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; |