From: Andy Polyakov <appro@openssl.org>
Date: Tue, 5 Jul 2011 09:21:03 +0000 (+0000)
Subject: x86_64-mont.pl: add squaring procedure and improve RSA sign performance
X-Git-Tag: OpenSSL-fips-2_0-rc1~267
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=6179f060776edf84d91fb231c5a0da6528284116;p=openssl

x86_64-mont.pl: add squaring procedure and improve RSA sign performance
by up to 38% (4096-bit benchmark on Core2).
---

diff --git a/crypto/bn/asm/x86_64-mont.pl b/crypto/bn/asm/x86_64-mont.pl
index 3b7a6f243f..71b0fe0dd2 100755
--- a/crypto/bn/asm/x86_64-mont.pl
+++ b/crypto/bn/asm/x86_64-mont.pl
@@ -15,6 +15,12 @@
 # respectful 50%. It remains to be seen if loop unrolling and
 # dedicated squaring routine can provide further improvement...
 
+# July 2011.
+#
+# Add dedicated squaring procedure. Performance improvement varies
+# from platform to platform, but in average it's ~5%/15%/25%/33%
+# for 512-/1024-/2048-/4096-bit RSA *sign* benchmarks respectively.
+
 $flavour = shift;
 $output  = shift;
 if ($flavour =~ /\./) { $output = $flavour; undef $flavour; }
@@ -37,7 +43,6 @@ $n0="%r8";	# const BN_ULONG *n0,
 $num="%r9";	# int num);
 $lo0="%r10";
 $hi0="%r11";
-$bp="%r12";	# reassign $bp
 $hi1="%r13";
 $i="%r14";
 $j="%r15";
@@ -51,6 +56,16 @@ $code=<<___;
 .type	bn_mul_mont,\@function,6
 .align	16
 bn_mul_mont:
+	cmp	$ap,$bp
+	jne	.Lmul_enter
+	test	\$1,${num}d
+	jnz	.Lmul_enter
+	cmp	\$4,${num}d
+	jb	.Lmul_enter
+	jmp	__bn_sqr_enter
+
+.align	16
+.Lmul_enter:
 	push	%rbx
 	push	%rbp
 	push	%r12
@@ -67,8 +82,10 @@ bn_mul_mont:
 
 	mov	%r11,8(%rsp,$num,8)	# tp[num+1]=%rsp
 .Lprologue:
-	mov	%rdx,$bp		# $bp reassigned, remember?
-
+	mov	$bp,%r12		# reassign $bp
+___
+		$bp="%r12";
+$code.=<<___;
 	mov	($n0),$n0		# pull n0[0] value
 
 	xor	$i,$i			# i=0
@@ -138,7 +155,8 @@ bn_mul_mont:
 	mov	%rdx,$hi1
 
 	lea	1($j),$j		# j++
-.align	4
+	jmp	.Linner
+.align	16
 .Linner:
 	mov	($ap,$j,8),%rax
 	mulq	$m0			# ap[j]*bp[i]
@@ -214,6 +232,420 @@ bn_mul_mont:
 .Lepilogue:
 	ret
 .size	bn_mul_mont,.-bn_mul_mont
+___
+{{{
+######################################################################
+# void bn_sqr_mont(
+my $rptr="%rdi";	# const BN_ULONG *rptr,
+my $aptr="%rsi";	# const BN_ULONG *aptr,
+my $bptr="%rdx";	# not used
+my $nptr="%rcx";	# const BN_ULONG *nptr,
+my $n0  ="%r8";		# const BN_ULONG *n0);
+my $num ="%r9";		# int num, has to be even and not less than 4
+
+my ($i,$j,$tptr)=("%rbp","%rcx",$rptr);
+my @A0=("%r10","%r11");
+my @A1=("%r12","%r13");
+my ($a0,$a1,$ai)=("%r14","%r15","%rbx");
+
+$code.=<<___;
+.type	bn_sqr_mont,\@function,5
+.align	16
+bn_sqr_mont:
+__bn_sqr_enter:
+	push	%rbx
+	push	%rbp
+	push	%r12
+	push	%r13
+	push	%r14
+	push	%r15
+
+	shl	\$3,${num}d		# convert $num to bytes
+	xor	%r10,%r10
+	mov	%rsp,%r11		# put aside %rsp
+	sub	$num,%r10		# -$num
+	mov	($n0),$n0		# *n0
+	lea	-72(%rsp,%r10,2),%rsp	# alloca(frame+2*$num)
+	and	\$-1024,%rsp		# minimize TLB usage
+	##############################################################
+	# Stack layout
+	#
+	# +0	saved $num, used in reduction section
+	# +8	&t[2*$num], used in reduction section
+	# +32	saved $rptr
+	# +40	saved $nptr
+	# +48	saved *n0
+	# +56	saved %rsp
+	# +64	t[2*$num]
+	#
+	mov	$rptr,32(%rsp)		# save $rptr
+	mov	$nptr,40(%rsp)
+	mov	$n0,  48(%rsp)
+	mov	%r11, 56(%rsp)		# save original %rsp
+.Lsqr_body:
+	##############################################################
+	# Squaring part:
+	#
+	# a) multiply-n-add everything but a[i]*a[i];
+	# b) shift result of a) by 1 to the left and accumulate
+	#    a[i]*a[i] products;
+	#
+	lea	16(%r10),$i		# $i=-($num-16)
+	lea	($aptr,$num),$aptr	# end of a[] buffer, ($aptr,$i)=&ap[2]
+
+	mov	$num,$j			# $j=$num
+	pxor	%xmm0,%xmm0
+	lea	64(%rsp),$tptr
+.Lbzero:				# clear t[$num]
+	movdqa	%xmm0,($tptr)
+	lea	16($tptr),$tptr
+	sub	\$16,$j
+	jnz	.Lbzero
+	jmp	.Lsqr_outer
+
+.align	16
+.Lsqr_outer:				# comments apply to $num==4 case
+	mov	-16($aptr,$i),$a0	# a[0]
+	lea	64(%rsp,$num,2),$tptr	# end of tp[] buffer, &tp[2*$num]
+	mov	-8($aptr,$i),%rax	# a[1]
+	lea	-16($tptr,$i),$tptr	# end of tp[] window, &tp[2*$num-"$i"]
+	mov	($aptr,$i),$ai		# a[2]
+	mov	%rax,$a1
+
+	mov	-8($tptr,$i),$A0[0]	# t[1]
+	xor	$A0[1],$A0[1]
+	mul	$a0			# a[1]*a[0]
+	add	%rax,$A0[0]		# a[1]*a[0]+t[1]
+	 mov	$ai,%rax		# a[2]
+	adc	%rdx,$A0[1]
+	mov	$A0[0],-8($tptr,$i)	# t[1]
+
+	xor	$A0[0],$A0[0]
+	add	($tptr,$i),$A0[1]	# a[2]*a[0]+t[2]
+	adc	\$0,$A0[0]
+	mul	$a0			# a[2]*a[0]
+	add	%rax,$A0[1]
+	 mov	$ai,%rax
+	adc	%rdx,$A0[0]
+	mov	$A0[1],($tptr,$i)	# t[2]
+
+	lea	($i),$j			# j=-16
+	xor	$A1[0],$A1[0]
+	jmp	.Lsqr_inner
+
+.align	16
+.Lsqr_inner:
+	 mov	8($aptr,$j),$ai		# a[3]
+	xor	$A1[1],$A1[1]
+	add	8($tptr,$j),$A1[0]
+	adc	\$0,$A1[1]
+	mul	$a1			# a[2]*a[1]
+	add	%rax,$A1[0]		# a[2]*a[1]+t[3]
+	 mov	$ai,%rax
+	adc	%rdx,$A1[1]
+
+	xor	$A0[1],$A0[1]
+	add	$A1[0],$A0[0]
+	adc	\$0,$A0[1]
+	mul	$a0			# a[3]*a[0]
+	add	%rax,$A0[0]		# a[3]*a[0]+a[2]*a[1]+t[3]
+	 mov	$ai,%rax
+	adc	%rdx,$A0[1]
+	mov	$A0[0],8($tptr,$j)	# t[3]
+
+	add	\$16,$j
+	jz	.Lsqr_inner_done
+
+	 mov	($aptr,$j),$ai		# a[4]
+	xor	$A1[0],$A1[0]
+	add	($tptr,$j),$A1[1]
+	adc	\$0,$A1[0]
+	mul	$a1			# a[3]*a[1]
+	add	%rax,$A1[1]		# a[3]*a[1]+t[4]
+	 mov	$ai,%rax
+	adc	%rdx,$A1[0]
+
+	xor	$A0[0],$A0[0]
+	add	$A1[1],$A0[1]
+	adc	\$0,$A0[0]
+	mul	$a0			# a[4]*a[0]
+	add	%rax,$A0[1]		# a[4]*a[0]+a[3]*a[1]+t[4]
+	 mov	$ai,%rax		# a[3]
+	adc	%rdx,$A0[0]
+	mov	$A0[1],($tptr,$j)	# t[4]
+	jmp	.Lsqr_inner
+
+.align	16
+.Lsqr_inner_done:
+	xor	$A1[0],$A1[0]
+	add	$A0[1],$A1[1]
+	adc	\$0,$A1[0]
+	mul	$a1			# a[3]*a[1]
+	add	%rax,$A1[1]
+	 mov	-16($aptr),%rax		# a[2]
+	adc	%rdx,$A1[0]
+
+	mov	$A1[1],($tptr)		# t[4]
+	mov	$A1[0],8($tptr)		# t[5]
+
+	add	\$16,$i
+	jnz	.Lsqr_outer
+
+	mul	$ai			# a[2]*a[3]
+___
+{
+my ($shift,$carry)=($a0,$a1);
+$code.=<<___;
+	 add	\$8,$i
+	 xor	$shift,$shift
+	 sub	$num,$i			# $i=8-$num
+	 xor	$carry,$carry
+
+	add	$A1[0],%rax		# t[5]
+	adc	\$0,%rdx
+	mov	%rax,8($tptr)		# t[5]
+	mov	%rdx,16($tptr)		# t[6]
+	mov	$carry,24($tptr)	# t[7]
+
+	 mov	-8($aptr,$i),%rax	# a[0]
+	lea	64(%rsp,$num,2),$tptr
+	 mov	-16($tptr,$i,2),$A0[0]	# t[0]
+	 mov	-8($tptr,$i,2),$A0[1]	# t[1]
+	jmp	.Lsqr_shift_n_add
+
+.align	16
+.Lsqr_shift_n_add:
+	lea	($shift,$A0[0],2),$A1[0]# t[2*i]<<1 | shift
+	shr	\$63,$A0[0]
+	lea	(,$A0[1],2),$A1[1]	# t[2*i+1]<<1 |
+	shr	\$63,$A0[1]
+	or	$A0[0],$A1[1]		# | t[2*i]>>63
+	 mov	0($tptr,$i,2),$A0[0]	# t[2*i+2]	# prefetch
+	mov	$A0[1],$shift		# shift=t[2*i+1]>>63
+	mul	%rax			# a[i]*a[i]
+	 mov	8($tptr,$i,2),$A0[1]	# t[2*i+2+1]	# prefetch
+	neg	$carry			# mov $carry,cf
+	adc	%rax,$A1[0]
+	 mov	0($aptr,$i),%rax	# a[i+1]	# prefetch
+	adc	%rdx,$A1[1]
+	mov	$A1[0],-16($tptr,$i,2)
+	sbb	$carry,$carry		# mov cf,$carry
+	mov	$A1[1],-8($tptr,$i,2)
+	add	\$8,$i
+	jnz	.Lsqr_shift_n_add
+
+	lea	($shift,$A0[0],2),$A1[0]# t[2*i]<<1|shift
+	shr	\$63,$A0[0]
+	lea	(,$A0[1],2),$A1[1]	# t[2*i+1]<<1 |
+	shr	\$63,$A0[1]
+	or	$A0[0],$A1[1]		# | t[2*i]>>63
+	mul	%rax			# a[i]*a[i]
+	neg	$carry			# mov $carry,cf
+	adc	%rax,$A1[0]
+	adc	%rdx,$A1[1]
+	mov	$A1[0],-16($tptr)
+	mov	$A1[1],-8($tptr)
+___
+}
+##############################################################
+# Montgomery reduction part, "word-by-word" algorithm.
+#
+{
+my ($topbit,$nptr)=("%rbp",$aptr);
+my ($m0,$m1)=($a0,$a1);
+my @Ni=("%rbx","%r9");
+$code.=<<___;
+	mov	40(%rsp),$nptr		# restore $nptr
+	xor	$j,$j
+	mov	$num,0(%rsp)		# save $num
+	sub	$num,$j			# $j=-$num
+	 mov	64(%rsp),$A0[0]		# t[0]		# modsched #
+	 mov	$n0,$m0			#		# modsched #
+	lea	64(%rsp,$num,2),%rax	# end of t[] buffer
+	lea	64(%rsp,$num),$tptr	# end of t[] window
+	mov	%rax,8(%rsp)		# save end of t[] buffer
+	lea	($nptr,$num),$nptr	# end of n[] buffer
+	xor	$topbit,$topbit		# $topbit=0
+
+	mov	0($nptr,$j),%rax	# n[0]		# modsched #
+	mov	8($nptr,$j),$Ni[1]	# n[1]		# modsched #
+	 imulq	$A0[0],$m0		# m0=t[0]*n0	# modsched #
+	 mov	%rax,$Ni[0]		#		# modsched #
+	jmp	.Lmont_outer
+
+.align	16
+.Lmont_outer:
+	xor	$A0[1],$A0[1]
+	mul	$m0			# n[0]*m0
+	add	%rax,$A0[0]		# n[0]*m0+t[0]
+	 mov	$Ni[1],%rax
+	adc	%rdx,$A0[1]
+	mov	$n0,$m1
+
+	xor	$A0[0],$A0[0]
+	add	8($tptr,$j),$A0[1]
+	adc	\$0,$A0[0]
+	mul	$m0			# n[1]*m0
+	add	%rax,$A0[1]		# n[1]*m0+t[1]
+	 mov	$Ni[0],%rax
+	adc	%rdx,$A0[0]
+
+	imulq	$A0[1],$m1
+	lea	16($j),$j
+	jmp	.Lmont_inner
+
+.align	16
+.Lmont_inner:
+	mov	($nptr,$j),$Ni[0]	# n[2]
+	xor	$A1[1],$A1[1]
+	add	$A0[1],$A1[0]
+	adc	\$0,$A1[1]
+	mul	$m1			# n[0]*m1
+	add	%rax,$A1[0]		# n[0]*m1+"t[1]"
+	 mov	$Ni[0],%rax
+	adc	%rdx,$A1[1]
+	mov	$A1[0],-8($tptr,$j)	# "t[1]"
+
+	xor	$A0[1],$A0[1]
+	add	($tptr,$j),$A0[0]
+	adc	\$0,$A0[1]
+	mul	$m0			# n[2]*m0
+	add	%rax,$A0[0]		# n[2]*m0+t[2]
+	 mov	$Ni[1],%rax
+	adc	%rdx,$A0[1]
+
+	mov	8($nptr,$j),$Ni[1]	# n[3]
+	xor	$A1[0],$A1[0]
+	add	$A0[0],$A1[1]
+	adc	\$0,$A1[0]
+	mul	$m1			# n[1]*m1
+	add	%rax,$A1[1]		# n[1]*m1+"t[2]"
+	 mov	$Ni[1],%rax
+	adc	%rdx,$A1[0]
+	mov	$A1[1],($tptr,$j)	# "t[2]"
+
+	xor	$A0[0],$A0[0]
+	add	8($tptr,$j),$A0[1]
+	lea	16($j),$j
+	adc	\$0,$A0[0]
+	mul	$m0			# n[3]*m0
+	add	%rax,$A0[1]		# n[3]*m0+t[3]
+	 mov	$Ni[0],%rax
+	adc	%rdx,$A0[0]
+	cmp	\$0,$j
+	jne	.Lmont_inner
+
+	 sub	0(%rsp),$j		# $j=-$num	# modsched #
+	 mov	$n0,$m0			#		# modsched #
+
+	xor	$A1[1],$A1[1]
+	add	$A0[1],$A1[0]
+	adc	\$0,$A1[1]
+	mul	$m1			# n[2]*m1
+	add	%rax,$A1[0]		# n[2]*m1+"t[3]"
+	mov	$Ni[1],%rax
+	adc	%rdx,$A1[1]
+	mov	$A1[0],-8($tptr)	# "t[3]"
+
+	xor	$A0[1],$A0[1]
+	add	($tptr),$A0[0]		# +t[4]
+	adc	\$0,$A0[1]
+	 mov	0($nptr,$j),$Ni[0]	# n[0]		# modsched #
+	add	$topbit,$A0[0]
+	adc	\$0,$A0[1]
+
+	 imulq	16($tptr,$j),$m0	# m0=t[0]*n0	# modsched #
+	xor	$A1[0],$A1[0]
+	 mov	8($nptr,$j),$Ni[1]	# n[1]		# modsched #
+	add	$A0[0],$A1[1]
+	 mov	16($tptr,$j),$A0[0]	# t[0]		# modsched #
+	adc	\$0,$A1[0]
+	mul	$m1			# n[3]*m1
+	add	%rax,$A1[1]		# n[3]*m1+"t[4]"
+	 mov	$Ni[0],%rax		#		# modsched #
+	adc	%rdx,$A1[0]
+	mov	$A1[1],($tptr)		# "t[4]"
+
+	xor	$topbit,$topbit
+	add	8($tptr),$A1[0]		# +t[5]
+	adc	$topbit,$topbit
+	add	$A0[1],$A1[0]
+	lea	16($tptr),$tptr		# "t[$num]>>128"
+	adc	\$0,$topbit
+	mov	$A1[0],-8($tptr)	# "t[5]"
+	cmp	8(%rsp),$tptr		# are we done?
+	jb	.Lmont_outer
+
+	mov	0(%rsp),$num		# restore $num
+	mov	$topbit,($tptr)		# save $topbit
+___
+}
+##############################################################
+# Post-condition, 2x unrolled copy from bn_mul_mont
+#
+{
+my ($tptr,$nptr)=("%rbx",$aptr);
+$code.=<<___;
+	lea	64(%rsp,$num),$tptr	# upper half of t[2*$num] holds result
+	shr	\$4,$num		# num/2
+	mov	32(%rsp),$rptr		# restore $rptr
+	mov	40(%rsp),$nptr		# restore $nptr
+	lea	-1($num),$j		# j=num/2-1
+
+	mov	($tptr),%rax		# tp[0]
+	xor	$i,$i			# i=0 and clear CF!
+	jmp	.Lsqr_sub
+.align	16
+.Lsqr_sub:
+	mov	8($tptr,$i,8),%rdx
+	sbb	0($nptr,$i,8),%rax
+	sbb	8($nptr,$i,8),%rdx
+	mov	%rax,0($rptr,$i,8)	# rp[i]=tp[i]-np[i]
+	mov	%rdx,8($rptr,$i,8)	# rp[i]=tp[i]-np[i]
+	mov	16($tptr,$i,8),%rax	# tp[i+1]
+	lea	2($i),$i		# i++
+	dec	$j			# doesn't affect CF!
+	jge	.Lsqr_sub
+
+	sbb	\$0,%rax		# handle upmost overflow bit
+	xor	$i,$i			# i=0
+	and	%rax,$tptr
+	not	%rax
+	mov	$rptr,$nptr
+	and	%rax,$nptr
+	lea	-1($num),$j
+	or	$nptr,$tptr		# tp=borrow?tp:rp
+
+	lea	64(%rsp,$num,8),$nptr
+	lea	($nptr,$num,8),$nptr
+	jmp	.Lsqr_copy
+.align	16
+.Lsqr_copy:				# copy or in-place refresh
+	movdqu	($tptr,$i),%xmm1
+	movdqa	%xmm0,64(%rsp,$i)	# zap lower half of temporary vector
+	movdqa	%xmm0,($nptr,$i)	# zap upper half of temporary vector
+	movdqu	%xmm1,($rptr,$i)
+	lea	16($i),$i
+	dec	$j
+	jge	.Lsqr_copy
+___
+}
+$code.=<<___;
+	mov	56(%rsp),%rsi		# restore %rsp
+	mov	\$1,%rax
+	mov	0(%rsi),%r15
+	mov	8(%rsi),%r14
+	mov	16(%rsi),%r13
+	mov	24(%rsi),%r12
+	mov	32(%rsi),%rbp
+	mov	40(%rsi),%rbx
+	lea	48(%rsi),%rsp
+.Lsqr_epilogue:
+	ret
+.size	bn_sqr_mont,.-bn_sqr_mont
+___
+}}}
+$code.=<<___;
 .asciz	"Montgomery Multiplication for x86_64, CRYPTOGAMS by <appro\@openssl.org>"
 .align	16
 ___
@@ -228,9 +660,9 @@ $disp="%r9";
 
 $code.=<<___;
 .extern	__imp_RtlVirtualUnwind
-.type	se_handler,\@abi-omnipotent
+.type	mul_handler,\@abi-omnipotent
 .align	16
-se_handler:
+mul_handler:
 	push	%rsi
 	push	%rdi
 	push	%rbx
@@ -247,13 +679,13 @@ se_handler:
 
 	lea	.Lprologue(%rip),%r10
 	cmp	%r10,%rbx		# context->Rip<.Lprologue
-	jb	.Lin_prologue
+	jb	.Lcommon_seh_tail
 
 	mov	152($context),%rax	# pull context->Rsp
 
 	lea	.Lepilogue(%rip),%r10
 	cmp	%r10,%rbx		# context->Rip>=.Lepilogue
-	jae	.Lin_prologue
+	jae	.Lcommon_seh_tail
 
 	mov	192($context),%r10	# pull $num
 	mov	8(%rax,%r10,8),%rax	# pull saved stack pointer
@@ -272,7 +704,53 @@ se_handler:
 	mov	%r14,232($context)	# restore context->R14
 	mov	%r15,240($context)	# restore context->R15
 
-.Lin_prologue:
+	jmp	.Lcommon_seh_tail
+.size	mul_handler,.-mul_handler
+
+.type	sqr_handler,\@abi-omnipotent
+.align	16
+sqr_handler:
+	push	%rsi
+	push	%rdi
+	push	%rbx
+	push	%rbp
+	push	%r12
+	push	%r13
+	push	%r14
+	push	%r15
+	pushfq
+	sub	\$64,%rsp
+
+	mov	120($context),%rax	# pull context->Rax
+	mov	248($context),%rbx	# pull context->Rip
+
+	lea	.Lsqr_body(%rip),%r10
+	cmp	%r10,%rbx		# context->Rip<.Lsqr_body
+	jb	.Lcommon_seh_tail
+
+	mov	152($context),%rax	# pull context->Rsp
+
+	lea	.Lsqr_epilogue(%rip),%r10
+	cmp	%r10,%rbx		# context->Rip>=.Lsqr_epilogue
+	jae	.Lcommon_seh_tail
+
+	mov	56(%rax),%rax		# pull saved stack pointer
+	lea	48(%rax),%rax
+
+	mov	-8(%rax),%rbx
+	mov	-16(%rax),%rbp
+	mov	-24(%rax),%r12
+	mov	-32(%rax),%r13
+	mov	-40(%rax),%r14
+	mov	-48(%rax),%r15
+	mov	%rbx,144($context)	# restore context->Rbx
+	mov	%rbp,160($context)	# restore context->Rbp
+	mov	%r12,216($context)	# restore context->R12
+	mov	%r13,224($context)	# restore context->R13
+	mov	%r14,232($context)	# restore context->R14
+	mov	%r15,240($context)	# restore context->R15
+
+.Lcommon_seh_tail:
 	mov	8(%rax),%rdi
 	mov	16(%rax),%rsi
 	mov	%rax,152($context)	# restore context->Rsp
@@ -310,7 +788,7 @@ se_handler:
 	pop	%rdi
 	pop	%rsi
 	ret
-.size	se_handler,.-se_handler
+.size	sqr_handler,.-sqr_handler
 
 .section	.pdata
 .align	4
@@ -318,11 +796,18 @@ se_handler:
 	.rva	.LSEH_end_bn_mul_mont
 	.rva	.LSEH_info_bn_mul_mont
 
+	.rva	.LSEH_begin_bn_sqr_mont
+	.rva	.LSEH_end_bn_sqr_mont
+	.rva	.LSEH_info_bn_sqr_mont
+
 .section	.xdata
 .align	8
 .LSEH_info_bn_mul_mont:
 	.byte	9,0,0,0
-	.rva	se_handler
+	.rva	mul_handler
+.LSEH_info_bn_sqr_mont:
+	.byte	9,0,0,0
+	.rva	sqr_handler
 ___
 }