From: Peter Johnson <peter@tortall.net>
Date: Wed, 3 Oct 2001 07:41:11 +0000 (-0000)
Subject: Fix mantissa rounding overflow issue: 0xff -> 0x100, and shift right -> 0x80 is
X-Git-Tag: v0.1.0~273
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=17a9427734fb8899d260cb12dd21690d13b4879a;p=yasm

Fix mantissa rounding overflow issue: 0xff -> 0x100, and shift right -> 0x80 is
not correct except when the 1 bit is explicit.

svn path=/trunk/yasm/; revision=257
---

diff --git a/libyasm/floatnum.c b/libyasm/floatnum.c
index a0488c98..6461f341 100644
--- a/libyasm/floatnum.c
+++ b/libyasm/floatnum.c
@@ -524,8 +524,9 @@ floatnum_get_common(unsigned char *ptr, const floatnum *flt, int byte_size,
 	BitVector_increment(output);
 
     if (BitVector_bit_test(output, mant_bits)) {
-	/* overflowed, so divide mantissa by 2 (shift right) */
-	BitVector_shift_right(output, 0);
+	/* overflowed, so zero mantissa (and set explicit bit if necessary) */
+	BitVector_Empty(output);
+	BitVector_Bit_Copy(output, mant_bits-1, !implicit1);
 	/* and up the exponent (checking for overflow) */
 	if (exponent+1 >= EXP_INF)
 	    overflow = 1;
diff --git a/src/floatnum.c b/src/floatnum.c
index a0488c98..6461f341 100644
--- a/src/floatnum.c
+++ b/src/floatnum.c
@@ -524,8 +524,9 @@ floatnum_get_common(unsigned char *ptr, const floatnum *flt, int byte_size,
 	BitVector_increment(output);
 
     if (BitVector_bit_test(output, mant_bits)) {
-	/* overflowed, so divide mantissa by 2 (shift right) */
-	BitVector_shift_right(output, 0);
+	/* overflowed, so zero mantissa (and set explicit bit if necessary) */
+	BitVector_Empty(output);
+	BitVector_Bit_Copy(output, mant_bits-1, !implicit1);
 	/* and up the exponent (checking for overflow) */
 	if (exponent+1 >= EXP_INF)
 	    overflow = 1;