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boringssl/crypto/fipsmodule/bn/asm/x86-mont.pl
Adam Langley 5c38c05b26 Move bn/ into crypto/fipsmodule/ 
Change-Id: I68aa4a740ee1c7f2a308a6536f408929f15b694c
Reviewed-on: https://boringssl-review.googlesource.com/15647
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: Adam Langley <agl@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
2017-05-01 22:51:25 +00:00

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#!/usr/bin/env perl
# ====================================================================
# Written by Andy Polyakov <appro@fy.chalmers.se> for the OpenSSL
# project. The module is, however, dual licensed under OpenSSL and
# CRYPTOGAMS licenses depending on where you obtain it. For further
# details see http://www.openssl.org/~appro/cryptogams/.
# ====================================================================
# October 2005
#
# This is a "teaser" code, as it can be improved in several ways...
# First of all non-SSE2 path should be implemented (yes, for now it
# performs Montgomery multiplication/convolution only on SSE2-capable
# CPUs such as P4, others fall down to original code). Then inner loop
# can be unrolled and modulo-scheduled to improve ILP and possibly
# moved to 128-bit XMM register bank (though it would require input
# rearrangement and/or increase bus bandwidth utilization). Dedicated
# squaring procedure should give further performance improvement...
# Yet, for being draft, the code improves rsa512 *sign* benchmark by
# 110%(!), rsa1024 one - by 70% and rsa4096 - by 20%:-)
# December 2006
#
# Modulo-scheduling SSE2 loops results in further 15-20% improvement.
# Integer-only code [being equipped with dedicated squaring procedure]
# gives ~40% on rsa512 sign benchmark...
$0 =~ m/(.*[\/\\])[^\/\\]+$/; $dir=$1;
push(@INC,"${dir}","${dir}../../../perlasm");
require "x86asm.pl";
$output = pop;
open STDOUT,">$output";
&asm_init($ARGV[0],$0);
$sse2=0;
for (@ARGV) { $sse2=1 if (/-DOPENSSL_IA32_SSE2/); }
&external_label("OPENSSL_ia32cap_P") if ($sse2);
&function_begin("bn_mul_mont");
$i="edx";
$j="ecx";
$ap="esi"; $tp="esi"; # overlapping variables!!!
$rp="edi"; $bp="edi"; # overlapping variables!!!
$np="ebp";
$num="ebx";
$_num=&DWP(4*0,"esp"); # stack top layout
$_rp=&DWP(4*1,"esp");
$_ap=&DWP(4*2,"esp");
$_bp=&DWP(4*3,"esp");
$_np=&DWP(4*4,"esp");
$_n0=&DWP(4*5,"esp"); $_n0q=&QWP(4*5,"esp");
$_sp=&DWP(4*6,"esp");
$_bpend=&DWP(4*7,"esp");
$frame=32; # size of above frame rounded up to 16n
&xor ("eax","eax");
&mov ("edi",&wparam(5)); # int num
&cmp ("edi",4);
&jl (&label("just_leave"));
&lea ("esi",&wparam(0)); # put aside pointer to argument block
&lea ("edx",&wparam(1)); # load ap
&add ("edi",2); # extra two words on top of tp
&neg ("edi");
&lea ("ebp",&DWP(-$frame,"esp","edi",4)); # future alloca($frame+4*(num+2))
&neg ("edi");
# minimize cache contention by arraning 2K window between stack
# pointer and ap argument [np is also position sensitive vector,
# but it's assumed to be near ap, as it's allocated at ~same
# time].
&mov ("eax","ebp");
&sub ("eax","edx");
&and ("eax",2047);
&sub ("ebp","eax"); # this aligns sp and ap modulo 2048
&xor ("edx","ebp");
&and ("edx",2048);
&xor ("edx",2048);
&sub ("ebp","edx"); # this splits them apart modulo 4096
&and ("ebp",-64); # align to cache line
# An OS-agnostic version of __chkstk.
#
# Some OSes (Windows) insist on stack being "wired" to
# physical memory in strictly sequential manner, i.e. if stack
# allocation spans two pages, then reference to farmost one can
# be punishable by SEGV. But page walking can do good even on
# other OSes, because it guarantees that villain thread hits
# the guard page before it can make damage to innocent one...
&mov ("eax","esp");
&sub ("eax","ebp");
&and ("eax",-4096);
&mov ("edx","esp"); # saved stack pointer!
&lea ("esp",&DWP(0,"ebp","eax"));
&mov ("eax",&DWP(0,"esp"));
&cmp ("esp","ebp");
&ja (&label("page_walk"));
&jmp (&label("page_walk_done"));
&set_label("page_walk",16);
&lea ("esp",&DWP(-4096,"esp"));
&mov ("eax",&DWP(0,"esp"));
&cmp ("esp","ebp");
&ja (&label("page_walk"));
&set_label("page_walk_done");
################################# load argument block...
&mov ("eax",&DWP(0*4,"esi"));# BN_ULONG *rp
&mov ("ebx",&DWP(1*4,"esi"));# const BN_ULONG *ap
&mov ("ecx",&DWP(2*4,"esi"));# const BN_ULONG *bp
&mov ("ebp",&DWP(3*4,"esi"));# const BN_ULONG *np
&mov ("esi",&DWP(4*4,"esi"));# const BN_ULONG *n0
#&mov ("edi",&DWP(5*4,"esi"));# int num
&mov ("esi",&DWP(0,"esi")); # pull n0[0]
&mov ($_rp,"eax"); # ... save a copy of argument block
&mov ($_ap,"ebx");
&mov ($_bp,"ecx");
&mov ($_np,"ebp");
&mov ($_n0,"esi");
&lea ($num,&DWP(-3,"edi")); # num=num-1 to assist modulo-scheduling
#&mov ($_num,$num); # redundant as $num is not reused
&mov ($_sp,"edx"); # saved stack pointer!
if($sse2) {
$acc0="mm0"; # mmx register bank layout
$acc1="mm1";
$car0="mm2";
$car1="mm3";
$mul0="mm4";
$mul1="mm5";
$temp="mm6";
$mask="mm7";
&picmeup("eax","OPENSSL_ia32cap_P");
&bt (&DWP(0,"eax"),26);
&jnc (&label("non_sse2"));
&mov ("eax",-1);
&movd ($mask,"eax"); # mask 32 lower bits
&mov ($ap,$_ap); # load input pointers
&mov ($bp,$_bp);
&mov ($np,$_np);
&xor ($i,$i); # i=0
&xor ($j,$j); # j=0
&movd ($mul0,&DWP(0,$bp)); # bp[0]
&movd ($mul1,&DWP(0,$ap)); # ap[0]
&movd ($car1,&DWP(0,$np)); # np[0]
&pmuludq($mul1,$mul0); # ap[0]*bp[0]
&movq ($car0,$mul1);
&movq ($acc0,$mul1); # I wish movd worked for
&pand ($acc0,$mask); # inter-register transfers
&pmuludq($mul1,$_n0q); # *=n0
&pmuludq($car1,$mul1); # "t[0]"*np[0]*n0
&paddq ($car1,$acc0);
&movd ($acc1,&DWP(4,$np)); # np[1]
&movd ($acc0,&DWP(4,$ap)); # ap[1]
&psrlq ($car0,32);
&psrlq ($car1,32);
&inc ($j); # j++
&set_label("1st",16);
&pmuludq($acc0,$mul0); # ap[j]*bp[0]
&pmuludq($acc1,$mul1); # np[j]*m1
&paddq ($car0,$acc0); # +=c0
&paddq ($car1,$acc1); # +=c1
&movq ($acc0,$car0);
&pand ($acc0,$mask);
&movd ($acc1,&DWP(4,$np,$j,4)); # np[j+1]
&paddq ($car1,$acc0); # +=ap[j]*bp[0];
&movd ($acc0,&DWP(4,$ap,$j,4)); # ap[j+1]
&psrlq ($car0,32);
&movd (&DWP($frame-4,"esp",$j,4),$car1); # tp[j-1]=
&psrlq ($car1,32);
&lea ($j,&DWP(1,$j));
&cmp ($j,$num);
&jl (&label("1st"));
&pmuludq($acc0,$mul0); # ap[num-1]*bp[0]
&pmuludq($acc1,$mul1); # np[num-1]*m1
&paddq ($car0,$acc0); # +=c0
&paddq ($car1,$acc1); # +=c1
&movq ($acc0,$car0);
&pand ($acc0,$mask);
&paddq ($car1,$acc0); # +=ap[num-1]*bp[0];
&movd (&DWP($frame-4,"esp",$j,4),$car1); # tp[num-2]=
&psrlq ($car0,32);
&psrlq ($car1,32);
&paddq ($car1,$car0);
&movq (&QWP($frame,"esp",$num,4),$car1); # tp[num].tp[num-1]
&inc ($i); # i++
&set_label("outer");
&xor ($j,$j); # j=0
&movd ($mul0,&DWP(0,$bp,$i,4)); # bp[i]
&movd ($mul1,&DWP(0,$ap)); # ap[0]
&movd ($temp,&DWP($frame,"esp")); # tp[0]
&movd ($car1,&DWP(0,$np)); # np[0]
&pmuludq($mul1,$mul0); # ap[0]*bp[i]
&paddq ($mul1,$temp); # +=tp[0]
&movq ($acc0,$mul1);
&movq ($car0,$mul1);
&pand ($acc0,$mask);
&pmuludq($mul1,$_n0q); # *=n0
&pmuludq($car1,$mul1);
&paddq ($car1,$acc0);
&movd ($temp,&DWP($frame+4,"esp")); # tp[1]
&movd ($acc1,&DWP(4,$np)); # np[1]
&movd ($acc0,&DWP(4,$ap)); # ap[1]
&psrlq ($car0,32);
&psrlq ($car1,32);
&paddq ($car0,$temp); # +=tp[1]
&inc ($j); # j++
&dec ($num);
&set_label("inner");
&pmuludq($acc0,$mul0); # ap[j]*bp[i]
&pmuludq($acc1,$mul1); # np[j]*m1
&paddq ($car0,$acc0); # +=c0
&paddq ($car1,$acc1); # +=c1
&movq ($acc0,$car0);
&movd ($temp,&DWP($frame+4,"esp",$j,4));# tp[j+1]
&pand ($acc0,$mask);
&movd ($acc1,&DWP(4,$np,$j,4)); # np[j+1]
&paddq ($car1,$acc0); # +=ap[j]*bp[i]+tp[j]
&movd ($acc0,&DWP(4,$ap,$j,4)); # ap[j+1]
&psrlq ($car0,32);
&movd (&DWP($frame-4,"esp",$j,4),$car1);# tp[j-1]=
&psrlq ($car1,32);
&paddq ($car0,$temp); # +=tp[j+1]
&dec ($num);
&lea ($j,&DWP(1,$j)); # j++
&jnz (&label("inner"));
&mov ($num,$j);
&pmuludq($acc0,$mul0); # ap[num-1]*bp[i]
&pmuludq($acc1,$mul1); # np[num-1]*m1
&paddq ($car0,$acc0); # +=c0
&paddq ($car1,$acc1); # +=c1
&movq ($acc0,$car0);
&pand ($acc0,$mask);
&paddq ($car1,$acc0); # +=ap[num-1]*bp[i]+tp[num-1]
&movd (&DWP($frame-4,"esp",$j,4),$car1); # tp[num-2]=
&psrlq ($car0,32);
&psrlq ($car1,32);
&movd ($temp,&DWP($frame+4,"esp",$num,4)); # += tp[num]
&paddq ($car1,$car0);
&paddq ($car1,$temp);
&movq (&QWP($frame,"esp",$num,4),$car1); # tp[num].tp[num-1]
&lea ($i,&DWP(1,$i)); # i++
&cmp ($i,$num);
&jle (&label("outer"));
&emms (); # done with mmx bank
&jmp (&label("common_tail"));
&set_label("non_sse2",16);
}
if (0) {
&mov ("esp",$_sp);
&xor ("eax","eax"); # signal "not fast enough [yet]"
&jmp (&label("just_leave"));
# While the below code provides competitive performance for
# all key lengths on modern Intel cores, it's still more
# than 10% slower for 4096-bit key elsewhere:-( "Competitive"
# means compared to the original integer-only assembler.
# 512-bit RSA sign is better by ~40%, but that's about all
# one can say about all CPUs...
} else {
$inp="esi"; # integer path uses these registers differently
$word="edi";
$carry="ebp";
&mov ($inp,$_ap);
&lea ($carry,&DWP(1,$num));
&mov ($word,$_bp);
&xor ($j,$j); # j=0
&mov ("edx",$inp);
&and ($carry,1); # see if num is even
&sub ("edx",$word); # see if ap==bp
&lea ("eax",&DWP(4,$word,$num,4)); # &bp[num]
&or ($carry,"edx");
&mov ($word,&DWP(0,$word)); # bp[0]
&jz (&label("bn_sqr_mont"));
&mov ($_bpend,"eax");
&mov ("eax",&DWP(0,$inp));
&xor ("edx","edx");
&set_label("mull",16);
&mov ($carry,"edx");
&mul ($word); # ap[j]*bp[0]
&add ($carry,"eax");
&lea ($j,&DWP(1,$j));
&adc ("edx",0);
&mov ("eax",&DWP(0,$inp,$j,4)); # ap[j+1]
&cmp ($j,$num);
&mov (&DWP($frame-4,"esp",$j,4),$carry); # tp[j]=
&jl (&label("mull"));
&mov ($carry,"edx");
&mul ($word); # ap[num-1]*bp[0]
&mov ($word,$_n0);
&add ("eax",$carry);
&mov ($inp,$_np);
&adc ("edx",0);
&imul ($word,&DWP($frame,"esp")); # n0*tp[0]
&mov (&DWP($frame,"esp",$num,4),"eax"); # tp[num-1]=
&xor ($j,$j);
&mov (&DWP($frame+4,"esp",$num,4),"edx"); # tp[num]=
&mov (&DWP($frame+8,"esp",$num,4),$j); # tp[num+1]=
&mov ("eax",&DWP(0,$inp)); # np[0]
&mul ($word); # np[0]*m
&add ("eax",&DWP($frame,"esp")); # +=tp[0]
&mov ("eax",&DWP(4,$inp)); # np[1]
&adc ("edx",0);
&inc ($j);
&jmp (&label("2ndmadd"));
&set_label("1stmadd",16);
&mov ($carry,"edx");
&mul ($word); # ap[j]*bp[i]
&add ($carry,&DWP($frame,"esp",$j,4)); # +=tp[j]
&lea ($j,&DWP(1,$j));
&adc ("edx",0);
&add ($carry,"eax");
&mov ("eax",&DWP(0,$inp,$j,4)); # ap[j+1]
&adc ("edx",0);
&cmp ($j,$num);
&mov (&DWP($frame-4,"esp",$j,4),$carry); # tp[j]=
&jl (&label("1stmadd"));
&mov ($carry,"edx");
&mul ($word); # ap[num-1]*bp[i]
&add ("eax",&DWP($frame,"esp",$num,4)); # +=tp[num-1]
&mov ($word,$_n0);
&adc ("edx",0);
&mov ($inp,$_np);
&add ($carry,"eax");
&adc ("edx",0);
&imul ($word,&DWP($frame,"esp")); # n0*tp[0]
&xor ($j,$j);
&add ("edx",&DWP($frame+4,"esp",$num,4)); # carry+=tp[num]
&mov (&DWP($frame,"esp",$num,4),$carry); # tp[num-1]=
&adc ($j,0);
&mov ("eax",&DWP(0,$inp)); # np[0]
&mov (&DWP($frame+4,"esp",$num,4),"edx"); # tp[num]=
&mov (&DWP($frame+8,"esp",$num,4),$j); # tp[num+1]=
&mul ($word); # np[0]*m
&add ("eax",&DWP($frame,"esp")); # +=tp[0]
&mov ("eax",&DWP(4,$inp)); # np[1]
&adc ("edx",0);
&mov ($j,1);
&set_label("2ndmadd",16);
&mov ($carry,"edx");
&mul ($word); # np[j]*m
&add ($carry,&DWP($frame,"esp",$j,4)); # +=tp[j]
&lea ($j,&DWP(1,$j));
&adc ("edx",0);
&add ($carry,"eax");
&mov ("eax",&DWP(0,$inp,$j,4)); # np[j+1]
&adc ("edx",0);
&cmp ($j,$num);
&mov (&DWP($frame-8,"esp",$j,4),$carry); # tp[j-1]=
&jl (&label("2ndmadd"));
&mov ($carry,"edx");
&mul ($word); # np[j]*m
&add ($carry,&DWP($frame,"esp",$num,4)); # +=tp[num-1]
&adc ("edx",0);
&add ($carry,"eax");
&adc ("edx",0);
&mov (&DWP($frame-4,"esp",$num,4),$carry); # tp[num-2]=
&xor ("eax","eax");
&mov ($j,$_bp); # &bp[i]
&add ("edx",&DWP($frame+4,"esp",$num,4)); # carry+=tp[num]
&adc ("eax",&DWP($frame+8,"esp",$num,4)); # +=tp[num+1]
&lea ($j,&DWP(4,$j));
&mov (&DWP($frame,"esp",$num,4),"edx"); # tp[num-1]=
&cmp ($j,$_bpend);
&mov (&DWP($frame+4,"esp",$num,4),"eax"); # tp[num]=
&je (&label("common_tail"));
&mov ($word,&DWP(0,$j)); # bp[i+1]
&mov ($inp,$_ap);
&mov ($_bp,$j); # &bp[++i]
&xor ($j,$j);
&xor ("edx","edx");
&mov ("eax",&DWP(0,$inp));
&jmp (&label("1stmadd"));
&set_label("bn_sqr_mont",16);
$sbit=$num;
&mov ($_num,$num);
&mov ($_bp,$j); # i=0
&mov ("eax",$word); # ap[0]
&mul ($word); # ap[0]*ap[0]
&mov (&DWP($frame,"esp"),"eax"); # tp[0]=
&mov ($sbit,"edx");
&shr ("edx",1);
&and ($sbit,1);
&inc ($j);
&set_label("sqr",16);
&mov ("eax",&DWP(0,$inp,$j,4)); # ap[j]
&mov ($carry,"edx");
&mul ($word); # ap[j]*ap[0]
&add ("eax",$carry);
&lea ($j,&DWP(1,$j));
&adc ("edx",0);
&lea ($carry,&DWP(0,$sbit,"eax",2));
&shr ("eax",31);
&cmp ($j,$_num);
&mov ($sbit,"eax");
&mov (&DWP($frame-4,"esp",$j,4),$carry); # tp[j]=
&jl (&label("sqr"));
&mov ("eax",&DWP(0,$inp,$j,4)); # ap[num-1]
&mov ($carry,"edx");
&mul ($word); # ap[num-1]*ap[0]
&add ("eax",$carry);
&mov ($word,$_n0);
&adc ("edx",0);
&mov ($inp,$_np);
&lea ($carry,&DWP(0,$sbit,"eax",2));
&imul ($word,&DWP($frame,"esp")); # n0*tp[0]
&shr ("eax",31);
&mov (&DWP($frame,"esp",$j,4),$carry); # tp[num-1]=
&lea ($carry,&DWP(0,"eax","edx",2));
&mov ("eax",&DWP(0,$inp)); # np[0]
&shr ("edx",31);
&mov (&DWP($frame+4,"esp",$j,4),$carry); # tp[num]=
&mov (&DWP($frame+8,"esp",$j,4),"edx"); # tp[num+1]=
&mul ($word); # np[0]*m
&add ("eax",&DWP($frame,"esp")); # +=tp[0]
&mov ($num,$j);
&adc ("edx",0);
&mov ("eax",&DWP(4,$inp)); # np[1]
&mov ($j,1);
&set_label("3rdmadd",16);
&mov ($carry,"edx");
&mul ($word); # np[j]*m
&add ($carry,&DWP($frame,"esp",$j,4)); # +=tp[j]
&adc ("edx",0);
&add ($carry,"eax");
&mov ("eax",&DWP(4,$inp,$j,4)); # np[j+1]
&adc ("edx",0);
&mov (&DWP($frame-4,"esp",$j,4),$carry); # tp[j-1]=
&mov ($carry,"edx");
&mul ($word); # np[j+1]*m
&add ($carry,&DWP($frame+4,"esp",$j,4)); # +=tp[j+1]
&lea ($j,&DWP(2,$j));
&adc ("edx",0);
&add ($carry,"eax");
&mov ("eax",&DWP(0,$inp,$j,4)); # np[j+2]
&adc ("edx",0);
&cmp ($j,$num);
&mov (&DWP($frame-8,"esp",$j,4),$carry); # tp[j]=
&jl (&label("3rdmadd"));
&mov ($carry,"edx");
&mul ($word); # np[j]*m
&add ($carry,&DWP($frame,"esp",$num,4)); # +=tp[num-1]
&adc ("edx",0);
&add ($carry,"eax");
&adc ("edx",0);
&mov (&DWP($frame-4,"esp",$num,4),$carry); # tp[num-2]=
&mov ($j,$_bp); # i
&xor ("eax","eax");
&mov ($inp,$_ap);
&add ("edx",&DWP($frame+4,"esp",$num,4)); # carry+=tp[num]
&adc ("eax",&DWP($frame+8,"esp",$num,4)); # +=tp[num+1]
&mov (&DWP($frame,"esp",$num,4),"edx"); # tp[num-1]=
&cmp ($j,$num);
&mov (&DWP($frame+4,"esp",$num,4),"eax"); # tp[num]=
&je (&label("common_tail"));
&mov ($word,&DWP(4,$inp,$j,4)); # ap[i]
&lea ($j,&DWP(1,$j));
&mov ("eax",$word);
&mov ($_bp,$j); # ++i
&mul ($word); # ap[i]*ap[i]
&add ("eax",&DWP($frame,"esp",$j,4)); # +=tp[i]
&adc ("edx",0);
&mov (&DWP($frame,"esp",$j,4),"eax"); # tp[i]=
&xor ($carry,$carry);
&cmp ($j,$num);
&lea ($j,&DWP(1,$j));
&je (&label("sqrlast"));
&mov ($sbit,"edx"); # zaps $num
&shr ("edx",1);
&and ($sbit,1);
&set_label("sqradd",16);
&mov ("eax",&DWP(0,$inp,$j,4)); # ap[j]
&mov ($carry,"edx");
&mul ($word); # ap[j]*ap[i]
&add ("eax",$carry);
&lea ($carry,&DWP(0,"eax","eax"));
&adc ("edx",0);
&shr ("eax",31);
&add ($carry,&DWP($frame,"esp",$j,4)); # +=tp[j]
&lea ($j,&DWP(1,$j));
&adc ("eax",0);
&add ($carry,$sbit);
&adc ("eax",0);
&cmp ($j,$_num);
&mov (&DWP($frame-4,"esp",$j,4),$carry); # tp[j]=
&mov ($sbit,"eax");
&jle (&label("sqradd"));
&mov ($carry,"edx");
&add ("edx","edx");
&shr ($carry,31);
&add ("edx",$sbit);
&adc ($carry,0);
&set_label("sqrlast");
&mov ($word,$_n0);
&mov ($inp,$_np);
&imul ($word,&DWP($frame,"esp")); # n0*tp[0]
&add ("edx",&DWP($frame,"esp",$j,4)); # +=tp[num]
&mov ("eax",&DWP(0,$inp)); # np[0]
&adc ($carry,0);
&mov (&DWP($frame,"esp",$j,4),"edx"); # tp[num]=
&mov (&DWP($frame+4,"esp",$j,4),$carry); # tp[num+1]=
&mul ($word); # np[0]*m
&add ("eax",&DWP($frame,"esp")); # +=tp[0]
&lea ($num,&DWP(-1,$j));
&adc ("edx",0);
&mov ($j,1);
&mov ("eax",&DWP(4,$inp)); # np[1]
&jmp (&label("3rdmadd"));
}
&set_label("common_tail",16);
&mov ($np,$_np); # load modulus pointer
&mov ($rp,$_rp); # load result pointer
&lea ($tp,&DWP($frame,"esp")); # [$ap and $bp are zapped]
&mov ("eax",&DWP(0,$tp)); # tp[0]
&mov ($j,$num); # j=num-1
&xor ($i,$i); # i=0 and clear CF!
&set_label("sub",16);
&sbb ("eax",&DWP(0,$np,$i,4));
&mov (&DWP(0,$rp,$i,4),"eax"); # rp[i]=tp[i]-np[i]
&dec ($j); # doesn't affect CF!
&mov ("eax",&DWP(4,$tp,$i,4)); # tp[i+1]
&lea ($i,&DWP(1,$i)); # i++
&jge (&label("sub"));
&sbb ("eax",0); # handle upmost overflow bit
&and ($tp,"eax");
&not ("eax");
&mov ($np,$rp);
&and ($np,"eax");
&or ($tp,$np); # tp=carry?tp:rp
&set_label("copy",16); # copy or in-place refresh
&mov ("eax",&DWP(0,$tp,$num,4));
&mov (&DWP(0,$rp,$num,4),"eax"); # rp[i]=tp[i]
&mov (&DWP($frame,"esp",$num,4),$j); # zap temporary vector
&dec ($num);
&jge (&label("copy"));
&mov ("esp",$_sp); # pull saved stack pointer
&mov ("eax",1);
&set_label("just_leave");
&function_end("bn_mul_mont");
&asciz("Montgomery Multiplication for x86, CRYPTOGAMS by <appro\@openssl.org>");
&asm_finish();
close STDOUT;
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