);
+	    if (!jmprel->nearop.opcode_len == 0)
+		printf(" None\n");
+	    else
+		printf(" Opcode: %02x %02x %02x OpLen=%u\n",
+		       (unsigned int)jmprel->nearop.opcode[0],
+		       (unsigned int)jmprel->nearop.opcode[1],
+		       (unsigned int)jmprel->nearop.opcode[2],
+		       (unsigned int)jmprel->nearop.opcode_len);
+	    printf("OpSel=");
+	    switch (jmprel->op_sel) {
+		case JR_NONE:
+		    printf("None");
+		    break;
+		case JR_SHORT:
+		    printf("Short");
+		    break;
+		case JR_NEAR:
+		    printf("Near");
+		    break;
+		case JR_SHORT_FORCED:
+		    printf("Forced Short");
+		    break;
+		case JR_NEAR_FORCED:
+		    printf("Forced Near");
+		    break;
+		default:
+		    printf("UNKNOWN!!");
+		    break;
+	    }
+	    printf("BITS=%u\nAddrSize=%u OperSize=%u LockRepPre=%02x\n",
+		   (unsigned int)jmprel->mode_bits,
+		   (unsigned int)jmprel->addrsize,
+		   (unsigned int)jmprel->opersize,
+		   (unsigned int)jmprel->lockrep_pre);
+	    break;
+    }
+}
+
+static void
+x86_bc_parser_finalize_insn(x86_insn *insn)
+{
+    effaddr *ea = insn->ea;
+    x86_effaddr_data *ead = ea_get_data(ea);
+    immval *imm = insn->imm;
+
+    if (ea) {
+	if ((ea->disp) && ((!ead->valid_sib && ead->need_sib) ||
+			   (!ead->valid_modrm && ead->need_modrm))) {
+	    /* First expand equ's */
+	    expr_expand_equ(ea->disp);
+
+	    /* Check validity of effective address and calc R/M bits of
+	     * Mod/RM byte and SIB byte.  We won't know the Mod field
+	     * of the Mod/RM byte until we know more about the
+	     * displacement.
+	     */
+	    if (!expr_checkea(&ea->disp, &insn->addrsize, insn->mode_bits,
+			      ea->nosplit, &ea->len, &ead->modrm,
+			      &ead->valid_modrm, &ead->need_modrm, &ead->sib,
+			      &ead->valid_sib, &ead->need_sib))
+		return;	    /* failed, don't bother checking rest of insn */
+	}
+    }
+
+    if (imm) {
+	const intnum *num;
+
+	if (imm->val) {
+	    expr_expand_equ(imm->val);
+	    expr_simplify(imm->val);
+	}
+	/* TODO: check imm f_len vs. len? */
+
+	/* Handle shift_op special-casing */
+	if (insn->shift_op && (num = expr_get_intnum(&imm->val))) {
+	    if (intnum_get_uint(num) == 1) {
+		/* Use ,1 form: first copy ,1 opcode. */
+		insn->opcode[0] = insn->opcode[1];
+		/* Delete ModRM, as it's no longer needed */
+		xfree(ea);
+		insn->ea = (effaddr *)NULL;
+		/* Delete Imm, as it's not needed */
+		expr_delete(imm->val);
+		xfree(imm);
+		insn->imm = (immval *)NULL;
+	    }
+	    insn->shift_op = 0;
+	}
+    }
+
+    
+}
+
+void
+x86_bc_parser_finalize(bytecode *bc)
+{
+    x86_insn *insn;
+
+    switch ((x86_bytecode_type)bc->type) {
+	case X86_BC_INSN:
+	    insn = bc_get_data(bc);
+	    x86_bc_parser_finalize_insn(insn);
+	    break;
+	default:
+	    break;
+    }
+}
+
diff --git a/src/bc-int.h b/src/bc-int.h
new file mode 100644
index 00000000..f992c465
--- /dev/null
+++ b/src/bc-int.h
@@ -0,0 +1,71 @@
+/* $IdPath$
+ * Bytecode internal structures header file
+ *
+ *  Copyright (C) 2001  Peter Johnson
+ *
+ *  This file is part of YASM.
+ *
+ *  YASM is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  YASM is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+#ifndef YASM_BC_INT_H
+#define YASM_BC_INT_H
+
+struct effaddr {
+    expr *disp;			/* address displacement */
+    unsigned char len;		/* length of disp (in bytes), 0 if unknown,
+				 * 0xff if unknown and required to be >0.
+				 */
+    unsigned char nosplit;	/* 1 if reg*2 should not be split into
+				   reg+reg. (0 if not) */
+
+    /* architecture-dependent data may be appended */
+};
+#define ea_get_data(x)		(void *)(((char *)x)+sizeof(effaddr))
+#define ea_get_const_data(x)	(const void *)(((const char *)x)+sizeof(effaddr))
+
+struct immval {
+    expr *val;
+
+    unsigned char len;		/* length of val (in bytes), 0 if unknown */
+    unsigned char isneg;	/* the value has been explicitly negated */
+
+    unsigned char f_len;	/* final imm length */
+    unsigned char f_sign;	/* 1 if final imm should be signed */
+};
+
+struct bytecode {
+    STAILQ_ENTRY(bytecode) link;
+
+    bytecode_type type;
+
+    expr *multiple;		/* number of times bytecode is repeated,
+				   NULL=1 */
+
+    unsigned long len;		/* total length of entire bytecode (including
+				   multiple copies), 0 if unknown */
+
+    /* where it came from */
+    const char *filename;
+    unsigned int lineno;
+
+    /* other assembler state info */
+    unsigned long offset;	/* 0 if unknown */
+
+    /* architecture-dependent data may be appended */
+};
+#define bc_get_data(x)		(void *)(((char *)x)+sizeof(bytecode))
+#define bc_get_const_data(x)	(const void *)(((const char *)x)+sizeof(bytecode))
+
+#endif
diff --git a/src/bytecode.c b/src/bytecode.c
index 407f01ec..6dae585d 100644
--- a/src/bytecode.c
+++ b/src/bytecode.c
@@ -29,40 +29,10 @@ RCSID("$IdPath$");
 
 #include "bytecode.h"
 
+#include "arch.h"
 
-struct effaddr {
-    expr *disp;			/* address displacement */
-    unsigned char len;		/* length of disp (in bytes), 0 if unknown,
-				 * 0xff if unknown and required to be >0.
-				 */
+#include "bc-int.h"
 
-    unsigned char segment;	/* segment override, 0 if none */
-
-    /* How the spare (register) bits in Mod/RM are handled:
-     * Even if valid_modrm=0, the spare bits are still valid (don't overwrite!)
-     * They're set in bytecode_new_insn().
-     */
-    unsigned char modrm;
-    unsigned char valid_modrm;	/* 1 if Mod/RM byte currently valid, 0 if not */
-    unsigned char need_modrm;	/* 1 if Mod/RM byte needed, 0 if not */
-
-    unsigned char sib;
-    unsigned char valid_sib;	/* 1 if SIB byte currently valid, 0 if not */
-    unsigned char need_sib;	/* 1 if SIB byte needed, 0 if not,
-				   0xff if unknown */
-    unsigned char nosplit;	/* 1 if reg*2 should not be split into
-				   reg+reg. (0 if not) */
-};
-
-struct immval {
-    expr *val;
-
-    unsigned char len;		/* length of val (in bytes), 0 if unknown */
-    unsigned char isneg;	/* the value has been explicitly negated */
-
-    unsigned char f_len;	/* final imm length */
-    unsigned char f_sign;	/* 1 if final imm should be signed */
-};
 
 struct dataval {
     STAILQ_ENTRY(dataval) link;
@@ -75,158 +45,25 @@ struct dataval {
     } data;
 };
 
-struct bytecode {
-    STAILQ_ENTRY(bytecode) link;
-
-    enum { BC_EMPTY, BC_INSN, BC_JMPREL, BC_DATA, BC_RESERVE } type;
-
-    /* This union has been somewhat tweaked to get it as small as possible
-     * on the 4-byte-aligned x86 architecture (without resorting to
-     * bitfields).  In particular, insn and jmprel are the largest structures
-     * in the union, and are also the same size (after padding).  jmprel
-     * can have another unsigned char added to the end without affecting
-     * its size.
-     *
-     * Don't worry about this too much, but keep it in mind when changing
-     * this structure.  We care about the size of bytecode in particular
-     * because it accounts for the majority of the memory usage in the
-     * assembler when assembling a large file.
-     */
-    union {
-	struct {
-	    effaddr *ea;	/* effective address */
-
-	    immval *imm;	/* immediate or relative value */
-
-	    unsigned char opcode[3];	/* opcode */
-	    unsigned char opcode_len;
-
-	    unsigned char addrsize;	/* 0 or =mode_bits => no override */
-	    unsigned char opersize;	/* 0 indicates no override */
-	    unsigned char lockrep_pre;	/* 0 indicates no prefix */
-
-	    /* HACK, but a space-saving one: shift opcodes have an immediate
-	     * form and a ,1 form (with no immediate).  In the parser, we
-	     * set this and opcode_len=1, but store the ,1 version in the
-	     * second byte of the opcode array.  We then choose between the
-	     * two versions once we know the actual value of imm (because we
-	     * don't know it in the parser module).
-	     *
-	     * A override to force the imm version should just leave this at
-	     * 0.  Then later code won't know the ,1 version even exists.
-	     * TODO: Figure out how this affects CPU flags processing.
-	     *
-	     * Call SetInsnShiftFlag() to set this flag to 1.
-	     */
-	    unsigned char shift_op;
-	} insn;
-	struct {
-	    expr *target;		/* target location */
-
-	    struct {
-		unsigned char opcode[3];
-		unsigned char opcode_len;   /* 0 = no opc for this version */
-	    } shortop, nearop;
-
-	    /* which opcode are we using? */
-	    /* The *FORCED forms are specified in the source as such */
-	    jmprel_opcode_sel op_sel;
-
-	    unsigned char addrsize;	/* 0 or =mode_bits => no override */
-	    unsigned char opersize;	/* 0 indicates no override */
-	    unsigned char lockrep_pre;	/* 0 indicates no prefix */
-	} jmprel;
-	struct {
-	    /* non-converted data (linked list) */
-	    datavalhead datahead;
-
-	    /* final (converted) size of each element (in bytes) */
-	    unsigned char size;
-	} data;
-	struct {
-	    expr *numitems;		/* number of items to reserve */
-	    unsigned char itemsize;	/* size of each item (in bytes) */
-	} reserve;
-    } data;
+typedef struct bytecode_data {
+    /* non-converted data (linked list) */
+    datavalhead datahead;
 
-    expr *multiple;		/* number of times bytecode is repeated,
-				   NULL=1 */
+    /* final (converted) size of each element (in bytes) */
+    unsigned char size;
+} bytecode_data;
 
-    unsigned long len;		/* total length of entire bytecode (including
-				   multiple copies), 0 if unknown */
-
-    /* where it came from */
-    const char *filename;
-    unsigned int lineno;
-
-    /* other assembler state info */
-    unsigned long offset;	/* 0 if unknown */
-    unsigned char mode_bits;
-};
+typedef struct bytecode_reserve {
+    expr *numitems;		/* number of items to reserve */
+    unsigned char itemsize;	/* size of each item (in bytes) */
+} bytecode_reserve;
 
 /* Static structures for when NULL is passed to conversion functions. */
 /*  for Convert*ToBytes() */
 unsigned char bytes_static[16];
 
-static bytecode *bytecode_new_common(void);
-
-effaddr *
-effaddr_new_reg(unsigned long reg)
-{
-    effaddr *ea = xmalloc(sizeof(effaddr));
-
-    ea->disp = (expr *)NULL;
-    ea->len = 0;
-    ea->segment = 0;
-    ea->modrm = 0xC0 | (reg & 0x07);	/* Mod=11, R/M=Reg, Reg=0 */
-    ea->valid_modrm = 1;
-    ea->need_modrm = 1;
-    ea->valid_sib = 0;
-    ea->need_sib = 0;
-    ea->nosplit = 0;
-
-    return ea;
-}
-
-effaddr *
-effaddr_new_expr(expr *expr_ptr)
-{
-    effaddr *ea = xmalloc(sizeof(effaddr));
-
-    ea->disp = expr_ptr;
-    ea->len = 0;
-    ea->segment = 0;
-    ea->modrm = 0;
-    ea->valid_modrm = 0;
-    ea->need_modrm = 1;
-    ea->valid_sib = 0;
-    ea->need_sib = 0xff;    /* we won't know until we know more about expr and
-			       the BITS/address override setting */
-    ea->nosplit = 0;
-
-    return ea;
-}
-
-effaddr *
-effaddr_new_imm(immval *im_ptr, unsigned char im_len)
-{
-    effaddr *ea = xmalloc(sizeof(effaddr));
-
-    ea->disp = im_ptr->val;
-    ea->len = im_len;
-    ea->segment = 0;
-    ea->modrm = 0;
-    ea->valid_modrm = 0;
-    ea->need_modrm = 0;
-    ea->valid_sib = 0;
-    ea->need_sib = 0;
-    ea->nosplit = 0;
-
-    return ea;
-}
-
 immval *
-immval_new_int(unsigned long int_val)
+imm_new_int(unsigned long int_val)
 {
     immval *im = xmalloc(sizeof(immval));
 
@@ -245,7 +82,7 @@ immval_new_int(unsigned long int_val)
 }
 
 immval *
-immval_new_expr(expr *expr_ptr)
+imm_new_expr(expr *expr_ptr)
 {
     immval *im = xmalloc(sizeof(immval));
 
@@ -257,19 +94,7 @@ immval_new_expr(expr *expr_ptr)
 }
 
 void
-SetEASegment(effaddr *ptr, unsigned char segment)
-{
-    if (!ptr)
-	return;
-
-    if (segment != 0 && ptr->segment != 0)
-	Warning(_("multiple segment overrides, using leftmost"));
-
-    ptr->segment = segment;
-}
-
-void
-SetEALen(effaddr *ptr, unsigned char len)
+ea_set_len(effaddr *ptr, unsigned char len)
 {
     if (!ptr)
 	return;
@@ -282,7 +107,7 @@ SetEALen(effaddr *ptr, unsigned char len)
 }
 
 void
-SetEANosplit(effaddr *ptr, unsigned char nosplit)
+ea_set_nosplit(effaddr *ptr, unsigned char nosplit)
 {
     if (!ptr)
 	return;
@@ -290,108 +115,8 @@ SetEANosplit(effaddr *ptr, unsigned char nosplit)
     ptr->nosplit = nosplit;
 }
 
-effaddr *
-GetInsnEA(bytecode *bc)
-{
-    if (!bc)
-	return NULL;
-
-    if (bc->type != BC_INSN)
-	InternalError(_("Trying to get EA of non-instruction"));
-
-    return bc->data.insn.ea;
-}
-
 void
-SetInsnOperSizeOverride(bytecode *bc, unsigned char opersize)
-{
-    if (!bc)
-	return;
-
-    switch (bc->type) {
-	case BC_INSN:
-	    bc->data.insn.opersize = opersize;
-	    break;
-	case BC_JMPREL:
-	    bc->data.jmprel.opersize = opersize;
-	    break;
-	default:
-	    InternalError(_("OperSize override applied to non-instruction"));
-	    return;
-    }
-}
-
-void
-SetInsnAddrSizeOverride(bytecode *bc, unsigned char addrsize)
-{
-    if (!bc)
-	return;
-
-    switch (bc->type) {
-	case BC_INSN:
-	    bc->data.insn.addrsize = addrsize;
-	    break;
-	case BC_JMPREL:
-	    bc->data.jmprel.addrsize = addrsize;
-	    break;
-	default:
-	    InternalError(_("AddrSize override applied to non-instruction"));
-	    return;
-    }
-}
-
-void
-SetInsnLockRepPrefix(bytecode *bc, unsigned char prefix)
-{
-    unsigned char *lockrep_pre = (unsigned char *)NULL;
-
-    if (!bc)
-	return;
-
-    switch (bc->type) {
-	case BC_INSN:
-	    lockrep_pre = &bc->data.insn.lockrep_pre;
-	    break;
-	case BC_JMPREL:
-	    lockrep_pre = &bc->data.jmprel.lockrep_pre;
-	    break;
-	default:
-	    InternalError(_("LockRep prefix applied to non-instruction"));
-	    return;
-    }
-
-    if (*lockrep_pre != 0)
-	Warning(_("multiple LOCK or REP prefixes, using leftmost"));
-
-    *lockrep_pre = prefix;
-}
-
-void
-SetInsnShiftFlag(bytecode *bc)
-{
-    if (!bc)
-	return;
-
-    if (bc->type != BC_INSN)
-	InternalError(_("Attempted to set shift flag on non-instruction"));
-
-    bc->data.insn.shift_op = 1;
-}
-
-void
-SetOpcodeSel(jmprel_opcode_sel *old_sel, jmprel_opcode_sel new_sel)
-{
-    if (!old_sel)
-	return;
-
-    if (new_sel != JR_NONE && ((*old_sel == JR_SHORT_FORCED) ||
-			       (*old_sel == JR_NEAR_FORCED)))
-	Warning(_("multiple SHORT or NEAR specifiers, using leftmost"));
-    *old_sel = new_sel;
-}
-
-void
-SetBCMultiple(bytecode *bc, expr *e)
+bc_set_multiple(bytecode *bc, expr *e)
 {
     if (bc->multiple)
 	bc->multiple = expr_new_tree(bc->multiple, EXPR_MUL, e);
@@ -399,10 +124,12 @@ SetBCMultiple(bytecode *bc, expr *e)
 	bc->multiple = e;
 }
 
-static bytecode *
-bytecode_new_common(void)
+bytecode *
+bc_new_common(bytecode_type type, size_t datasize)
 {
-    bytecode *bc = xmalloc(sizeof(bytecode));
+    bytecode *bc = xmalloc(sizeof(bytecode)+datasize);
+
+    bc->type = type;
 
     bc->multiple = (expr *)NULL;
     bc->len = 0;
@@ -411,146 +138,59 @@ bytecode_new_common(void)
     bc->lineno = line_number;
 
     bc->offset = 0;
-    bc->mode_bits = mode_bits;
 
     return bc;
 }
 
 bytecode *
-bytecode_new_insn(unsigned char  opersize,
-		  unsigned char  opcode_len,
-		  unsigned char  op0,
-		  unsigned char  op1,
-		  unsigned char  op2,
-		  effaddr       *ea_ptr,
-		  unsigned char  spare,
-		  immval        *im_ptr,
-		  unsigned char  im_len,
-		  unsigned char  im_sign)
+bc_new_data(datavalhead *datahead, unsigned long size)
 {
-    bytecode *bc = bytecode_new_common();
+    bytecode *bc = bc_new_common(BC_DATA, sizeof(bytecode_data));
+    bytecode_data *data = bc_get_data(bc);
 
-    bc->type = BC_INSN;
-
-    bc->data.insn.ea = ea_ptr;
-    if (ea_ptr) {
-	bc->data.insn.ea->modrm &= 0xC7;	/* zero spare/reg bits */
-	bc->data.insn.ea->modrm |= (spare << 3) & 0x38;	/* plug in provided bits */
-    }
-
-    bc->data.insn.imm = im_ptr;
-    if (im_ptr) {
-	bc->data.insn.imm->f_sign = im_sign;
-	bc->data.insn.imm->f_len = im_len;
-    }
-
-    bc->data.insn.opcode[0] = op0;
-    bc->data.insn.opcode[1] = op1;
-    bc->data.insn.opcode[2] = op2;
-    bc->data.insn.opcode_len = opcode_len;
-
-    bc->data.insn.addrsize = 0;
-    bc->data.insn.opersize = opersize;
-    bc->data.insn.lockrep_pre = 0;
-    bc->data.insn.shift_op = 0;
-
-    return bc;
-}
-
-bytecode *
-bytecode_new_jmprel(targetval     *target,
-		    unsigned char  short_opcode_len,
-		    unsigned char  short_op0,
-		    unsigned char  short_op1,
-		    unsigned char  short_op2,
-		    unsigned char  near_opcode_len,
-		    unsigned char  near_op0,
-		    unsigned char  near_op1,
-		    unsigned char  near_op2,
-		    unsigned char  addrsize)
-{
-    bytecode *bc = bytecode_new_common();
-
-    bc->type = BC_JMPREL;
-
-    bc->data.jmprel.target = target->val;
-    bc->data.jmprel.op_sel = target->op_sel;
-
-    if ((target->op_sel == JR_SHORT_FORCED) && (near_opcode_len == 0))
-	Error(_("no SHORT form of that jump instruction exists"));
-    if ((target->op_sel == JR_NEAR_FORCED) && (short_opcode_len == 0))
-	Error(_("no NEAR form of that jump instruction exists"));
-
-    bc->data.jmprel.shortop.opcode[0] = short_op0;
-    bc->data.jmprel.shortop.opcode[1] = short_op1;
-    bc->data.jmprel.shortop.opcode[2] = short_op2;
-    bc->data.jmprel.shortop.opcode_len = short_opcode_len;
-
-    bc->data.jmprel.nearop.opcode[0] = near_op0;
-    bc->data.jmprel.nearop.opcode[1] = near_op1;
-    bc->data.jmprel.nearop.opcode[2] = near_op2;
-    bc->data.jmprel.nearop.opcode_len = near_opcode_len;
-
-    bc->data.jmprel.addrsize = addrsize;
-    bc->data.jmprel.opersize = 0;
-    bc->data.jmprel.lockrep_pre = 0;
+    data->datahead = *datahead;
+    data->size = size;
 
     return bc;
 }
 
 bytecode *
-bytecode_new_data(datavalhead *datahead, unsigned long size)
+bc_new_reserve(expr *numitems, unsigned long itemsize)
 {
-    bytecode *bc = bytecode_new_common();
-
-    bc->type = BC_DATA;
+    bytecode *bc = bc_new_common(BC_RESERVE, sizeof(bytecode_reserve));
+    bytecode_reserve *reserve = bc_get_data(bc);
 
-    bc->data.data.datahead = *datahead;
-    bc->data.data.size = size;
-
-    return bc;
-}
-
-bytecode *
-bytecode_new_reserve(expr *numitems, unsigned long itemsize)
-{
-    bytecode *bc = bytecode_new_common();
-
-    bc->type = BC_RESERVE;
-
-    bc->data.reserve.numitems = numitems;
-    bc->data.reserve.itemsize = itemsize;
+    reserve->numitems = numitems;
+    reserve->itemsize = itemsize;
 
     return bc;
 }
 
 void
-bytecode_delete(bytecode *bc)
+bc_delete(bytecode *bc)
 {
+    bytecode_data *data;
+    bytecode_reserve *reserve;
+
     if (!bc)
 	return;
 
     switch (bc->type) {
 	case BC_EMPTY:
 	    break;
-	case BC_INSN:
-	    if (bc->data.insn.ea) {
-		expr_delete(bc->data.insn.ea->disp);
-		xfree(bc->data.insn.ea);
-	    }
-	    if (bc->data.insn.imm) {
-		expr_delete(bc->data.insn.imm->val);
-		xfree(bc->data.insn.imm);
-	    }
-	    break;
-	case BC_JMPREL:
-	    expr_delete(bc->data.jmprel.target);
-	    break;
 	case BC_DATA:
-	    datavals_delete(&bc->data.data.datahead);
+	    data = bc_get_data(bc);
+	    dvs_delete(&data->datahead);
 	    break;
 	case BC_RESERVE:
-	    expr_delete(bc->data.reserve.numitems);
+	    reserve = bc_get_data(bc);
+	    expr_delete(reserve->numitems);
+	    break;
+	default:
+	    if (bc->type < cur_arch->bc.type_max)
+		cur_arch->bc.bc_delete(bc);
+	    else
+		InternalError(_("Unknown bytecode type"));
 	    break;
     }
 
@@ -559,131 +199,43 @@ bytecode_delete(bytecode *bc)
 }
 
 int
-bytecode_get_offset(section *sect, bytecode *bc, unsigned long *ret_val)
+bc_get_offset(section *sect, bytecode *bc, unsigned long *ret_val)
 {
     return 0;	/* TODO */
 }
 
 void
-bytecode_print(const bytecode *bc)
+bc_print(const bytecode *bc)
 {
+    const bytecode_data *data;
+    const bytecode_reserve *reserve;
+
     switch (bc->type) {
 	case BC_EMPTY:
 	    printf("_Empty_\n");
 	    break;
-	case BC_INSN:
-	    printf("_Instruction_\n");
-	    printf("Effective Address:");
-	    if (!bc->data.insn.ea)
-		printf(" (nil)\n");
-	    else {
-		printf("\n Disp=");
-		if (bc->data.insn.ea->disp)
-		    expr_print(bc->data.insn.ea->disp);
-		else
-		    printf("(nil)");
-		printf("\n");
-		printf(" Len=%u SegmentOv=%02x NoSplit=%u\n",
-		       (unsigned int)bc->data.insn.ea->len,
-		       (unsigned int)bc->data.insn.ea->segment,
-		       (unsigned int)bc->data.insn.ea->nosplit);
-		printf(" ModRM=%03o ValidRM=%u NeedRM=%u\n",
-		       (unsigned int)bc->data.insn.ea->modrm,
-		       (unsigned int)bc->data.insn.ea->valid_modrm,
-		       (unsigned int)bc->data.insn.ea->need_modrm);
-		printf(" SIB=%03o ValidSIB=%u NeedSIB=%u\n",
-		       (unsigned int)bc->data.insn.ea->sib,
-		       (unsigned int)bc->data.insn.ea->valid_sib,
-		       (unsigned int)bc->data.insn.ea->need_sib);
-	    }
-	    printf("Immediate Value:");
-	    if (!bc->data.insn.imm)
-		printf(" (nil)\n");
-	    else {
-		printf("\n Val=");
-		expr_print(bc->data.insn.imm->val);
-		printf("\n");
-		printf(" Len=%u, IsNeg=%u\n",
-		       (unsigned int)bc->data.insn.imm->len,
-		       (unsigned int)bc->data.insn.imm->isneg);
-		printf(" FLen=%u, FSign=%u\n",
-		       (unsigned int)bc->data.insn.imm->f_len,
-		       (unsigned int)bc->data.insn.imm->f_sign);
-	    }
-	    printf("Opcode: %02x %02x %02x OpLen=%u\n",
-		   (unsigned int)bc->data.insn.opcode[0],
-		   (unsigned int)bc->data.insn.opcode[1],
-		   (unsigned int)bc->data.insn.opcode[2],
-		   (unsigned int)bc->data.insn.opcode_len);
-	    printf("AddrSize=%u OperSize=%u LockRepPre=%02x ShiftOp=%u\n",
-		   (unsigned int)bc->data.insn.addrsize,
-		   (unsigned int)bc->data.insn.opersize,
-		   (unsigned int)bc->data.insn.lockrep_pre,
-		   (unsigned int)bc->data.insn.shift_op);
-	    break;
-	case BC_JMPREL:
-	    printf("_Relative Jump_\n");
-	    printf("Target=");
-	    expr_print(bc->data.jmprel.target);
-	    printf("\nShort Form:\n");
-	    if (!bc->data.jmprel.shortop.opcode_len == 0)
-		printf(" None\n");
-	    else
-		printf(" Opcode: %02x %02x %02x OpLen=%u\n",
-		       (unsigned int)bc->data.jmprel.shortop.opcode[0],
-		       (unsigned int)bc->data.jmprel.shortop.opcode[1],
-		       (unsigned int)bc->data.jmprel.shortop.opcode[2],
-		       (unsigned int)bc->data.jmprel.shortop.opcode_len);
-	    if (!bc->data.jmprel.nearop.opcode_len == 0)
-		printf(" None\n");
-	    else
-		printf(" Opcode: %02x %02x %02x OpLen=%u\n",
-		       (unsigned int)bc->data.jmprel.nearop.opcode[0],
-		       (unsigned int)bc->data.jmprel.nearop.opcode[1],
-		       (unsigned int)bc->data.jmprel.nearop.opcode[2],
-		       (unsigned int)bc->data.jmprel.nearop.opcode_len);
-	    printf("OpSel=");
-	    switch (bc->data.jmprel.op_sel) {
-		case JR_NONE:
-		    printf("None");
-		    break;
-		case JR_SHORT:
-		    printf("Short");
-		    break;
-		case JR_NEAR:
-		    printf("Near");
-		    break;
-		case JR_SHORT_FORCED:
-		    printf("Forced Short");
-		    break;
-		case JR_NEAR_FORCED:
-		    printf("Forced Near");
-		    break;
-		default:
-		    printf("UNKNOWN!!");
-		    break;
-	    }
-	    printf("\nAddrSize=%u OperSize=%u LockRepPre=%02x\n",
-		   (unsigned int)bc->data.jmprel.addrsize,
-		   (unsigned int)bc->data.jmprel.opersize,
-		   (unsigned int)bc->data.jmprel.lockrep_pre);
-	    break;
 	case BC_DATA:
+	    data = bc_get_const_data(bc);
 	    printf("_Data_\n");
 	    printf("Final Element Size=%u\n",
-		   (unsigned int)bc->data.data.size);
+		   (unsigned int)data->size);
 	    printf("Elements:\n");
-	    datavals_print(&bc->data.data.datahead);
+	    dvs_print(&data->datahead);
 	    break;
 	case BC_RESERVE:
+	    reserve = bc_get_const_data(bc);
 	    printf("_Reserve_\n");
 	    printf("Num Items=");
-	    expr_print(bc->data.reserve.numitems);
+	    expr_print(reserve->numitems);
 	    printf("\nItem Size=%u\n",
-		   (unsigned int)bc->data.reserve.itemsize);
+		   (unsigned int)reserve->itemsize);
 	    break;
 	default:
-	    printf("_Unknown_\n");
+	    if (bc->type < cur_arch->bc.type_max)
+		cur_arch->bc.bc_print(bc);
+	    else
+		printf("_Unknown_\n");
+	    break;
     }
     printf("Multiple=");
     if (!bc->multiple)
@@ -694,95 +246,42 @@ bytecode_print(const bytecode *bc)
     printf("Length=%lu\n", bc->len);
     printf("Filename=\"%s\" Line Number=%u\n",
 	   bc->filename ? bc->filename : "<UNKNOWN>", bc->lineno);
-    printf("Offset=%lx BITS=%u\n", bc->offset, bc->mode_bits);
-}
-
-static void
-bytecode_parser_finalize_insn(bytecode *bc)
-{
-    effaddr *ea = bc->data.insn.ea;
-    immval *imm = bc->data.insn.imm;
-
-    if (ea) {
-	if ((ea->disp) && ((!ea->valid_sib && ea->need_sib) ||
-			   (!ea->valid_modrm && ea->need_modrm))) {
-	    /* First expand equ's */
-	    expr_expand_equ(ea->disp);
-
-	    /* Check validity of effective address and calc R/M bits of
-	     * Mod/RM byte and SIB byte.  We won't know the Mod field
-	     * of the Mod/RM byte until we know more about the
-	     * displacement.
-	     */
-	    if (!expr_checkea(&ea->disp, &bc->data.insn.addrsize,
-			      bc->mode_bits, ea->nosplit, &ea->len, &ea->modrm,
-			      &ea->valid_modrm, &ea->need_modrm, &ea->sib,
-			      &ea->valid_sib, &ea->need_sib))
-		return;	    /* failed, don't bother checking rest of insn */
-	}
-    }
-
-    if (imm) {
-	const intnum *num;
-
-	if (imm->val) {
-	    expr_expand_equ(imm->val);
-	    expr_simplify(imm->val);
-	}
-	/* TODO: check imm f_len vs. len? */
-
-	/* Handle shift_op special-casing */
-	if (bc->data.insn.shift_op && (num = expr_get_intnum(&imm->val))) {
-	    if (intnum_get_uint(num) == 1) {
-		/* Use ,1 form: first copy ,1 opcode. */
-		bc->data.insn.opcode[0] = bc->data.insn.opcode[1];
-		/* Delete ModRM, as it's no longer needed */
-		xfree(ea);
-		bc->data.insn.ea = (effaddr *)NULL;
-		/* Delete Imm, as it's not needed */
-		expr_delete(imm->val);
-		xfree(imm);
-		bc->data.insn.imm = (immval *)NULL;
-	    }
-	    bc->data.insn.shift_op = 0;
-	}
-    }
-
-    
+    printf("Offset=%lx\n", bc->offset);
 }
 
 void
-bytecode_parser_finalize(bytecode *bc)
+bc_parser_finalize(bytecode *bc)
 {
     switch (bc->type) {
 	case BC_EMPTY:
 	    /* FIXME: delete it (probably in bytecodes_ level, not here */
 	    InternalError(_("got empty bytecode in parser_finalize"));
 	    break;
-	case BC_INSN:
-	    bytecode_parser_finalize_insn(bc);
-	    break;
 	default:
+	    if (bc->type < cur_arch->bc.type_max)
+		cur_arch->bc.bc_parser_finalize(bc);
+	    else
+		InternalError(_("Unknown bytecode type"));
 	    break;
     }
 }
 
 void
-bytecodes_delete(bytecodehead *headp)
+bcs_delete(bytecodehead *headp)
 {
     bytecode *cur, *next;
 
     cur = STAILQ_FIRST(headp);
     while (cur) {
 	next = STAILQ_NEXT(cur, link);
-	bytecode_delete(cur);
+	bc_delete(cur);
 	cur = next;
     }
     STAILQ_INIT(headp);
 }
 
 bytecode *
-bytecodes_append(bytecodehead *headp, bytecode *bc)
+bcs_append(bytecodehead *headp, bytecode *bc)
 {
     if (bc) {
 	if (bc->type != BC_EMPTY) {
@@ -796,27 +295,27 @@ bytecodes_append(bytecodehead *headp, bytecode *bc)
 }
 
 void
-bytecodes_print(const bytecodehead *headp)
+bcs_print(const bytecodehead *headp)
 {
     bytecode *cur;
 
     STAILQ_FOREACH(cur, headp, link) {
 	printf("---Next Bytecode---\n");
-	bytecode_print(cur);
+	bc_print(cur);
     }
 }
 
 void
-bytecodes_parser_finalize(bytecodehead *headp)
+bcs_parser_finalize(bytecodehead *headp)
 {
     bytecode *cur;
 
     STAILQ_FOREACH(cur, headp, link)
-	bytecode_parser_finalize(cur);
+	bc_parser_finalize(cur);
 }
 
 dataval *
-dataval_new_expr(expr *expn)
+dv_new_expr(expr *expn)
 {
     dataval *retval = xmalloc(sizeof(dataval));
 
@@ -827,7 +326,7 @@ dataval_new_expr(expr *expn)
 }
 
 dataval *
-dataval_new_string(char *str_val)
+dv_new_string(char *str_val)
 {
     dataval *retval = xmalloc(sizeof(dataval));
 
@@ -838,7 +337,7 @@ dataval_new_string(char *str_val)
 }
 
 void
-datavals_delete(datavalhead *headp)
+dvs_delete(datavalhead *headp)
 {
     dataval *cur, *next;
 
@@ -854,7 +353,7 @@ datavals_delete(datavalhead *headp)
 }
 
 dataval *
-datavals_append(datavalhead *headp, dataval *dv)
+dvs_append(datavalhead *headp, dataval *dv)
 {
     if (dv) {
 	STAILQ_INSERT_TAIL(headp, dv, link);
@@ -864,7 +363,7 @@ datavals_append(datavalhead *headp, dataval *dv)
 }
 
 void
-datavals_print(const datavalhead *head)
+dvs_print(const datavalhead *head)
 {
     dataval *cur;
 
diff --git a/src/bytecode.h b/src/bytecode.h
index 3683bae9..38fa3113 100644
--- a/src/bytecode.h
+++ b/src/bytecode.h
@@ -27,87 +27,43 @@ typedef struct immval immval;
 typedef STAILQ_HEAD(datavalhead, dataval) datavalhead;
 typedef struct dataval dataval;
 
+/* Additional types may be architecture-defined starting at
+ * BYTECODE_TYPE_BASE.
+ */
 typedef enum {
-    JR_NONE,
-    JR_SHORT,
-    JR_NEAR,
-    JR_SHORT_FORCED,
-    JR_NEAR_FORCED
-} jmprel_opcode_sel;
-
-typedef struct targetval {
-    expr *val;
-
-    jmprel_opcode_sel op_sel;
-} targetval;
-
-effaddr *effaddr_new_reg(unsigned long reg);
-effaddr *effaddr_new_imm(immval *im_ptr, unsigned char im_len);
-effaddr *effaddr_new_expr(expr *expr_ptr);
+    BC_EMPTY = 0,
+    BC_DATA,
+    BC_RESERVE
+} bytecode_type;
+#define BYTECODE_TYPE_BASE  BC_RESERVE+1
 
-immval *immval_new_int(unsigned long int_val);
-immval *immval_new_expr(expr *expr_ptr);
+immval *imm_new_int(unsigned long int_val);
+immval *imm_new_expr(expr *e);
 
-void SetEASegment(effaddr *ptr, unsigned char segment);
-void SetEALen(effaddr *ptr, unsigned char len);
-void SetEANosplit(effaddr *ptr, unsigned char nosplit);
+void ea_set_len(effaddr *ea, unsigned char len);
+void ea_set_nosplit(effaddr *ea, unsigned char nosplit);
 
-effaddr *GetInsnEA(bytecode *bc);
+void bc_set_multiple(bytecode *bc, expr *e);
 
-void SetInsnOperSizeOverride(bytecode *bc, unsigned char opersize);
-void SetInsnAddrSizeOverride(bytecode *bc, unsigned char addrsize);
-void SetInsnLockRepPrefix(bytecode *bc, unsigned char prefix);
-void SetInsnShiftFlag(bytecode *bc);
+bytecode *bc_new_common(bytecode_type type, size_t datasize);
+bytecode *bc_new_data(datavalhead *datahead, unsigned long size);
+bytecode *bc_new_reserve(expr *numitems, unsigned long itemsize);
 
-void SetOpcodeSel(jmprel_opcode_sel *old_sel, jmprel_opcode_sel new_sel);
-
-void SetBCMultiple(bytecode *bc, expr *e);
-
-/* IMPORTANT: ea_ptr and im_ptr cannot be reused or freed after calling this
- * function (it doesn't make a copy).
- */
-bytecode *bytecode_new_insn(unsigned char  opersize,
-			    unsigned char  opcode_len,
-			    unsigned char  op0,
-			    unsigned char  op1,
-			    unsigned char  op2,
-			    effaddr       *ea_ptr,
-			    unsigned char  spare,
-			    immval        *im_ptr,
-			    unsigned char  im_len,
-			    unsigned char  im_sign);
-
-/* Pass 0 for the opcode_len if that version of the opcode doesn't exist. */
-bytecode *bytecode_new_jmprel(targetval     *target,
-			      unsigned char  short_opcode_len,
-			      unsigned char  short_op0,
-			      unsigned char  short_op1,
-			      unsigned char  short_op2,
-			      unsigned char  near_opcode_len,
-			      unsigned char  near_op0,
-			      unsigned char  near_op1,
-			      unsigned char  near_op2,
-			      unsigned char  addrsize);
-
-bytecode *bytecode_new_data(datavalhead *datahead, unsigned long size);
-
-bytecode *bytecode_new_reserve(expr *numitems, unsigned long itemsize);
-
-void bytecode_delete(bytecode *bc);
+void bc_delete(bytecode *bc);
 
 /* Gets the offset of the bytecode specified by bc if possible.
  * Return value is IF POSSIBLE, not the value.
  */
-int bytecode_get_offset(section *sect, bytecode *bc, unsigned long *ret_val);
+int bc_get_offset(section *sect, bytecode *bc, unsigned long *ret_val);
 
-void bytecode_print(const bytecode *bc);
+void bc_print(const bytecode *bc);
 
-void bytecode_parser_finalize(bytecode *bc);
+void bc_parser_finalize(bytecode *bc);
 
 /* void bytecodes_initialize(bytecodehead *headp); */
 #define	bytecodes_initialize(headp)	STAILQ_INIT(headp)
 
-void bytecodes_delete(bytecodehead *headp);
+void bcs_delete(bytecodehead *headp);
 
 /* Adds bc to the list of bytecodes headp.
  * NOTE: Does not make a copy of bc; so don't pass this function
@@ -115,20 +71,20 @@ void bytecodes_delete(bytecodehead *headp);
  * this function.  If bc was actually appended (it wasn't NULL or empty),
  * then returns bc, otherwise returns NULL.
  */
-bytecode *bytecodes_append(bytecodehead *headp, bytecode *bc);
+bytecode *bcs_append(bytecodehead *headp, bytecode *bc);
 
-void bytecodes_print(const bytecodehead *headp);
+void bcs_print(const bytecodehead *headp);
 
-void bytecodes_parser_finalize(bytecodehead *headp);
+void bcs_parser_finalize(bytecodehead *headp);
 
-dataval *dataval_new_expr(expr *expn);
-dataval *dataval_new_float(floatnum *flt);
-dataval *dataval_new_string(char *str_val);
+dataval *dv_new_expr(expr *expn);
+dataval *dv_new_float(floatnum *flt);
+dataval *dv_new_string(char *str_val);
 
-/* void datavals_initialize(datavalhead *headp); */
-#define	datavals_initialize(headp)	STAILQ_INIT(headp)
+/* void dvs_initialize(datavalhead *headp); */
+#define	dvs_initialize(headp)	STAILQ_INIT(headp)
 
-void datavals_delete(datavalhead *headp);
+void dvs_delete(datavalhead *headp);
 
 /* Adds dv to the list of datavals headp.
  * NOTE: Does not make a copy of dv; so don't pass this function
@@ -136,8 +92,8 @@ void datavals_delete(datavalhead *headp);
  * this function.  If dv was actually appended (it wasn't NULL), then
  * returns dv, otherwise returns NULL.
  */
-dataval *datavals_append(datavalhead *headp, dataval *dv);
+dataval *dvs_append(datavalhead *headp, dataval *dv);
 
-void datavals_print(const datavalhead *head);
+void dvs_print(const datavalhead *head);
 
 #endif
diff --git a/src/globals.c b/src/globals.c
index c21436a7..2239872f 100644
--- a/src/globals.c
+++ b/src/globals.c
@@ -29,7 +29,6 @@ RCSID("$IdPath$");
 
 const char *in_filename = (const char *)NULL;
 unsigned int line_number = 1;
-unsigned char mode_bits = 0;
 unsigned int asm_options = 0;
 
 static ternary_tree filename_table = (ternary_tree)NULL;
diff --git a/src/globals.h b/src/globals.h
index 23376e13..d0457793 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -24,7 +24,6 @@
 
 extern const char *in_filename;
 extern unsigned int line_number;
-extern unsigned char mode_bits;
 extern unsigned int asm_options;
 
 void switch_filename(const char *filename);
diff --git a/src/linemgr.c b/src/linemgr.c
index c21436a7..2239872f 100644
--- a/src/linemgr.c
+++ b/src/linemgr.c
@@ -29,7 +29,6 @@ RCSID("$IdPath$");
 
 const char *in_filename = (const char *)NULL;
 unsigned int line_number = 1;
-unsigned char mode_bits = 0;
 unsigned int asm_options = 0;
 
 static ternary_tree filename_table = (ternary_tree)NULL;
diff --git a/src/linemgr.h b/src/linemgr.h
index 23376e13..d0457793 100644
--- a/src/linemgr.h
+++ b/src/linemgr.h
@@ -24,7 +24,6 @@
 
 extern const char *in_filename;
 extern unsigned int line_number;
-extern unsigned char mode_bits;
 extern unsigned int asm_options;
 
 void switch_filename(const char *filename);
diff --git a/src/main.c b/src/main.c
index 0b4d711f..de7a27b9 100644
--- a/src/main.c
+++ b/src/main.c
@@ -41,6 +41,8 @@ RCSID("$IdPath$");
 #include "preproc.h"
 #include "parser.h"
 
+#include "arch.h"
+
 
 #ifndef countof
 #define countof(x,y)	(sizeof(x)/sizeof(y))
@@ -110,8 +112,11 @@ main(int argc, char *argv[])
 	switch_filename("<STDIN>");
     }
 
+    /* Set x86 as the architecture */
+    cur_arch = &x86_arch;
+
     /* Get initial BITS setting from object format */
-    mode_bits = dbg_objfmt.default_mode_bits;
+    x86_mode_bits = dbg_objfmt.default_mode_bits;
 
     sections = nasm_parser.do_parse(&nasm_parser, &dbg_objfmt, in);
 
diff --git a/src/parsers/nasm/bison.y.in b/src/parsers/nasm/bison.y.in
index 54893a76..fa318fd3 100644
--- a/src/parsers/nasm/bison.y.in
+++ b/src/parsers/nasm/bison.y.in
@@ -40,6 +40,7 @@ RCSID("$IdPath$");
 #include "section.h"
 #include "objfmt.h"
 
+#include "arch.h"
 
 #define YYDEBUG 1
 
@@ -56,6 +57,9 @@ extern char *nasm_parser_locallabel_base;
 static bytecode *nasm_parser_prev_bc = (bytecode *)NULL;
 static bytecode *nasm_parser_temp_bc;
 
+/* additional data declarations (dynamically generated) */
+/* @DATADECLS@ */
+
 %}
 
 %union {
@@ -68,7 +72,7 @@ static bytecode *nasm_parser_temp_bc;
     effaddr *ea;
     expr *exp;
     immval *im_val;
-    targetval tgt_val;
+    x86_targetval tgt_val;
     datavalhead datahead;
     dataval *data;
     bytecode *bc;
@@ -126,7 +130,7 @@ static bytecode *nasm_parser_temp_bc;
 %%
 input: /* empty */
     | input line    {
-	nasm_parser_temp_bc = bytecodes_append(section_get_bytecodes(nasm_parser_cur_section),
+	nasm_parser_temp_bc = bcs_append(section_get_bytecodes(nasm_parser_cur_section),
 					       $2);
 	if (nasm_parser_temp_bc)
 	    nasm_parser_prev_bc = nasm_parser_temp_bc;
@@ -145,10 +149,10 @@ line: '\n'		{ $$ = (bytecode *)NULL; }
 ;
 
 lineexp: exp
-    | TIMES expr exp			{ $$ = $3; SetBCMultiple($$, $2); }
+    | TIMES expr exp			{ $$ = $3; bc_set_multiple($$, $2); }
     | label				{ $$ = (bytecode *)NULL; }
     | label exp				{ $$ = $2; }
-    | label TIMES expr exp		{ $$ = $4; SetBCMultiple($$, $3); }
+    | label TIMES expr exp		{ $$ = $4; bc_set_multiple($$, $3); }
     | label_id EQU expr			{
 	symrec_define_equ($1, $3);
 	xfree($1);
@@ -157,22 +161,16 @@ lineexp: exp
 ;
 
 exp: instr
-    | DECLARE_DATA datavals	    { $$ = bytecode_new_data(&$2, $1); }
-    | RESERVE_SPACE expr	    { $$ = bytecode_new_reserve($2, $1); }
+    | DECLARE_DATA datavals	    { $$ = bc_new_data(&$2, $1); }
+    | RESERVE_SPACE expr	    { $$ = bc_new_reserve($2, $1); }
 ;
 
-datavals: dataval	    {
-	datavals_initialize(&$$);
-	datavals_append(&$$, $1);
-    }
-    | datavals ',' dataval  {
-	datavals_append(&$1, $3);
-	$$ = $1;
-    }
+datavals: dataval	    { dvs_initialize(&$$); dvs_append(&$$, $1); }
+    | datavals ',' dataval  { dvs_append(&$1, $3); $$ = $1; }
 ;
 
-dataval: expr_no_string	{ $$ = dataval_new_expr($1); }
-    | STRING		{ $$ = dataval_new_string($1); }
+dataval: expr_no_string	{ $$ = dv_new_expr($1); }
+    | STRING		{ $$ = dv_new_string($1); }
     | error		{
 	Error(_("expression syntax error"));
 	$$ = (dataval *)NULL;
@@ -317,17 +315,20 @@ memexpr: INTNUM			{ $$ = expr_new_ident(ExprInt($1)); }
     | error			{ Error(_("invalid effective address")); }
 ;
 
-memaddr: memexpr	    { $$ = effaddr_new_expr($1); SetEASegment($$, 0); }
-    | REG_CS ':' memaddr    { $$ = $3; SetEASegment($$, 0x2E); }
-    | REG_SS ':' memaddr    { $$ = $3; SetEASegment($$, 0x36); }
-    | REG_DS ':' memaddr    { $$ = $3; SetEASegment($$, 0x3E); }
-    | REG_ES ':' memaddr    { $$ = $3; SetEASegment($$, 0x26); }
-    | REG_FS ':' memaddr    { $$ = $3; SetEASegment($$, 0x64); }
-    | REG_GS ':' memaddr    { $$ = $3; SetEASegment($$, 0x65); }
-    | BYTE memaddr	    { $$ = $2; SetEALen($$, 1); }
-    | WORD memaddr	    { $$ = $2; SetEALen($$, 2); }
-    | DWORD memaddr	    { $$ = $2; SetEALen($$, 4); }
-    | NOSPLIT memaddr	    { $$ = $2; SetEANosplit($$, 1); }
+memaddr: memexpr	    {
+	$$ = x86_ea_new_expr($1);
+	x86_ea_set_segment($$, 0);
+    }
+    | REG_CS ':' memaddr    { $$ = $3; x86_ea_set_segment($$, 0x2E); }
+    | REG_SS ':' memaddr    { $$ = $3; x86_ea_set_segment($$, 0x36); }
+    | REG_DS ':' memaddr    { $$ = $3; x86_ea_set_segment($$, 0x3E); }
+    | REG_ES ':' memaddr    { $$ = $3; x86_ea_set_segment($$, 0x26); }
+    | REG_FS ':' memaddr    { $$ = $3; x86_ea_set_segment($$, 0x64); }
+    | REG_GS ':' memaddr    { $$ = $3; x86_ea_set_segment($$, 0x65); }
+    | BYTE memaddr	    { $$ = $2; ea_set_len($$, 1); }
+    | WORD memaddr	    { $$ = $2; ea_set_len($$, 2); }
+    | DWORD memaddr	    { $$ = $2; ea_set_len($$, 4); }
+    | NOSPLIT memaddr	    { $$ = $2; ea_set_nosplit($$, 1); }
 ;
 
 mem: '[' memaddr ']'	{ $$ = $2; }
@@ -378,43 +379,43 @@ mem1632: mem
 ;
 
 /* explicit register or memory */
-rm8x: reg8	{ $$ = effaddr_new_reg($1); }
+rm8x: reg8	{ $$ = x86_ea_new_reg($1); }
     | mem8x
 ;
-rm16x: reg16	{ $$ = effaddr_new_reg($1); }
+rm16x: reg16	{ $$ = x86_ea_new_reg($1); }
     | mem16x
 ;
-rm32x: reg32	{ $$ = effaddr_new_reg($1); }
+rm32x: reg32	{ $$ = x86_ea_new_reg($1); }
     | mem32x
 ;
 /* not needed:
-rm64x: MMXREG	{ $$ = effaddr_new_reg($1); }
+rm64x: MMXREG	{ $$ = x86_ea_new_reg($1); }
     | mem64x
 ;
-rm128x: XMMREG	{ $$ = effaddr_new_reg($1); }
+rm128x: XMMREG	{ $$ = x86_ea_new_reg($1); }
     | mem128x
 ;
 */
 
 /* implicit register or memory */
-rm8: reg8	{ $$ = effaddr_new_reg($1); }
+rm8: reg8	{ $$ = x86_ea_new_reg($1); }
     | mem8
 ;
-rm16: reg16	{ $$ = effaddr_new_reg($1); }
+rm16: reg16	{ $$ = x86_ea_new_reg($1); }
     | mem16
 ;
-rm32: reg32	{ $$ = effaddr_new_reg($1); }
+rm32: reg32	{ $$ = x86_ea_new_reg($1); }
     | mem32
 ;
-rm64: MMXREG	{ $$ = effaddr_new_reg($1); }
+rm64: MMXREG	{ $$ = x86_ea_new_reg($1); }
     | mem64
 ;
-rm128: XMMREG	{ $$ = effaddr_new_reg($1); }
+rm128: XMMREG	{ $$ = x86_ea_new_reg($1); }
     | mem128
 ;
 
 /* immediate values */
-imm: expr   { $$ = immval_new_expr($1); }
+imm: expr   { $$ = imm_new_expr($1); }
 ;
 
 /* explicit immediates */
@@ -437,9 +438,18 @@ imm32: imm
 ;
 
 /* jump targets */
-target: expr		{ $$.val = $1; SetOpcodeSel(&$$.op_sel, JR_NONE); }
-    | SHORT target	{ $$ = $2; SetOpcodeSel(&$$.op_sel, JR_SHORT_FORCED); }
-    | NEAR target	{ $$ = $2; SetOpcodeSel(&$$.op_sel, JR_NEAR_FORCED); }
+target: expr		{
+	$$.val = $1;
+	x86_set_jmprel_opcode_sel(&$$.op_sel, JR_NONE);
+    }
+    | SHORT target	{
+	$$ = $2;
+	x86_set_jmprel_opcode_sel(&$$.op_sel, JR_SHORT_FORCED);
+    }
+    | NEAR target	{
+	$$ = $2;
+	x86_set_jmprel_opcode_sel(&$$.op_sel, JR_NEAR_FORCED);
+    }
 ;
 
 /* expression trees */
@@ -493,18 +503,36 @@ explabel: ID		{ $$ = symrec_use($1); xfree($1); }
 ;
 
 instr: instrbase
-    | OPERSIZE instr	{ $$ = $2; SetInsnOperSizeOverride($$, $1); }
-    | ADDRSIZE instr	{ $$ = $2; SetInsnAddrSizeOverride($$, $1); }
-    | REG_CS instr	{ $$ = $2; SetEASegment(GetInsnEA($$), 0x2E); }
-    | REG_SS instr	{ $$ = $2; SetEASegment(GetInsnEA($$), 0x36); }
-    | REG_DS instr	{ $$ = $2; SetEASegment(GetInsnEA($$), 0x3E); }
-    | REG_ES instr	{ $$ = $2; SetEASegment(GetInsnEA($$), 0x26); }
-    | REG_FS instr	{ $$ = $2; SetEASegment(GetInsnEA($$), 0x64); }
-    | REG_GS instr	{ $$ = $2; SetEASegment(GetInsnEA($$), 0x65); }
-    | LOCK instr	{ $$ = $2; SetInsnLockRepPrefix($$, 0xF0); }
-    | REPNZ instr	{ $$ = $2; SetInsnLockRepPrefix($$, 0xF2); }
-    | REP instr		{ $$ = $2; SetInsnLockRepPrefix($$, 0xF3); }
-    | REPZ instr	{ $$ = $2; SetInsnLockRepPrefix($$, 0xF4); }
+    | OPERSIZE instr	{ $$ = $2; x86_bc_insn_opersize_override($$, $1); }
+    | ADDRSIZE instr	{ $$ = $2; x86_bc_insn_addrsize_override($$, $1); }
+    | REG_CS instr	{
+	$$ = $2;
+	x86_ea_set_segment(x86_bc_insn_get_ea($$), 0x2E);
+    }
+    | REG_SS instr	{
+	$$ = $2;
+	x86_ea_set_segment(x86_bc_insn_get_ea($$), 0x36);
+    }
+    | REG_DS instr	{
+	$$ = $2;
+	x86_ea_set_segment(x86_bc_insn_get_ea($$), 0x3E);
+    }
+    | REG_ES instr	{
+	$$ = $2;
+	x86_ea_set_segment(x86_bc_insn_get_ea($$), 0x26);
+    }
+    | REG_FS instr	{
+	$$ = $2;
+	x86_ea_set_segment(x86_bc_insn_get_ea($$), 0x64);
+    }
+    | REG_GS instr	{
+	$$ = $2;
+	x86_ea_set_segment(x86_bc_insn_get_ea($$), 0x65);
+    }
+    | LOCK instr	{ $$ = $2; x86_bc_insn_set_lockrep_prefix($$, 0xF0); }
+    | REPNZ instr	{ $$ = $2; x86_bc_insn_set_lockrep_prefix($$, 0xF2); }
+    | REP instr		{ $$ = $2; x86_bc_insn_set_lockrep_prefix($$, 0xF3); }
+    | REPZ instr	{ $$ = $2; x86_bc_insn_set_lockrep_prefix($$, 0xF4); }
 ;
 
 /* instruction grammars (dynamically generated) */
@@ -528,7 +556,7 @@ nasm_parser_directive(const char *name, const char *val)
 	if (*val == '\0' || *end != '\0' || (lval != 16 && lval != 32))
 	    Error(_("`%s' is not a valid argument to [BITS]"), val);
 	else
-	    mode_bits = (unsigned char)lval;
+	    x86_mode_bits = (unsigned char)lval;
     } else {
 	printf("Directive: Name=`%s' Value=`%s'\n", name, val);
     }
diff --git a/src/parsers/nasm/gen_instr.pl b/src/parsers/nasm/gen_instr.pl
index adaa58db..be391260 100755
--- a/src/parsers/nasm/gen_instr.pl
+++ b/src/parsers/nasm/gen_instr.pl
@@ -353,7 +353,8 @@ sub cond_action_if ( $ $ $ $ $ $ $ )
     my ($rule, $tokens, $count, $regarg, $val, $func, $a_eax) = splice (@_);
     return rule_header ($rule, $tokens, $count) . <<"EOF";
         if (\$$regarg == $val) {
-            \$\$ = $func(@$a_eax);
+            @$a_eax
+            \$\$ = $func;
         }
 EOF
 }
@@ -362,7 +363,8 @@ sub cond_action_elsif ( $ $ $ $ )
     my ($regarg, $val, $func, $a_eax) = splice (@_);
     return <<"EOF";
         else if (\$$regarg == $val) {
-            \$\$ = $func(@$a_eax);
+            @$a_eax
+            \$\$ = $func;
         }
 EOF
 }
@@ -371,7 +373,8 @@ sub cond_action_else ( $ $ )
     my ($func, $a_args) = splice (@_);
     return <<"EOF" . rule_footer;
         else {
-            \$\$ = $func (@$a_args);
+            @$a_args
+            \$\$ = $func;
         }
 EOF
 }
@@ -388,7 +391,8 @@ sub action ( @ $ )
 {
     my ($rule, $tokens, $func, $a_args, $count) = splice @_;
     return rule_header ($rule, $tokens, $count)
-	. "        \$\$ = $func (@$a_args);\n"
+	. "        @$a_args\n"
+	. "        \$\$ = $func;\n"
 	. rule_footer; 
 }
 
@@ -396,8 +400,9 @@ sub action_setshiftflag ( @ $ )
 {
     my ($rule, $tokens, $func, $a_args, $count) = splice @_;
     return rule_header ($rule, $tokens, $count)
-	. "        \$\$ = $func (@$a_args);\n"
-	. "        SetInsnShiftFlag(\$\$);\n"
+	. "        @$a_args\n"
+	. "        \$\$ = $func;\n"
+	. "        x86_bc_insn_set_shift_flag(\$\$);\n"
 	. rule_footer; 
 }
 
@@ -421,7 +426,12 @@ sub output_yacc ($@)
 
     while (<IN>)
     {
-	if (m{/[*]\s*[@]TOKENS[@]\s*[*]/})
+	if (m{/[*]\s*[@]DATADECLS[@]\s*[*]/})
+	{
+	    print GRAMMAR "static x86_new_insn_data idata;\n";
+	    print GRAMMAR "static x86_new_jmprel_data jrdata;\n";
+	}
+	elsif (m{/[*]\s*[@]TOKENS[@]\s*[*]/})
 	{
 	    my $len = length("%token <groupdata>");
 	    print GRAMMAR "%token <groupdata>";
@@ -500,69 +510,82 @@ sub output_yacc ($@)
 			    if $inst->[OPERANDS] ne 'nil';
 			$tokens =~ s/,/ ',' /g;
 			$tokens =~ s/:/ ':' /g;
-			my $func = "bytecode_new_jmprel";
+			my $datastruct = "x86_new_jmprel_data";
+			my $datastructname = "jrdata";
+			my $func = "x86_bc_new_jmprel(&$datastructname)";
 
 			# Create the argument list for bytecode_new
 			my @args;
 
 			# Target argument: HACK: Always assumed to be arg 1.
-			push @args, '&$2,';
+			push @args, 'target=&$2;';
 
 			# test for short opcode "nil"
 			if($inst->[SHORTOPCODE] =~ m/nil/)
 			{
-			    push @args, '0, 0, 0, 0,';
+			    push @args, 'short_op_len=0;';
+			    push @args, 'short_op[0]=0;';
+			    push @args, 'short_op[1]=0;';
+			    push @args, 'short_op[2]=0;';
 			}
 			else
 			{
-			    # number of bytes of short opcode
-			    push @args, (scalar(()=$inst->[SHORTOPCODE] =~ m/(,)/)+1) . ",";
-
 			    # opcode piece 1 (and 2 and 3 if attached)
-			    push @args, $inst->[SHORTOPCODE];
-			    $args[-1] =~ s/,/, /;
-			    $args[-1] =~ s/([0-9A-Fa-f]{2})/0x$1/g;
-			    # don't match $0.\d in the following rule.
-			    $args[-1] =~ s/\$(\d+)(?!\.)/"\$" . ($1*2)/eg;
-			    $args[-1] .= ',';
+			    my @opcodes = split ",", $inst->[SHORTOPCODE];
+			    # number of bytes of short opcode
+			    push @args, "short_op_len=".@opcodes.";";
+			    for (my $i=0; $i < @opcodes; ++$i)
+			    {
+				$opcodes[$i] =~ s/([0-9A-Fa-f]{2})/0x$1/g;
+				# don't match $0.\d in the following rule.
+				$opcodes[$i] =~ s/\$(\d+)(?!\.)/"\$".($1*2)/eg;
+				push @args, "short_op[$i]=$opcodes[$i];";
+			    }
 
 			    # opcode piece 2 (if not attached)
-			    push @args, "0," if $inst->[SHORTOPCODE] !~ m/,/o;
+			    push @args, "short_op[1]=0;" if @opcodes < 2;
 			    # opcode piece 3 (if not attached)
-			    push @args, "0," if $inst->[SHORTOPCODE] !~ m/,.*,/o;
+			    push @args, "short_op[2]=0;" if @opcodes < 3;
 			}
 
 			# test for near opcode "nil"
 			if($inst->[NEAROPCODE] =~ m/nil/)
 			{
-			    push @args, '0, 0, 0, 0,';
+			    push @args, 'near_op_len=0;';
+			    push @args, 'near_op[0]=0;';
+			    push @args, 'near_op[1]=0;';
+			    push @args, 'near_op[2]=0;';
 			}
 			else
 			{
-			    # number of bytes of near opcode
-			    push @args, (scalar(()=$inst->[NEAROPCODE] =~ m/(,)/)+1) . ",";
-
 			    # opcode piece 1 (and 2 and 3 if attached)
-			    push @args, $inst->[NEAROPCODE];
-			    $args[-1] =~ s/,/, /;
-			    $args[-1] =~ s/([0-9A-Fa-f]{2})/0x$1/g;
-			    # don't match $0.\d in the following rule.
-			    $args[-1] =~ s/\$(\d+)(?!\.)/"\$" . ($1*2)/eg;
-			    $args[-1] .= ',';
+			    my @opcodes = split ",", $inst->[NEAROPCODE];
+			    # number of bytes of near opcode
+			    push @args, "near_op_len=".@opcodes.";";
+			    for (my $i=0; $i < @opcodes; ++$i)
+			    {
+				$opcodes[$i] =~ s/([0-9A-Fa-f]{2})/0x$1/g;
+				# don't match $0.\d in the following rule.
+				$opcodes[$i] =~ s/\$(\d+)(?!\.)/"\$".($1*2)/eg;
+				push @args, "near_op[$i]=$opcodes[$i];";
+			    }
 
 			    # opcode piece 2 (if not attached)
-			    push @args, "0," if $inst->[NEAROPCODE] !~ m/,/o;
+			    push @args, "near_op[1]=0;" if @opcodes < 2;
 			    # opcode piece 3 (if not attached)
-			    push @args, "0," if $inst->[NEAROPCODE] !~ m/,.*,/o;
+			    push @args, "near_op[2]=0;" if @opcodes < 3;
 			}
 
 			# address size
-			push @args, "$inst->[ADSIZE]";
+			push @args, "addrsize=$inst->[ADSIZE];";
 			$args[-1] =~ s/nil/0/;
 
 			# now that we've constructed the arglist, subst $0.\d
 			s/\$0\.(\d+)/\$1\[$1\]/g foreach (@args);
 
+			# and add the data structure reference
+			s/^/$datastructname./g foreach (@args);
+
 			# generate the grammar
 			print GRAMMAR action ($rule, $tokens, $func, \@args, $count++);
 		    }
@@ -583,65 +606,79 @@ sub output_yacc ($@)
 			$tokens =~ s/:/ ':' /g;
 			# offset args
 			my $to = $tokens =~ m/\b(TO|WORD|DWORD)\b/ ? 1 : 0;
-			my $func = "bytecode_new_insn";
+			my $datastruct = "x86_new_insn_data";
+			my $datastructname = "idata";
+			my $func = "x86_bc_new_insn(&$datastructname)";
 
 			# Create the argument list for bytecode_new
 			my @args;
 
 			# operand size
-			push @args, "$inst->[OPSIZE],";
+			push @args, "opersize=$inst->[OPSIZE];";
 			$args[-1] =~ s/nil/0/;
 
-			# number of bytes of opcodes
-			push @args, (scalar(()=$inst->[OPCODE] =~ m/(,)/)+1) . ",";
 
 			# opcode piece 1 (and 2 and 3 if attached)
-			push @args, $inst->[OPCODE];
-			$args[-1] =~ s/,/, /;
-			$args[-1] =~ s/([0-9A-Fa-f]{2})/0x$1/g;
-			# don't match $0.\d in the following rule.
-			$args[-1] =~ s/\$(\d+)(?!\.)/"\$" . ($1*2+$to)/eg;
-			$args[-1] .= ',';
+			my @opcodes = split ",", $inst->[OPCODE];
+			# number of bytes of opcodes
+			push @args, "op_len=".@opcodes.";";
+			for (my $i=0; $i < @opcodes; ++$i)
+			{
+			    $opcodes[$i] =~ s/([0-9A-Fa-f]{2})/0x$1/g;
+			    # don't match $0.\d in the following rule.
+			    $opcodes[$i] =~ s/\$(\d+)(?!\.)/"\$".($1*2+$to)/eg;
+			    push @args, "op[$i]=$opcodes[$i];";
+			}
 
 			# opcode piece 2 (if not attached)
-			push @args, "0," if $inst->[OPCODE] !~ m/,/o;
+			push @args, "op[1]=0;" if @opcodes < 2;
 			# opcode piece 3 (if not attached)
-			push @args, "0," if $inst->[OPCODE] !~ m/,.*,/o;
+			push @args, "op[2]=0;" if @opcodes < 3;
 
 			# effective addresses
-			push @args, $inst->[EFFADDR];
-			$args[-1] =~ s/,/, /;
-			$args[-1] =~ s/^nil$/(effaddr *)NULL, 0/;
-			$args[-1] =~ s/nil/0/;
+			my $effaddr = $inst->[EFFADDR];
+			$effaddr =~ s/^nil/(effaddr *)NULL,0/;
+			$effaddr =~ s/nil/0/;
 			# don't let a $0.\d match slip into the following rules.
-			$args[-1] =~ s/\$(\d+)([ri])?(?!\.)/"\$".($1*2+$to).($2||'')/eg;
+			$effaddr =~ s/\$(\d+)([ri])?(?!\.)/"\$".($1*2+$to).($2||'')/eg;
 			#$args[-1] =~ s/(\$\d+[ri]?)(?!\.)/\&$1/; # Just the first!
-			$args[-1] =~ s/(\$\d+)r/effaddr_new_reg($1)/;
-			$args[-1] =~ s[(\$\d+)i,\s*(\d+)]
-			    ["effaddr_new_imm($1, ".($2/8)."), 0"]e;
-			$args[-1] .= ',';
+			$effaddr =~ s/(\$\d+)r/x86_ea_new_reg($1)/;
+			$effaddr =~ s[(\$\d+)i,\s*(\d+)]
+			    ["x86_ea_new_imm($1^ ".($2/8)."),0"]e;
 
-			die $args[-1] if $args[-1] =~ m/\d+[ri]/;
+			die $effaddr if $effaddr =~ m/\d+[ri]/;
+
+			my @effaddr_split = split ',', $effaddr;
+			$effaddr_split[0] =~ s/\^/,/;
+			push @args, "ea=$effaddr_split[0];";
+			push @args, "spare=$effaddr_split[1];";
 
 			# immediate sources
-			push @args, $inst->[IMM];
-			$args[-1] =~ s/,/, /;
-			$args[-1] =~ s/nil/(immval *)NULL, 0/;
+			my $imm = $inst->[IMM];
+			$imm =~ s/nil/(immval *)NULL,0/;
 			# don't match $0.\d in the following rules.
-			$args[-1] =~ s/\$(\d+)(?!\.)/"\$".($1*2+$to).($2||'')/eg;
-			$args[-1] =~ s[^([0-9A-Fa-f]+),]
-			    [immval_new_int(0x$1),];
-			$args[-1] =~ s[^\$0.(\d+),]
-			    [immval_new_int(\$1\[$1\]),];
+			$imm =~ s/\$(\d+)(?!\.)/"\$".($1*2+$to).($2||'')/eg;
+			$imm =~ s[^([0-9A-Fa-f]+),]
+			    [imm_new_int(0x$1),];
+			$imm =~ s[^\$0.(\d+),]
+			    [imm_new_int(\$1\[$1\]),];
 
 			# divide the second, and only the second, by 8 bits/byte
-			$args[-1] =~ s#(,\s*)(\d+)(s)?#$1 . ($2/8)#eg;
-			$args[-1] .= ($3||'') eq 's' ? ', 1' : ', 0';
+			$imm =~ s#(,\s*)(\d+)(s)?#$1 . ($2/8)#eg;
+			$imm .= ($3||'') eq 's' ? ',1' : ',0';
+
+			die $imm if $imm =~ m/\d+s/;
 
-			die $args[-1] if $args[-1] =~ m/\d+s/;
+			my @imm_split = split ",", $imm;
+			push @args, "imm=$imm_split[0];";
+			push @args, "im_len=$imm_split[1];";
+			push @args, "im_sign=$imm_split[2];";
 
 			# now that we've constructed the arglist, subst $0.\d
 			s/\$0\.(\d+)/\$1\[$1\]/g foreach (@args);
+
+			# and add the data structure reference
+			s/^/$datastructname./g foreach (@args);
 		    
 			# see if we match one of the cases to defer
 			if (($inst->[OPERANDS]||"") =~ m/,ONE/)
@@ -691,8 +728,9 @@ sub output_yacc ($@)
 			    # Now output imm version, with second opcode byte
 			    # set to ,1 opcode.  Also call SetInsnShiftFlag().
 			    $tokens =~ s/imm8x/imm/;
-			    die "no space for ONE?" if $args[3] !~ m/0,/;
-			    $args[3] = $ONE->[3]->[2];
+			    die "no space for ONE?" if $args[3] !~ m/0;/;
+			    my $oneval = $ONE->[3]->[2];
+			    $args[3] =~ s/0/$oneval/;
 			    print GRAMMAR action_setshiftflag ($rule, $tokens, $func, \@args, $count++);
 			}
 			elsif ($AL and ($inst->[OPERANDS]||"") =~ m/reg8,imm/)
diff --git a/src/parsers/nasm/nasm-bison.y b/src/parsers/nasm/nasm-bison.y
index 54893a76..fa318fd3 100644
--- a/src/parsers/nasm/nasm-bison.y
+++ b/src/parsers/nasm/nasm-bison.y
@@ -40,6 +40,7 @@ RCSID("$IdPath$");
 #include "section.h"
 #include "objfmt.h"
 
+#include "arch.h"
 
 #define YYDEBUG 1
 
@@ -56,6 +57,9 @@ extern char *nasm_parser_locallabel_base;
 static bytecode *nasm_parser_prev_bc = (bytecode *)NULL;
 static bytecode *nasm_parser_temp_bc;
 
+/* additional data declarations (dynamically generated) */
+/* @DATADECLS@ */
+
 %}
 
 %union {
@@ -68,7 +72,7 @@ static bytecode *nasm_parser_temp_bc;
     effaddr *ea;
     expr *exp;
     immval *im_val;
-    targetval tgt_val;
+    x86_targetval tgt_val;
     datavalhead datahead;
     dataval *data;
     bytecode *bc;
@@ -126,7 +130,7 @@ static bytecode *nasm_parser_temp_bc;
 %%
 input: /* empty */
     | input line    {
-	nasm_parser_temp_bc = bytecodes_append(section_get_bytecodes(nasm_parser_cur_section),
+	nasm_parser_temp_bc = bcs_append(section_get_bytecodes(nasm_parser_cur_section),
 					       $2);
 	if (nasm_parser_temp_bc)
 	    nasm_parser_prev_bc = nasm_parser_temp_bc;
@@ -145,10 +149,10 @@ line: '\n'		{ $$ = (bytecode *)NULL; }
 ;
 
 lineexp: exp
-    | TIMES expr exp			{ $$ = $3; SetBCMultiple($$, $2); }
+    | TIMES expr exp			{ $$ = $3; bc_set_multiple($$, $2); }
     | label				{ $$ = (bytecode *)NULL; }
     | label exp				{ $$ = $2; }
-    | label TIMES expr exp		{ $$ = $4; SetBCMultiple($$, $3); }
+    | label TIMES expr exp		{ $$ = $4; bc_set_multiple($$, $3); }
     | label_id EQU expr			{
 	symrec_define_equ($1, $3);
 	xfree($1);
@@ -157,22 +161,16 @@ lineexp: exp
 ;
 
 exp: instr
-    | DECLARE_DATA datavals	    { $$ = bytecode_new_data(&$2, $1); }
-    | RESERVE_SPACE expr	    { $$ = bytecode_new_reserve($2, $1); }
+    | DECLARE_DATA datavals	    { $$ = bc_new_data(&$2, $1); }
+    | RESERVE_SPACE expr	    { $$ = bc_new_reserve($2, $1); }
 ;
 
-datavals: dataval	    {
-	datavals_initialize(&$$);
-	datavals_append(&$$, $1);
-    }
-    | datavals ',' dataval  {
-	datavals_append(&$1, $3);
-	$$ = $1;
-    }
+datavals: dataval	    { dvs_initialize(&$$); dvs_append(&$$, $1); }
+    | datavals ',' dataval  { dvs_append(&$1, $3); $$ = $1; }
 ;
 
-dataval: expr_no_string	{ $$ = dataval_new_expr($1); }
-    | STRING		{ $$ = dataval_new_string($1); }
+dataval: expr_no_string	{ $$ = dv_new_expr($1); }
+    | STRING		{ $$ = dv_new_string($1); }
     | error		{
 	Error(_("expression syntax error"));
 	$$ = (dataval *)NULL;
@@ -317,17 +315,20 @@ memexpr: INTNUM			{ $$ = expr_new_ident(ExprInt($1)); }
     | error			{ Error(_("invalid effective address")); }
 ;
 
-memaddr: memexpr	    { $$ = effaddr_new_expr($1); SetEASegment($$, 0); }
-    | REG_CS ':' memaddr    { $$ = $3; SetEASegment($$, 0x2E); }
-    | REG_SS ':' memaddr    { $$ = $3; SetEASegment($$, 0x36); }
-    | REG_DS ':' memaddr    { $$ = $3; SetEASegment($$, 0x3E); }
-    | REG_ES ':' memaddr    { $$ = $3; SetEASegment($$, 0x26); }
-    | REG_FS ':' memaddr    { $$ = $3; SetEASegment($$, 0x64); }
-    | REG_GS ':' memaddr    { $$ = $3; SetEASegment($$, 0x65); }
-    | BYTE memaddr	    { $$ = $2; SetEALen($$, 1); }
-    | WORD memaddr	    { $$ = $2; SetEALen($$, 2); }
-    | DWORD memaddr	    { $$ = $2; SetEALen($$, 4); }
-    | NOSPLIT memaddr	    { $$ = $2; SetEANosplit($$, 1); }
+memaddr: memexpr	    {
+	$$ = x86_ea_new_expr($1);
+	x86_ea_set_segment($$, 0);
+    }
+    | REG_CS ':' memaddr    { $$ = $3; x86_ea_set_segment($$, 0x2E); }
+    | REG_SS ':' memaddr    { $$ = $3; x86_ea_set_segment($$, 0x36); }
+    | REG_DS ':' memaddr    { $$ = $3; x86_ea_set_segment($$, 0x3E); }
+    | REG_ES ':' memaddr    { $$ = $3; x86_ea_set_segment($$, 0x26); }
+    | REG_FS ':' memaddr    { $$ = $3; x86_ea_set_segment($$, 0x64); }
+    | REG_GS ':' memaddr    { $$ = $3; x86_ea_set_segment($$, 0x65); }
+    | BYTE memaddr	    { $$ = $2; ea_set_len($$, 1); }
+    | WORD memaddr	    { $$ = $2; ea_set_len($$, 2); }
+    | DWORD memaddr	    { $$ = $2; ea_set_len($$, 4); }
+    | NOSPLIT memaddr	    { $$ = $2; ea_set_nosplit($$, 1); }
 ;
 
 mem: '[' memaddr ']'	{ $$ = $2; }
@@ -378,43 +379,43 @@ mem1632: mem
 ;
 
 /* explicit register or memory */
-rm8x: reg8	{ $$ = effaddr_new_reg($1); }
+rm8x: reg8	{ $$ = x86_ea_new_reg($1); }
     | mem8x
 ;
-rm16x: reg16	{ $$ = effaddr_new_reg($1); }
+rm16x: reg16	{ $$ = x86_ea_new_reg($1); }
     | mem16x
 ;
-rm32x: reg32	{ $$ = effaddr_new_reg($1); }
+rm32x: reg32	{ $$ = x86_ea_new_reg($1); }
     | mem32x
 ;
 /* not needed:
-rm64x: MMXREG	{ $$ = effaddr_new_reg($1); }
+rm64x: MMXREG	{ $$ = x86_ea_new_reg($1); }
     | mem64x
 ;
-rm128x: XMMREG	{ $$ = effaddr_new_reg($1); }
+rm128x: XMMREG	{ $$ = x86_ea_new_reg($1); }
     | mem128x
 ;
 */
 
 /* implicit register or memory */
-rm8: reg8	{ $$ = effaddr_new_reg($1); }
+rm8: reg8	{ $$ = x86_ea_new_reg($1); }
     | mem8
 ;
-rm16: reg16	{ $$ = effaddr_new_reg($1); }
+rm16: reg16	{ $$ = x86_ea_new_reg($1); }
     | mem16
 ;
-rm32: reg32	{ $$ = effaddr_new_reg($1); }
+rm32: reg32	{ $$ = x86_ea_new_reg($1); }
     | mem32
 ;
-rm64: MMXREG	{ $$ = effaddr_new_reg($1); }
+rm64: MMXREG	{ $$ = x86_ea_new_reg($1); }
     | mem64
 ;
-rm128: XMMREG	{ $$ = effaddr_new_reg($1); }
+rm128: XMMREG	{ $$ = x86_ea_new_reg($1); }
     | mem128
 ;
 
 /* immediate values */
-imm: expr   { $$ = immval_new_expr($1); }
+imm: expr   { $$ = imm_new_expr($1); }
 ;
 
 /* explicit immediates */
@@ -437,9 +438,18 @@ imm32: imm
 ;
 
 /* jump targets */
-target: expr		{ $$.val = $1; SetOpcodeSel(&$$.op_sel, JR_NONE); }
-    | SHORT target	{ $$ = $2; SetOpcodeSel(&$$.op_sel, JR_SHORT_FORCED); }
-    | NEAR target	{ $$ = $2; SetOpcodeSel(&$$.op_sel, JR_NEAR_FORCED); }
+target: expr		{
+	$$.val = $1;
+	x86_set_jmprel_opcode_sel(&$$.op_sel, JR_NONE);
+    }
+    | SHORT target	{
+	$$ = $2;
+	x86_set_jmprel_opcode_sel(&$$.op_sel, JR_SHORT_FORCED);
+    }
+    | NEAR target	{
+	$$ = $2;
+	x86_set_jmprel_opcode_sel(&$$.op_sel, JR_NEAR_FORCED);
+    }
 ;
 
 /* expression trees */
@@ -493,18 +503,36 @@ explabel: ID		{ $$ = symrec_use($1); xfree($1); }
 ;
 
 instr: instrbase
-    | OPERSIZE instr	{ $$ = $2; SetInsnOperSizeOverride($$, $1); }
-    | ADDRSIZE instr	{ $$ = $2; SetInsnAddrSizeOverride($$, $1); }
-    | REG_CS instr	{ $$ = $2; SetEASegment(GetInsnEA($$), 0x2E); }
-    | REG_SS instr	{ $$ = $2; SetEASegment(GetInsnEA($$), 0x36); }
-    | REG_DS instr	{ $$ = $2; SetEASegment(GetInsnEA($$), 0x3E); }
-    | REG_ES instr	{ $$ = $2; SetEASegment(GetInsnEA($$), 0x26); }
-    | REG_FS instr	{ $$ = $2; SetEASegment(GetInsnEA($$), 0x64); }
-    | REG_GS instr	{ $$ = $2; SetEASegment(GetInsnEA($$), 0x65); }
-    | LOCK instr	{ $$ = $2; SetInsnLockRepPrefix($$, 0xF0); }
-    | REPNZ instr	{ $$ = $2; SetInsnLockRepPrefix($$, 0xF2); }
-    | REP instr		{ $$ = $2; SetInsnLockRepPrefix($$, 0xF3); }
-    | REPZ instr	{ $$ = $2; SetInsnLockRepPrefix($$, 0xF4); }
+    | OPERSIZE instr	{ $$ = $2; x86_bc_insn_opersize_override($$, $1); }
+    | ADDRSIZE instr	{ $$ = $2; x86_bc_insn_addrsize_override($$, $1); }
+    | REG_CS instr	{
+	$$ = $2;
+	x86_ea_set_segment(x86_bc_insn_get_ea($$), 0x2E);
+    }
+    | REG_SS instr	{
+	$$ = $2;
+	x86_ea_set_segment(x86_bc_insn_get_ea($$), 0x36);
+    }
+    | REG_DS instr	{
+	$$ = $2;
+	x86_ea_set_segment(x86_bc_insn_get_ea($$), 0x3E);
+    }
+    | REG_ES instr	{
+	$$ = $2;
+	x86_ea_set_segment(x86_bc_insn_get_ea($$), 0x26);
+    }
+    | REG_FS instr	{
+	$$ = $2;
+	x86_ea_set_segment(x86_bc_insn_get_ea($$), 0x64);
+    }
+    | REG_GS instr	{
+	$$ = $2;
+	x86_ea_set_segment(x86_bc_insn_get_ea($$), 0x65);
+    }
+    | LOCK instr	{ $$ = $2; x86_bc_insn_set_lockrep_prefix($$, 0xF0); }
+    | REPNZ instr	{ $$ = $2; x86_bc_insn_set_lockrep_prefix($$, 0xF2); }
+    | REP instr		{ $$ = $2; x86_bc_insn_set_lockrep_prefix($$, 0xF3); }
+    | REPZ instr	{ $$ = $2; x86_bc_insn_set_lockrep_prefix($$, 0xF4); }
 ;
 
 /* instruction grammars (dynamically generated) */
@@ -528,7 +556,7 @@ nasm_parser_directive(const char *name, const char *val)
 	if (*val == '\0' || *end != '\0' || (lval != 16 && lval != 32))
 	    Error(_("`%s' is not a valid argument to [BITS]"), val);
 	else
-	    mode_bits = (unsigned char)lval;
+	    x86_mode_bits = (unsigned char)lval;
     } else {
 	printf("Directive: Name=`%s' Value=`%s'\n", name, val);
     }
diff --git a/src/parsers/nasm/token.l.in b/src/parsers/nasm/token.l.in
index 8c1d6834..54002180 100644
--- a/src/parsers/nasm/token.l.in
+++ b/src/parsers/nasm/token.l.in
@@ -33,6 +33,8 @@ RCSID("$IdPath$");
 
 #include "bytecode.h"
 
+#include "arch.h"
+
 #include "bison.h"
 
 
diff --git a/src/section.c b/src/section.c
index 0ebccb7e..a95d185a 100644
--- a/src/section.c
+++ b/src/section.c
@@ -134,7 +134,7 @@ sections_parser_finalize(sectionhead *headp)
     section *cur;
     
     STAILQ_FOREACH(cur, headp, link)
-	bytecodes_parser_finalize(&cur->bc);
+	bcs_parser_finalize(&cur->bc);
 }
 
 bytecodehead *
@@ -156,7 +156,7 @@ section_delete(section *sect)
 	return;
 
     xfree(sect->name);
-    bytecodes_delete(&sect->bc);
+    bcs_delete(&sect->bc);
     xfree(sect);
 }
 
@@ -176,5 +176,5 @@ section_print(const section *sect)
     }
 
     printf(" Bytecodes:\n");
-    bytecodes_print(&sect->bc);
+    bcs_print(&sect->bc);
 }
diff --git a/src/symrec.c b/src/symrec.c
index eccb034f..020dee11 100644
--- a/src/symrec.c
+++ b/src/symrec.c
@@ -290,7 +290,7 @@ symrec_print(const symrec *sym)
 		printf("[First bytecode]\n");
 	    else {
 		printf("[Preceding bytecode]\n");
-		bytecode_print(sym->value.label.bc);
+		bc_print(sym->value.label.bc);
 	    }
 	    break;
     }
diff --git a/src/tests/Makefile.am b/src/tests/Makefile.am
index 9c7d9920..36e4bb1d 100644
--- a/src/tests/Makefile.am
+++ b/src/tests/Makefile.am
@@ -26,6 +26,7 @@ LDADD = \
 	$(top_builddir)/src/preprocs/raw/libpreproc.a		\
 	$(top_builddir)/src/optimizers/dbg/liboptimizer.a	\
 	$(top_builddir)/src/objfmts/dbg/libobjfmt.a		\
+	$(top_builddir)/src/arch/@ARCH@/libarch.a		\
 	$(top_builddir)/src/libyasm.a				\
 	$(INTLLIBS)
 
@@ -54,5 +55,5 @@ memexpr_test_SOURCES = \
 	memexpr_test.c
 
 INCLUDES= -I$(top_srcdir) -I$(top_srcdir)/src -I$(top_srcdir)/check \
-	-I$(top_builddir)/intl
+	-I$(top_srcdir)/src/arch/@ARCH@ -I$(top_builddir)/intl
 
diff --git a/src/tests/bytecode_test.c b/src/tests/bytecode_test.c
index 77eadc6a..f3411512 100644
--- a/src/tests/bytecode_test.c
+++ b/src/tests/bytecode_test.c
@@ -18,41 +18,41 @@
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
-#ifdef HAVE_CONFIG_H
-# include "config.h"
-#endif
-
-#ifdef STDC_HEADERS
-# include <stdlib.h>
-#endif
+#include "util.h"
 
 #include "check.h"
 
-#include "bytecode.c"
+#include "bytecode.h"
+#include "bc-int.h"
+#include "arch.h"
+#include "x86-int.h"
 
-START_TEST(test_effaddr_new_reg)
+START_TEST(test_x86_ea_new_reg)
 {
     effaddr *ea;
+    x86_effaddr_data *ead;
     int i;
 
     /* Test with NULL */
-    ea = effaddr_new_reg(1);
+    ea = x86_ea_new_reg(1);
     fail_unless(ea != NULL, "Should die if out of memory (not return NULL)");
 
     /* Test structure values function should set */
     fail_unless(ea->len == 0, "len should be 0");
-    fail_unless(ea->segment == 0, "Should be no segment override");
-    fail_unless(ea->valid_modrm == 1, "Mod/RM should be valid");
-    fail_unless(ea->need_modrm == 1, "Mod/RM should be needed");
-    fail_unless(ea->valid_sib == 0, "SIB should be invalid");
-    fail_unless(ea->need_sib == 0, "SIB should not be needed");
+    ead = ea_get_data(ea);
+    fail_unless(ead->segment == 0, "Should be no segment override");
+    fail_unless(ead->valid_modrm == 1, "Mod/RM should be valid");
+    fail_unless(ead->need_modrm == 1, "Mod/RM should be needed");
+    fail_unless(ead->valid_sib == 0, "SIB should be invalid");
+    fail_unless(ead->need_sib == 0, "SIB should not be needed");
 
     free(ea);
 
     /* Exhaustively test generated Mod/RM byte with register values */
     for(i=0; i<8; i++) {
-	ea = effaddr_new_reg(i);
-	fail_unless(ea->modrm == (0xC0 | (i & 0x07)),
+	ea = x86_ea_new_reg(i);
+	ead = ea_get_data(ea);
+	fail_unless(ead->modrm == (0xC0 | (i & 0x07)),
 		    "Invalid Mod/RM byte generated");
 	free(ea);
     }
@@ -66,7 +66,7 @@ bytecode_suite(void)
     TCase *tc_conversion = tcase_create("Conversion");
 
     suite_add_tcase(s, tc_conversion);
-    tcase_add_test(tc_conversion, test_effaddr_new_reg);
+    tcase_add_test(tc_conversion, test_x86_ea_new_reg);
 
     return s;
 }