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Diffstat (limited to 'crypto/bn/asm/armv4-mont.pl')
| -rwxr-xr-x | crypto/bn/asm/armv4-mont.pl | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/crypto/bn/asm/armv4-mont.pl b/crypto/bn/asm/armv4-mont.pl new file mode 100755 index 0000000..05d5dc1 --- /dev/null +++ b/crypto/bn/asm/armv4-mont.pl @@ -0,0 +1,200 @@ +#!/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,$num,#4 @ skip over tp[num+1] + ldmia sp!,{r4-r12,lr} @ restore registers + add sp,sp,#2*4 @ skip over {r0,r2} + mov r0,#1 +.Labrt: tst lr,#1 + moveq pc,lr @ be binary compatible with V4, yet + bx lr @ interoperable with Thumb ISA:-) +.size bn_mul_mont,.-bn_mul_mont +.asciz "Montgomery multiplication for ARMv4, CRYPTOGAMS by <appro\@openssl.org>" +___ + +$code =~ s/\bbx\s+lr\b/.word\t0xe12fff1e/gm; # make it possible to compile with -march=armv4 +print $code; +close STDOUT; |
