| Index: openssl/crypto/bn/asm/armv4-mont.pl
|
| ===================================================================
|
| --- openssl/crypto/bn/asm/armv4-mont.pl (revision 0)
|
| +++ openssl/crypto/bn/asm/armv4-mont.pl (revision 0)
|
| @@ -0,0 +1,201 @@
|
| +#!/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/.
|
| +# ====================================================================
|
| +
|
| +# January 2007.
|
| +
|
| +# Montgomery multiplication for ARMv4.
|
| +#
|
| +# Performance improvement naturally varies among CPU implementations
|
| +# and compilers. The code was observed to provide +65-35% improvement
|
| +# [depending on key length, less for longer keys] on ARM920T, and
|
| +# +115-80% on Intel IXP425. This is compared to pre-bn_mul_mont code
|
| +# base and compiler generated code with in-lined umull and even umlal
|
| +# instructions. The latter means that this code didn't really have an
|
| +# "advantage" of utilizing some "secret" instruction.
|
| +#
|
| +# The code is interoperable with Thumb ISA and is rather compact, less
|
| +# than 1/2KB. Windows CE port would be trivial, as it's exclusively
|
| +# about decorations, ABI and instruction syntax are identical.
|
| +
|
| +$num="r0"; # starts as num argument, but holds &tp[num-1]
|
| +$ap="r1";
|
| +$bp="r2"; $bi="r2"; $rp="r2";
|
| +$np="r3";
|
| +$tp="r4";
|
| +$aj="r5";
|
| +$nj="r6";
|
| +$tj="r7";
|
| +$n0="r8";
|
| +########### # r9 is reserved by ELF as platform specific, e.g. TLS pointer
|
| +$alo="r10"; # sl, gcc uses it to keep @GOT
|
| +$ahi="r11"; # fp
|
| +$nlo="r12"; # ip
|
| +########### # r13 is stack pointer
|
| +$nhi="r14"; # lr
|
| +########### # r15 is program counter
|
| +
|
| +#### argument block layout relative to &tp[num-1], a.k.a. $num
|
| +$_rp="$num,#12*4";
|
| +# ap permanently resides in r1
|
| +$_bp="$num,#13*4";
|
| +# np permanently resides in r3
|
| +$_n0="$num,#14*4";
|
| +$_num="$num,#15*4"; $_bpend=$_num;
|
| +
|
| +$code=<<___;
|
| +.text
|
| +
|
| +.global bn_mul_mont
|
| +.type bn_mul_mont,%function
|
| +
|
| +.align 2
|
| +bn_mul_mont:
|
| + stmdb sp!,{r0,r2} @ sp points at argument block
|
| + ldr $num,[sp,#3*4] @ load num
|
| + cmp $num,#2
|
| + movlt r0,#0
|
| + addlt sp,sp,#2*4
|
| + blt .Labrt
|
| +
|
| + stmdb sp!,{r4-r12,lr} @ save 10 registers
|
| +
|
| + mov $num,$num,lsl#2 @ rescale $num for byte count
|
| + sub sp,sp,$num @ alloca(4*num)
|
| + sub sp,sp,#4 @ +extra dword
|
| + sub $num,$num,#4 @ "num=num-1"
|
| + add $tp,$bp,$num @ &bp[num-1]
|
| +
|
| + add $num,sp,$num @ $num to point at &tp[num-1]
|
| + ldr $n0,[$_n0] @ &n0
|
| + ldr $bi,[$bp] @ bp[0]
|
| + ldr $aj,[$ap],#4 @ ap[0],ap++
|
| + ldr $nj,[$np],#4 @ np[0],np++
|
| + ldr $n0,[$n0] @ *n0
|
| + str $tp,[$_bpend] @ save &bp[num]
|
| +
|
| + umull $alo,$ahi,$aj,$bi @ ap[0]*bp[0]
|
| + str $n0,[$_n0] @ save n0 value
|
| + mul $n0,$alo,$n0 @ "tp[0]"*n0
|
| + mov $nlo,#0
|
| + umlal $alo,$nlo,$nj,$n0 @ np[0]*n0+"t[0]"
|
| + mov $tp,sp
|
| +
|
| +.L1st:
|
| + ldr $aj,[$ap],#4 @ ap[j],ap++
|
| + mov $alo,$ahi
|
| + mov $ahi,#0
|
| + umlal $alo,$ahi,$aj,$bi @ ap[j]*bp[0]
|
| + ldr $nj,[$np],#4 @ np[j],np++
|
| + mov $nhi,#0
|
| + umlal $nlo,$nhi,$nj,$n0 @ np[j]*n0
|
| + adds $nlo,$nlo,$alo
|
| + str $nlo,[$tp],#4 @ tp[j-1]=,tp++
|
| + adc $nlo,$nhi,#0
|
| + cmp $tp,$num
|
| + bne .L1st
|
| +
|
| + adds $nlo,$nlo,$ahi
|
| + mov $nhi,#0
|
| + adc $nhi,$nhi,#0
|
| + ldr $tp,[$_bp] @ restore bp
|
| + str $nlo,[$num] @ tp[num-1]=
|
| + ldr $n0,[$_n0] @ restore n0
|
| + str $nhi,[$num,#4] @ tp[num]=
|
| +
|
| +.Louter:
|
| + sub $tj,$num,sp @ "original" $num-1 value
|
| + sub $ap,$ap,$tj @ "rewind" ap to &ap[1]
|
| + sub $np,$np,$tj @ "rewind" np to &np[1]
|
| + ldr $bi,[$tp,#4]! @ *(++bp)
|
| + ldr $aj,[$ap,#-4] @ ap[0]
|
| + ldr $nj,[$np,#-4] @ np[0]
|
| + ldr $alo,[sp] @ tp[0]
|
| + ldr $tj,[sp,#4] @ tp[1]
|
| +
|
| + mov $ahi,#0
|
| + umlal $alo,$ahi,$aj,$bi @ ap[0]*bp[i]+tp[0]
|
| + str $tp,[$_bp] @ save bp
|
| + mul $n0,$alo,$n0
|
| + mov $nlo,#0
|
| + umlal $alo,$nlo,$nj,$n0 @ np[0]*n0+"tp[0]"
|
| + mov $tp,sp
|
| +
|
| +.Linner:
|
| + ldr $aj,[$ap],#4 @ ap[j],ap++
|
| + adds $alo,$ahi,$tj @ +=tp[j]
|
| + mov $ahi,#0
|
| + umlal $alo,$ahi,$aj,$bi @ ap[j]*bp[i]
|
| + ldr $nj,[$np],#4 @ np[j],np++
|
| + mov $nhi,#0
|
| + umlal $nlo,$nhi,$nj,$n0 @ np[j]*n0
|
| + ldr $tj,[$tp,#8] @ tp[j+1]
|
| + adc $ahi,$ahi,#0
|
| + adds $nlo,$nlo,$alo
|
| + str $nlo,[$tp],#4 @ tp[j-1]=,tp++
|
| + adc $nlo,$nhi,#0
|
| + cmp $tp,$num
|
| + bne .Linner
|
| +
|
| + adds $nlo,$nlo,$ahi
|
| + mov $nhi,#0
|
| + adc $nhi,$nhi,#0
|
| + adds $nlo,$nlo,$tj
|
| + adc $nhi,$nhi,#0
|
| + ldr $tp,[$_bp] @ restore bp
|
| + ldr $tj,[$_bpend] @ restore &bp[num]
|
| + str $nlo,[$num] @ tp[num-1]=
|
| + ldr $n0,[$_n0] @ restore n0
|
| + str $nhi,[$num,#4] @ tp[num]=
|
| +
|
| + cmp $tp,$tj
|
| + bne .Louter
|
| +
|
| + ldr $rp,[$_rp] @ pull rp
|
| + add $num,$num,#4 @ $num to point at &tp[num]
|
| + sub $aj,$num,sp @ "original" num value
|
| + mov $tp,sp @ "rewind" $tp
|
| + mov $ap,$tp @ "borrow" $ap
|
| + sub $np,$np,$aj @ "rewind" $np to &np[0]
|
| +
|
| + subs $tj,$tj,$tj @ "clear" carry flag
|
| +.Lsub: ldr $tj,[$tp],#4
|
| + ldr $nj,[$np],#4
|
| + sbcs $tj,$tj,$nj @ tp[j]-np[j]
|
| + str $tj,[$rp],#4 @ rp[j]=
|
| + teq $tp,$num @ preserve carry
|
| + bne .Lsub
|
| + sbcs $nhi,$nhi,#0 @ upmost carry
|
| + mov $tp,sp @ "rewind" $tp
|
| + sub $rp,$rp,$aj @ "rewind" $rp
|
| +
|
| + and $ap,$tp,$nhi
|
| + bic $np,$rp,$nhi
|
| + orr $ap,$ap,$np @ ap=borrow?tp:rp
|
| +
|
| +.Lcopy: ldr $tj,[$ap],#4 @ copy or in-place refresh
|
| + str sp,[$tp],#4 @ zap tp
|
| + str $tj,[$rp],#4
|
| + cmp $tp,$num
|
| + bne .Lcopy
|
| +
|
| + add sp,$num,#4 @ skip over tp[num+1]
|
| + ldmia sp!,{r4-r12,lr} @ restore registers
|
| + add sp,sp,#2*4 @ skip over {r0,r2}
|
| + mov r0,#1
|
| +.Labrt: tst lr,#1
|
| + moveq pc,lr @ be binary compatible with V4, yet
|
| + bx lr @ interoperable with Thumb ISA:-)
|
| +.size bn_mul_mont,.-bn_mul_mont
|
| +.asciz "Montgomery multiplication for ARMv4, CRYPTOGAMS by <appro\@openssl.org>"
|
| +.align 2
|
| +___
|
| +
|
| +$code =~ s/\bbx\s+lr\b/.word\t0xe12fff1e/gm; # make it possible to compile with -march=armv4
|
| +print $code;
|
| +close STDOUT;
|
|
|