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boringssl/crypto/fipsmodule/bn/asm/armv8-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@openssl.org> 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/.
# ====================================================================
# March 2015
#
# "Teaser" Montgomery multiplication module for ARMv8. Needs more
# work. While it does improve RSA sign performance by 20-30% (less for
# longer keys) on most processors, for some reason RSA2048 is not
# faster and RSA4096 goes 15-20% slower on Cortex-A57. Multiplication
# instruction issue rate is limited on processor in question, meaning
# that dedicated squaring procedure is a must. Well, actually all
# contemporary AArch64 processors seem to have limited multiplication
# issue rate, i.e. they can't issue multiplication every cycle, which
# explains moderate improvement coefficients in comparison to
# compiler-generated code. Recall that compiler is instructed to use
# umulh and therefore uses same amount of multiplication instructions
# to do the job. Assembly's edge is to minimize number of "collateral"
# instructions and of course instruction scheduling.
#
# April 2015
#
# Squaring procedure that handles lengths divisible by 8 improves
# RSA/DSA performance by 25-40-60% depending on processor and key
# length. Overall improvement coefficients are always positive in
# comparison to compiler-generated code. On Cortex-A57 improvement
# is still modest on longest key lengths, while others exhibit e.g.
# 50-70% improvement for RSA4096 sign. RSA2048 sign is ~25% faster
# on Cortex-A57 and ~60-100% faster on others.
$flavour = shift;
$output = shift;
$0 =~ m/(.*[\/\\])[^\/\\]+$/; $dir=$1;
( $xlate="${dir}arm-xlate.pl" and -f $xlate ) or
( $xlate="${dir}../../../perlasm/arm-xlate.pl" and -f $xlate) or
die "can't locate arm-xlate.pl";
open OUT,"| \"$^X\" $xlate $flavour $output";
*STDOUT=*OUT;
($lo0,$hi0,$aj,$m0,$alo,$ahi,
$lo1,$hi1,$nj,$m1,$nlo,$nhi,
$ovf, $i,$j,$tp,$tj) = map("x$_",6..17,19..24);
# int bn_mul_mont(
$rp="x0"; # BN_ULONG *rp,
$ap="x1"; # const BN_ULONG *ap,
$bp="x2"; # const BN_ULONG *bp,
$np="x3"; # const BN_ULONG *np,
$n0="x4"; # const BN_ULONG *n0,
$num="x5"; # int num);
$code.=<<___;
.text
.globl bn_mul_mont
.type bn_mul_mont,%function
.align 5
bn_mul_mont:
tst $num,#7
b.eq __bn_sqr8x_mont
tst $num,#3
b.eq __bn_mul4x_mont
.Lmul_mont:
stp x29,x30,[sp,#-64]!
add x29,sp,#0
stp x19,x20,[sp,#16]
stp x21,x22,[sp,#32]
stp x23,x24,[sp,#48]
ldr $m0,[$bp],#8 // bp[0]
sub $tp,sp,$num,lsl#3
ldp $hi0,$aj,[$ap],#16 // ap[0..1]
lsl $num,$num,#3
ldr $n0,[$n0] // *n0
and $tp,$tp,#-16 // ABI says so
ldp $hi1,$nj,[$np],#16 // np[0..1]
mul $lo0,$hi0,$m0 // ap[0]*bp[0]
sub $j,$num,#16 // j=num-2
umulh $hi0,$hi0,$m0
mul $alo,$aj,$m0 // ap[1]*bp[0]
umulh $ahi,$aj,$m0
mul $m1,$lo0,$n0 // "tp[0]"*n0
mov sp,$tp // alloca
// (*) mul $lo1,$hi1,$m1 // np[0]*m1
umulh $hi1,$hi1,$m1
mul $nlo,$nj,$m1 // np[1]*m1
// (*) adds $lo1,$lo1,$lo0 // discarded
// (*) As for removal of first multiplication and addition
// instructions. The outcome of first addition is
// guaranteed to be zero, which leaves two computationally
// significant outcomes: it either carries or not. Then
// question is when does it carry? Is there alternative
// way to deduce it? If you follow operations, you can
// observe that condition for carry is quite simple:
// $lo0 being non-zero. So that carry can be calculated
// by adding -1 to $lo0. That's what next instruction does.
subs xzr,$lo0,#1 // (*)
umulh $nhi,$nj,$m1
adc $hi1,$hi1,xzr
cbz $j,.L1st_skip
.L1st:
ldr $aj,[$ap],#8
adds $lo0,$alo,$hi0
sub $j,$j,#8 // j--
adc $hi0,$ahi,xzr
ldr $nj,[$np],#8
adds $lo1,$nlo,$hi1
mul $alo,$aj,$m0 // ap[j]*bp[0]
adc $hi1,$nhi,xzr
umulh $ahi,$aj,$m0
adds $lo1,$lo1,$lo0
mul $nlo,$nj,$m1 // np[j]*m1
adc $hi1,$hi1,xzr
umulh $nhi,$nj,$m1
str $lo1,[$tp],#8 // tp[j-1]
cbnz $j,.L1st
.L1st_skip:
adds $lo0,$alo,$hi0
sub $ap,$ap,$num // rewind $ap
adc $hi0,$ahi,xzr
adds $lo1,$nlo,$hi1
sub $np,$np,$num // rewind $np
adc $hi1,$nhi,xzr
adds $lo1,$lo1,$lo0
sub $i,$num,#8 // i=num-1
adcs $hi1,$hi1,$hi0
adc $ovf,xzr,xzr // upmost overflow bit
stp $lo1,$hi1,[$tp]
.Louter:
ldr $m0,[$bp],#8 // bp[i]
ldp $hi0,$aj,[$ap],#16
ldr $tj,[sp] // tp[0]
add $tp,sp,#8
mul $lo0,$hi0,$m0 // ap[0]*bp[i]
sub $j,$num,#16 // j=num-2
umulh $hi0,$hi0,$m0
ldp $hi1,$nj,[$np],#16
mul $alo,$aj,$m0 // ap[1]*bp[i]
adds $lo0,$lo0,$tj
umulh $ahi,$aj,$m0
adc $hi0,$hi0,xzr
mul $m1,$lo0,$n0
sub $i,$i,#8 // i--
// (*) mul $lo1,$hi1,$m1 // np[0]*m1
umulh $hi1,$hi1,$m1
mul $nlo,$nj,$m1 // np[1]*m1
// (*) adds $lo1,$lo1,$lo0
subs xzr,$lo0,#1 // (*)
umulh $nhi,$nj,$m1
cbz $j,.Linner_skip
.Linner:
ldr $aj,[$ap],#8
adc $hi1,$hi1,xzr
ldr $tj,[$tp],#8 // tp[j]
adds $lo0,$alo,$hi0
sub $j,$j,#8 // j--
adc $hi0,$ahi,xzr
adds $lo1,$nlo,$hi1
ldr $nj,[$np],#8
adc $hi1,$nhi,xzr
mul $alo,$aj,$m0 // ap[j]*bp[i]
adds $lo0,$lo0,$tj
umulh $ahi,$aj,$m0
adc $hi0,$hi0,xzr
mul $nlo,$nj,$m1 // np[j]*m1
adds $lo1,$lo1,$lo0
umulh $nhi,$nj,$m1
str $lo1,[$tp,#-16] // tp[j-1]
cbnz $j,.Linner
.Linner_skip:
ldr $tj,[$tp],#8 // tp[j]
adc $hi1,$hi1,xzr
adds $lo0,$alo,$hi0
sub $ap,$ap,$num // rewind $ap
adc $hi0,$ahi,xzr
adds $lo1,$nlo,$hi1
sub $np,$np,$num // rewind $np
adcs $hi1,$nhi,$ovf
adc $ovf,xzr,xzr
adds $lo0,$lo0,$tj
adc $hi0,$hi0,xzr
adds $lo1,$lo1,$lo0
adcs $hi1,$hi1,$hi0
adc $ovf,$ovf,xzr // upmost overflow bit
stp $lo1,$hi1,[$tp,#-16]
cbnz $i,.Louter
// Final step. We see if result is larger than modulus, and
// if it is, subtract the modulus. But comparison implies
// subtraction. So we subtract modulus, see if it borrowed,
// and conditionally copy original value.
ldr $tj,[sp] // tp[0]
add $tp,sp,#8
ldr $nj,[$np],#8 // np[0]
subs $j,$num,#8 // j=num-1 and clear borrow
mov $ap,$rp
.Lsub:
sbcs $aj,$tj,$nj // tp[j]-np[j]
ldr $tj,[$tp],#8
sub $j,$j,#8 // j--
ldr $nj,[$np],#8
str $aj,[$ap],#8 // rp[j]=tp[j]-np[j]
cbnz $j,.Lsub
sbcs $aj,$tj,$nj
sbcs $ovf,$ovf,xzr // did it borrow?
str $aj,[$ap],#8 // rp[num-1]
ldr $tj,[sp] // tp[0]
add $tp,sp,#8
ldr $aj,[$rp],#8 // rp[0]
sub $num,$num,#8 // num--
nop
.Lcond_copy:
sub $num,$num,#8 // num--
csel $nj,$tj,$aj,lo // did it borrow?
ldr $tj,[$tp],#8
ldr $aj,[$rp],#8
str xzr,[$tp,#-16] // wipe tp
str $nj,[$rp,#-16]
cbnz $num,.Lcond_copy
csel $nj,$tj,$aj,lo
str xzr,[$tp,#-8] // wipe tp
str $nj,[$rp,#-8]
ldp x19,x20,[x29,#16]
mov sp,x29
ldp x21,x22,[x29,#32]
mov x0,#1
ldp x23,x24,[x29,#48]
ldr x29,[sp],#64
ret
.size bn_mul_mont,.-bn_mul_mont
___
{
########################################################################
# Following is ARMv8 adaptation of sqrx8x_mont from x86_64-mont5 module.
my ($a0,$a1,$a2,$a3,$a4,$a5,$a6,$a7)=map("x$_",(6..13));
my ($t0,$t1,$t2,$t3)=map("x$_",(14..17));
my ($acc0,$acc1,$acc2,$acc3,$acc4,$acc5,$acc6,$acc7)=map("x$_",(19..26));
my ($cnt,$carry,$topmost)=("x27","x28","x30");
my ($tp,$ap_end,$na0)=($bp,$np,$carry);
$code.=<<___;
.type __bn_sqr8x_mont,%function
.align 5
__bn_sqr8x_mont:
cmp $ap,$bp
b.ne __bn_mul4x_mont
.Lsqr8x_mont:
stp x29,x30,[sp,#-128]!
add x29,sp,#0
stp x19,x20,[sp,#16]
stp x21,x22,[sp,#32]
stp x23,x24,[sp,#48]
stp x25,x26,[sp,#64]
stp x27,x28,[sp,#80]
stp $rp,$np,[sp,#96] // offload rp and np
ldp $a0,$a1,[$ap,#8*0]
ldp $a2,$a3,[$ap,#8*2]
ldp $a4,$a5,[$ap,#8*4]
ldp $a6,$a7,[$ap,#8*6]
sub $tp,sp,$num,lsl#4
lsl $num,$num,#3
ldr $n0,[$n0] // *n0
mov sp,$tp // alloca
sub $cnt,$num,#8*8
b .Lsqr8x_zero_start
.Lsqr8x_zero:
sub $cnt,$cnt,#8*8
stp xzr,xzr,[$tp,#8*0]
stp xzr,xzr,[$tp,#8*2]
stp xzr,xzr,[$tp,#8*4]
stp xzr,xzr,[$tp,#8*6]
.Lsqr8x_zero_start:
stp xzr,xzr,[$tp,#8*8]
stp xzr,xzr,[$tp,#8*10]
stp xzr,xzr,[$tp,#8*12]
stp xzr,xzr,[$tp,#8*14]
add $tp,$tp,#8*16
cbnz $cnt,.Lsqr8x_zero
add $ap_end,$ap,$num
add $ap,$ap,#8*8
mov $acc0,xzr
mov $acc1,xzr
mov $acc2,xzr
mov $acc3,xzr
mov $acc4,xzr
mov $acc5,xzr
mov $acc6,xzr
mov $acc7,xzr
mov $tp,sp
str $n0,[x29,#112] // offload n0
// Multiply everything but a[i]*a[i]
.align 4
.Lsqr8x_outer_loop:
// a[1]a[0] (i)
// a[2]a[0]
// a[3]a[0]
// a[4]a[0]
// a[5]a[0]
// a[6]a[0]
// a[7]a[0]
// a[2]a[1] (ii)
// a[3]a[1]
// a[4]a[1]
// a[5]a[1]
// a[6]a[1]
// a[7]a[1]
// a[3]a[2] (iii)
// a[4]a[2]
// a[5]a[2]
// a[6]a[2]
// a[7]a[2]
// a[4]a[3] (iv)
// a[5]a[3]
// a[6]a[3]
// a[7]a[3]
// a[5]a[4] (v)
// a[6]a[4]
// a[7]a[4]
// a[6]a[5] (vi)
// a[7]a[5]
// a[7]a[6] (vii)
mul $t0,$a1,$a0 // lo(a[1..7]*a[0]) (i)
mul $t1,$a2,$a0
mul $t2,$a3,$a0
mul $t3,$a4,$a0
adds $acc1,$acc1,$t0 // t[1]+lo(a[1]*a[0])
mul $t0,$a5,$a0
adcs $acc2,$acc2,$t1
mul $t1,$a6,$a0
adcs $acc3,$acc3,$t2
mul $t2,$a7,$a0
adcs $acc4,$acc4,$t3
umulh $t3,$a1,$a0 // hi(a[1..7]*a[0])
adcs $acc5,$acc5,$t0
umulh $t0,$a2,$a0
adcs $acc6,$acc6,$t1
umulh $t1,$a3,$a0
adcs $acc7,$acc7,$t2
umulh $t2,$a4,$a0
stp $acc0,$acc1,[$tp],#8*2 // t[0..1]
adc $acc0,xzr,xzr // t[8]
adds $acc2,$acc2,$t3 // t[2]+lo(a[1]*a[0])
umulh $t3,$a5,$a0
adcs $acc3,$acc3,$t0
umulh $t0,$a6,$a0
adcs $acc4,$acc4,$t1
umulh $t1,$a7,$a0
adcs $acc5,$acc5,$t2
mul $t2,$a2,$a1 // lo(a[2..7]*a[1]) (ii)
adcs $acc6,$acc6,$t3
mul $t3,$a3,$a1
adcs $acc7,$acc7,$t0
mul $t0,$a4,$a1
adc $acc0,$acc0,$t1
mul $t1,$a5,$a1
adds $acc3,$acc3,$t2
mul $t2,$a6,$a1
adcs $acc4,$acc4,$t3
mul $t3,$a7,$a1
adcs $acc5,$acc5,$t0
umulh $t0,$a2,$a1 // hi(a[2..7]*a[1])
adcs $acc6,$acc6,$t1
umulh $t1,$a3,$a1
adcs $acc7,$acc7,$t2
umulh $t2,$a4,$a1
adcs $acc0,$acc0,$t3
umulh $t3,$a5,$a1
stp $acc2,$acc3,[$tp],#8*2 // t[2..3]
adc $acc1,xzr,xzr // t[9]
adds $acc4,$acc4,$t0
umulh $t0,$a6,$a1
adcs $acc5,$acc5,$t1
umulh $t1,$a7,$a1
adcs $acc6,$acc6,$t2
mul $t2,$a3,$a2 // lo(a[3..7]*a[2]) (iii)
adcs $acc7,$acc7,$t3
mul $t3,$a4,$a2
adcs $acc0,$acc0,$t0
mul $t0,$a5,$a2
adc $acc1,$acc1,$t1
mul $t1,$a6,$a2
adds $acc5,$acc5,$t2
mul $t2,$a7,$a2
adcs $acc6,$acc6,$t3
umulh $t3,$a3,$a2 // hi(a[3..7]*a[2])
adcs $acc7,$acc7,$t0
umulh $t0,$a4,$a2
adcs $acc0,$acc0,$t1
umulh $t1,$a5,$a2
adcs $acc1,$acc1,$t2
umulh $t2,$a6,$a2
stp $acc4,$acc5,[$tp],#8*2 // t[4..5]
adc $acc2,xzr,xzr // t[10]
adds $acc6,$acc6,$t3
umulh $t3,$a7,$a2
adcs $acc7,$acc7,$t0
mul $t0,$a4,$a3 // lo(a[4..7]*a[3]) (iv)
adcs $acc0,$acc0,$t1
mul $t1,$a5,$a3
adcs $acc1,$acc1,$t2
mul $t2,$a6,$a3
adc $acc2,$acc2,$t3
mul $t3,$a7,$a3
adds $acc7,$acc7,$t0
umulh $t0,$a4,$a3 // hi(a[4..7]*a[3])
adcs $acc0,$acc0,$t1
umulh $t1,$a5,$a3
adcs $acc1,$acc1,$t2
umulh $t2,$a6,$a3
adcs $acc2,$acc2,$t3
umulh $t3,$a7,$a3
stp $acc6,$acc7,[$tp],#8*2 // t[6..7]
adc $acc3,xzr,xzr // t[11]
adds $acc0,$acc0,$t0
mul $t0,$a5,$a4 // lo(a[5..7]*a[4]) (v)
adcs $acc1,$acc1,$t1
mul $t1,$a6,$a4
adcs $acc2,$acc2,$t2
mul $t2,$a7,$a4
adc $acc3,$acc3,$t3
umulh $t3,$a5,$a4 // hi(a[5..7]*a[4])
adds $acc1,$acc1,$t0
umulh $t0,$a6,$a4
adcs $acc2,$acc2,$t1
umulh $t1,$a7,$a4
adcs $acc3,$acc3,$t2
mul $t2,$a6,$a5 // lo(a[6..7]*a[5]) (vi)
adc $acc4,xzr,xzr // t[12]
adds $acc2,$acc2,$t3
mul $t3,$a7,$a5
adcs $acc3,$acc3,$t0
umulh $t0,$a6,$a5 // hi(a[6..7]*a[5])
adc $acc4,$acc4,$t1
umulh $t1,$a7,$a5
adds $acc3,$acc3,$t2
mul $t2,$a7,$a6 // lo(a[7]*a[6]) (vii)
adcs $acc4,$acc4,$t3
umulh $t3,$a7,$a6 // hi(a[7]*a[6])
adc $acc5,xzr,xzr // t[13]
adds $acc4,$acc4,$t0
sub $cnt,$ap_end,$ap // done yet?
adc $acc5,$acc5,$t1
adds $acc5,$acc5,$t2
sub $t0,$ap_end,$num // rewinded ap
adc $acc6,xzr,xzr // t[14]
add $acc6,$acc6,$t3
cbz $cnt,.Lsqr8x_outer_break
mov $n0,$a0
ldp $a0,$a1,[$tp,#8*0]
ldp $a2,$a3,[$tp,#8*2]
ldp $a4,$a5,[$tp,#8*4]
ldp $a6,$a7,[$tp,#8*6]
adds $acc0,$acc0,$a0
adcs $acc1,$acc1,$a1
ldp $a0,$a1,[$ap,#8*0]
adcs $acc2,$acc2,$a2
adcs $acc3,$acc3,$a3
ldp $a2,$a3,[$ap,#8*2]
adcs $acc4,$acc4,$a4
adcs $acc5,$acc5,$a5
ldp $a4,$a5,[$ap,#8*4]
adcs $acc6,$acc6,$a6
mov $rp,$ap
adcs $acc7,xzr,$a7
ldp $a6,$a7,[$ap,#8*6]
add $ap,$ap,#8*8
//adc $carry,xzr,xzr // moved below
mov $cnt,#-8*8
// a[8]a[0]
// a[9]a[0]
// a[a]a[0]
// a[b]a[0]
// a[c]a[0]
// a[d]a[0]
// a[e]a[0]
// a[f]a[0]
// a[8]a[1]
// a[f]a[1]........................
// a[8]a[2]
// a[f]a[2]........................
// a[8]a[3]
// a[f]a[3]........................
// a[8]a[4]
// a[f]a[4]........................
// a[8]a[5]
// a[f]a[5]........................
// a[8]a[6]
// a[f]a[6]........................
// a[8]a[7]
// a[f]a[7]........................
.Lsqr8x_mul:
mul $t0,$a0,$n0
adc $carry,xzr,xzr // carry bit, modulo-scheduled
mul $t1,$a1,$n0
add $cnt,$cnt,#8
mul $t2,$a2,$n0
mul $t3,$a3,$n0
adds $acc0,$acc0,$t0
mul $t0,$a4,$n0
adcs $acc1,$acc1,$t1
mul $t1,$a5,$n0
adcs $acc2,$acc2,$t2
mul $t2,$a6,$n0
adcs $acc3,$acc3,$t3
mul $t3,$a7,$n0
adcs $acc4,$acc4,$t0
umulh $t0,$a0,$n0
adcs $acc5,$acc5,$t1
umulh $t1,$a1,$n0
adcs $acc6,$acc6,$t2
umulh $t2,$a2,$n0
adcs $acc7,$acc7,$t3
umulh $t3,$a3,$n0
adc $carry,$carry,xzr
str $acc0,[$tp],#8
adds $acc0,$acc1,$t0
umulh $t0,$a4,$n0
adcs $acc1,$acc2,$t1
umulh $t1,$a5,$n0
adcs $acc2,$acc3,$t2
umulh $t2,$a6,$n0
adcs $acc3,$acc4,$t3
umulh $t3,$a7,$n0
ldr $n0,[$rp,$cnt]
adcs $acc4,$acc5,$t0
adcs $acc5,$acc6,$t1
adcs $acc6,$acc7,$t2
adcs $acc7,$carry,$t3
//adc $carry,xzr,xzr // moved above
cbnz $cnt,.Lsqr8x_mul
// note that carry flag is guaranteed
// to be zero at this point
cmp $ap,$ap_end // done yet?
b.eq .Lsqr8x_break
ldp $a0,$a1,[$tp,#8*0]
ldp $a2,$a3,[$tp,#8*2]
ldp $a4,$a5,[$tp,#8*4]
ldp $a6,$a7,[$tp,#8*6]
adds $acc0,$acc0,$a0
ldr $n0,[$rp,#-8*8]
adcs $acc1,$acc1,$a1
ldp $a0,$a1,[$ap,#8*0]
adcs $acc2,$acc2,$a2
adcs $acc3,$acc3,$a3
ldp $a2,$a3,[$ap,#8*2]
adcs $acc4,$acc4,$a4
adcs $acc5,$acc5,$a5
ldp $a4,$a5,[$ap,#8*4]
adcs $acc6,$acc6,$a6
mov $cnt,#-8*8
adcs $acc7,$acc7,$a7
ldp $a6,$a7,[$ap,#8*6]
add $ap,$ap,#8*8
//adc $carry,xzr,xzr // moved above
b .Lsqr8x_mul
.align 4
.Lsqr8x_break:
ldp $a0,$a1,[$rp,#8*0]
add $ap,$rp,#8*8
ldp $a2,$a3,[$rp,#8*2]
sub $t0,$ap_end,$ap // is it last iteration?
ldp $a4,$a5,[$rp,#8*4]
sub $t1,$tp,$t0
ldp $a6,$a7,[$rp,#8*6]
cbz $t0,.Lsqr8x_outer_loop
stp $acc0,$acc1,[$tp,#8*0]
ldp $acc0,$acc1,[$t1,#8*0]
stp $acc2,$acc3,[$tp,#8*2]
ldp $acc2,$acc3,[$t1,#8*2]
stp $acc4,$acc5,[$tp,#8*4]
ldp $acc4,$acc5,[$t1,#8*4]
stp $acc6,$acc7,[$tp,#8*6]
mov $tp,$t1
ldp $acc6,$acc7,[$t1,#8*6]
b .Lsqr8x_outer_loop
.align 4
.Lsqr8x_outer_break:
// Now multiply above result by 2 and add a[n-1]*a[n-1]|...|a[0]*a[0]
ldp $a1,$a3,[$t0,#8*0] // recall that $t0 is &a[0]
ldp $t1,$t2,[sp,#8*1]
ldp $a5,$a7,[$t0,#8*2]
add $ap,$t0,#8*4
ldp $t3,$t0,[sp,#8*3]
stp $acc0,$acc1,[$tp,#8*0]
mul $acc0,$a1,$a1
stp $acc2,$acc3,[$tp,#8*2]
umulh $a1,$a1,$a1
stp $acc4,$acc5,[$tp,#8*4]
mul $a2,$a3,$a3
stp $acc6,$acc7,[$tp,#8*6]
mov $tp,sp
umulh $a3,$a3,$a3
adds $acc1,$a1,$t1,lsl#1
extr $t1,$t2,$t1,#63
sub $cnt,$num,#8*4
.Lsqr4x_shift_n_add:
adcs $acc2,$a2,$t1
extr $t2,$t3,$t2,#63
sub $cnt,$cnt,#8*4
adcs $acc3,$a3,$t2
ldp $t1,$t2,[$tp,#8*5]
mul $a4,$a5,$a5
ldp $a1,$a3,[$ap],#8*2
umulh $a5,$a5,$a5
mul $a6,$a7,$a7
umulh $a7,$a7,$a7
extr $t3,$t0,$t3,#63
stp $acc0,$acc1,[$tp,#8*0]
adcs $acc4,$a4,$t3
extr $t0,$t1,$t0,#63
stp $acc2,$acc3,[$tp,#8*2]
adcs $acc5,$a5,$t0
ldp $t3,$t0,[$tp,#8*7]
extr $t1,$t2,$t1,#63
adcs $acc6,$a6,$t1
extr $t2,$t3,$t2,#63
adcs $acc7,$a7,$t2
ldp $t1,$t2,[$tp,#8*9]
mul $a0,$a1,$a1
ldp $a5,$a7,[$ap],#8*2
umulh $a1,$a1,$a1
mul $a2,$a3,$a3
umulh $a3,$a3,$a3
stp $acc4,$acc5,[$tp,#8*4]
extr $t3,$t0,$t3,#63
stp $acc6,$acc7,[$tp,#8*6]
add $tp,$tp,#8*8
adcs $acc0,$a0,$t3
extr $t0,$t1,$t0,#63
adcs $acc1,$a1,$t0
ldp $t3,$t0,[$tp,#8*3]
extr $t1,$t2,$t1,#63
cbnz $cnt,.Lsqr4x_shift_n_add
___
my ($np,$np_end)=($ap,$ap_end);
$code.=<<___;
ldp $np,$n0,[x29,#104] // pull np and n0
adcs $acc2,$a2,$t1
extr $t2,$t3,$t2,#63
adcs $acc3,$a3,$t2
ldp $t1,$t2,[$tp,#8*5]
mul $a4,$a5,$a5
umulh $a5,$a5,$a5
stp $acc0,$acc1,[$tp,#8*0]
mul $a6,$a7,$a7
umulh $a7,$a7,$a7
stp $acc2,$acc3,[$tp,#8*2]
extr $t3,$t0,$t3,#63
adcs $acc4,$a4,$t3
extr $t0,$t1,$t0,#63
ldp $acc0,$acc1,[sp,#8*0]
adcs $acc5,$a5,$t0
extr $t1,$t2,$t1,#63
ldp $a0,$a1,[$np,#8*0]
adcs $acc6,$a6,$t1
extr $t2,xzr,$t2,#63
ldp $a2,$a3,[$np,#8*2]
adc $acc7,$a7,$t2
ldp $a4,$a5,[$np,#8*4]
// Reduce by 512 bits per iteration
mul $na0,$n0,$acc0 // t[0]*n0
ldp $a6,$a7,[$np,#8*6]
add $np_end,$np,$num
ldp $acc2,$acc3,[sp,#8*2]
stp $acc4,$acc5,[$tp,#8*4]
ldp $acc4,$acc5,[sp,#8*4]
stp $acc6,$acc7,[$tp,#8*6]
ldp $acc6,$acc7,[sp,#8*6]
add $np,$np,#8*8
mov $topmost,xzr // initial top-most carry
mov $tp,sp
mov $cnt,#8
.Lsqr8x_reduction:
// (*) mul $t0,$a0,$na0 // lo(n[0-7])*lo(t[0]*n0)
mul $t1,$a1,$na0
sub $cnt,$cnt,#1
mul $t2,$a2,$na0
str $na0,[$tp],#8 // put aside t[0]*n0 for tail processing
mul $t3,$a3,$na0
// (*) adds xzr,$acc0,$t0
subs xzr,$acc0,#1 // (*)
mul $t0,$a4,$na0
adcs $acc0,$acc1,$t1
mul $t1,$a5,$na0
adcs $acc1,$acc2,$t2
mul $t2,$a6,$na0
adcs $acc2,$acc3,$t3
mul $t3,$a7,$na0
adcs $acc3,$acc4,$t0
umulh $t0,$a0,$na0 // hi(n[0-7])*lo(t[0]*n0)
adcs $acc4,$acc5,$t1
umulh $t1,$a1,$na0
adcs $acc5,$acc6,$t2
umulh $t2,$a2,$na0
adcs $acc6,$acc7,$t3
umulh $t3,$a3,$na0
adc $acc7,xzr,xzr
adds $acc0,$acc0,$t0
umulh $t0,$a4,$na0
adcs $acc1,$acc1,$t1
umulh $t1,$a5,$na0
adcs $acc2,$acc2,$t2
umulh $t2,$a6,$na0
adcs $acc3,$acc3,$t3
umulh $t3,$a7,$na0
mul $na0,$n0,$acc0 // next t[0]*n0
adcs $acc4,$acc4,$t0
adcs $acc5,$acc5,$t1
adcs $acc6,$acc6,$t2
adc $acc7,$acc7,$t3
cbnz $cnt,.Lsqr8x_reduction
ldp $t0,$t1,[$tp,#8*0]
ldp $t2,$t3,[$tp,#8*2]
mov $rp,$tp
sub $cnt,$np_end,$np // done yet?
adds $acc0,$acc0,$t0
adcs $acc1,$acc1,$t1
ldp $t0,$t1,[$tp,#8*4]
adcs $acc2,$acc2,$t2
adcs $acc3,$acc3,$t3
ldp $t2,$t3,[$tp,#8*6]
adcs $acc4,$acc4,$t0
adcs $acc5,$acc5,$t1
adcs $acc6,$acc6,$t2
adcs $acc7,$acc7,$t3
//adc $carry,xzr,xzr // moved below
cbz $cnt,.Lsqr8x8_post_condition
ldr $n0,[$tp,#-8*8]
ldp $a0,$a1,[$np,#8*0]
ldp $a2,$a3,[$np,#8*2]
ldp $a4,$a5,[$np,#8*4]
mov $cnt,#-8*8
ldp $a6,$a7,[$np,#8*6]
add $np,$np,#8*8
.Lsqr8x_tail:
mul $t0,$a0,$n0
adc $carry,xzr,xzr // carry bit, modulo-scheduled
mul $t1,$a1,$n0
add $cnt,$cnt,#8
mul $t2,$a2,$n0
mul $t3,$a3,$n0
adds $acc0,$acc0,$t0
mul $t0,$a4,$n0
adcs $acc1,$acc1,$t1
mul $t1,$a5,$n0
adcs $acc2,$acc2,$t2
mul $t2,$a6,$n0
adcs $acc3,$acc3,$t3
mul $t3,$a7,$n0
adcs $acc4,$acc4,$t0
umulh $t0,$a0,$n0
adcs $acc5,$acc5,$t1
umulh $t1,$a1,$n0
adcs $acc6,$acc6,$t2
umulh $t2,$a2,$n0
adcs $acc7,$acc7,$t3
umulh $t3,$a3,$n0
adc $carry,$carry,xzr
str $acc0,[$tp],#8
adds $acc0,$acc1,$t0
umulh $t0,$a4,$n0
adcs $acc1,$acc2,$t1
umulh $t1,$a5,$n0
adcs $acc2,$acc3,$t2
umulh $t2,$a6,$n0
adcs $acc3,$acc4,$t3
umulh $t3,$a7,$n0
ldr $n0,[$rp,$cnt]
adcs $acc4,$acc5,$t0
adcs $acc5,$acc6,$t1
adcs $acc6,$acc7,$t2
adcs $acc7,$carry,$t3
//adc $carry,xzr,xzr // moved above
cbnz $cnt,.Lsqr8x_tail
// note that carry flag is guaranteed
// to be zero at this point
ldp $a0,$a1,[$tp,#8*0]
sub $cnt,$np_end,$np // done yet?
sub $t2,$np_end,$num // rewinded np
ldp $a2,$a3,[$tp,#8*2]
ldp $a4,$a5,[$tp,#8*4]
ldp $a6,$a7,[$tp,#8*6]
cbz $cnt,.Lsqr8x_tail_break
ldr $n0,[$rp,#-8*8]
adds $acc0,$acc0,$a0
adcs $acc1,$acc1,$a1
ldp $a0,$a1,[$np,#8*0]
adcs $acc2,$acc2,$a2
adcs $acc3,$acc3,$a3
ldp $a2,$a3,[$np,#8*2]
adcs $acc4,$acc4,$a4
adcs $acc5,$acc5,$a5
ldp $a4,$a5,[$np,#8*4]
adcs $acc6,$acc6,$a6
mov $cnt,#-8*8
adcs $acc7,$acc7,$a7
ldp $a6,$a7,[$np,#8*6]
add $np,$np,#8*8
//adc $carry,xzr,xzr // moved above
b .Lsqr8x_tail
.align 4
.Lsqr8x_tail_break:
ldr $n0,[x29,#112] // pull n0
add $cnt,$tp,#8*8 // end of current t[num] window
subs xzr,$topmost,#1 // "move" top-most carry to carry bit
adcs $t0,$acc0,$a0
adcs $t1,$acc1,$a1
ldp $acc0,$acc1,[$rp,#8*0]
adcs $acc2,$acc2,$a2
ldp $a0,$a1,[$t2,#8*0] // recall that $t2 is &n[0]
adcs $acc3,$acc3,$a3
ldp $a2,$a3,[$t2,#8*2]
adcs $acc4,$acc4,$a4
adcs $acc5,$acc5,$a5
ldp $a4,$a5,[$t2,#8*4]
adcs $acc6,$acc6,$a6
adcs $acc7,$acc7,$a7
ldp $a6,$a7,[$t2,#8*6]
add $np,$t2,#8*8
adc $topmost,xzr,xzr // top-most carry
mul $na0,$n0,$acc0
stp $t0,$t1,[$tp,#8*0]
stp $acc2,$acc3,[$tp,#8*2]
ldp $acc2,$acc3,[$rp,#8*2]
stp $acc4,$acc5,[$tp,#8*4]
ldp $acc4,$acc5,[$rp,#8*4]
cmp $cnt,x29 // did we hit the bottom?
stp $acc6,$acc7,[$tp,#8*6]
mov $tp,$rp // slide the window
ldp $acc6,$acc7,[$rp,#8*6]
mov $cnt,#8
b.ne .Lsqr8x_reduction
// Final step. We see if result is larger than modulus, and
// if it is, subtract the modulus. But comparison implies
// subtraction. So we subtract modulus, see if it borrowed,
// and conditionally copy original value.
ldr $rp,[x29,#96] // pull rp
add $tp,$tp,#8*8
subs $t0,$acc0,$a0
sbcs $t1,$acc1,$a1
sub $cnt,$num,#8*8
mov $ap_end,$rp // $rp copy
.Lsqr8x_sub:
sbcs $t2,$acc2,$a2
ldp $a0,$a1,[$np,#8*0]
sbcs $t3,$acc3,$a3
stp $t0,$t1,[$rp,#8*0]
sbcs $t0,$acc4,$a4
ldp $a2,$a3,[$np,#8*2]
sbcs $t1,$acc5,$a5
stp $t2,$t3,[$rp,#8*2]
sbcs $t2,$acc6,$a6
ldp $a4,$a5,[$np,#8*4]
sbcs $t3,$acc7,$a7
ldp $a6,$a7,[$np,#8*6]
add $np,$np,#8*8
ldp $acc0,$acc1,[$tp,#8*0]
sub $cnt,$cnt,#8*8
ldp $acc2,$acc3,[$tp,#8*2]
ldp $acc4,$acc5,[$tp,#8*4]
ldp $acc6,$acc7,[$tp,#8*6]
add $tp,$tp,#8*8
stp $t0,$t1,[$rp,#8*4]
sbcs $t0,$acc0,$a0
stp $t2,$t3,[$rp,#8*6]
add $rp,$rp,#8*8
sbcs $t1,$acc1,$a1
cbnz $cnt,.Lsqr8x_sub
sbcs $t2,$acc2,$a2
mov $tp,sp
add $ap,sp,$num
ldp $a0,$a1,[$ap_end,#8*0]
sbcs $t3,$acc3,$a3
stp $t0,$t1,[$rp,#8*0]
sbcs $t0,$acc4,$a4
ldp $a2,$a3,[$ap_end,#8*2]
sbcs $t1,$acc5,$a5
stp $t2,$t3,[$rp,#8*2]
sbcs $t2,$acc6,$a6
ldp $acc0,$acc1,[$ap,#8*0]
sbcs $t3,$acc7,$a7
ldp $acc2,$acc3,[$ap,#8*2]
sbcs xzr,$topmost,xzr // did it borrow?
ldr x30,[x29,#8] // pull return address
stp $t0,$t1,[$rp,#8*4]
stp $t2,$t3,[$rp,#8*6]
sub $cnt,$num,#8*4
.Lsqr4x_cond_copy:
sub $cnt,$cnt,#8*4
csel $t0,$acc0,$a0,lo
stp xzr,xzr,[$tp,#8*0]
csel $t1,$acc1,$a1,lo
ldp $a0,$a1,[$ap_end,#8*4]
ldp $acc0,$acc1,[$ap,#8*4]
csel $t2,$acc2,$a2,lo
stp xzr,xzr,[$tp,#8*2]
add $tp,$tp,#8*4
csel $t3,$acc3,$a3,lo
ldp $a2,$a3,[$ap_end,#8*6]
ldp $acc2,$acc3,[$ap,#8*6]
add $ap,$ap,#8*4
stp $t0,$t1,[$ap_end,#8*0]
stp $t2,$t3,[$ap_end,#8*2]
add $ap_end,$ap_end,#8*4
stp xzr,xzr,[$ap,#8*0]
stp xzr,xzr,[$ap,#8*2]
cbnz $cnt,.Lsqr4x_cond_copy
csel $t0,$acc0,$a0,lo
stp xzr,xzr,[$tp,#8*0]
csel $t1,$acc1,$a1,lo
stp xzr,xzr,[$tp,#8*2]
csel $t2,$acc2,$a2,lo
csel $t3,$acc3,$a3,lo
stp $t0,$t1,[$ap_end,#8*0]
stp $t2,$t3,[$ap_end,#8*2]
b .Lsqr8x_done
.align 4
.Lsqr8x8_post_condition:
adc $carry,xzr,xzr
ldr x30,[x29,#8] // pull return address
// $acc0-7,$carry hold result, $a0-7 hold modulus
subs $a0,$acc0,$a0
ldr $ap,[x29,#96] // pull rp
sbcs $a1,$acc1,$a1
stp xzr,xzr,[sp,#8*0]
sbcs $a2,$acc2,$a2
stp xzr,xzr,[sp,#8*2]
sbcs $a3,$acc3,$a3
stp xzr,xzr,[sp,#8*4]
sbcs $a4,$acc4,$a4
stp xzr,xzr,[sp,#8*6]
sbcs $a5,$acc5,$a5
stp xzr,xzr,[sp,#8*8]
sbcs $a6,$acc6,$a6
stp xzr,xzr,[sp,#8*10]
sbcs $a7,$acc7,$a7
stp xzr,xzr,[sp,#8*12]
sbcs $carry,$carry,xzr // did it borrow?
stp xzr,xzr,[sp,#8*14]
// $a0-7 hold result-modulus
csel $a0,$acc0,$a0,lo
csel $a1,$acc1,$a1,lo
csel $a2,$acc2,$a2,lo
csel $a3,$acc3,$a3,lo
stp $a0,$a1,[$ap,#8*0]
csel $a4,$acc4,$a4,lo
csel $a5,$acc5,$a5,lo
stp $a2,$a3,[$ap,#8*2]
csel $a6,$acc6,$a6,lo
csel $a7,$acc7,$a7,lo
stp $a4,$a5,[$ap,#8*4]
stp $a6,$a7,[$ap,#8*6]
.Lsqr8x_done:
ldp x19,x20,[x29,#16]
mov sp,x29
ldp x21,x22,[x29,#32]
mov x0,#1
ldp x23,x24,[x29,#48]
ldp x25,x26,[x29,#64]
ldp x27,x28,[x29,#80]
ldr x29,[sp],#128
ret
.size __bn_sqr8x_mont,.-__bn_sqr8x_mont
___
}
{
########################################################################
# Even though this might look as ARMv8 adaptation of mulx4x_mont from
# x86_64-mont5 module, it's different in sense that it performs
# reduction 256 bits at a time.
my ($a0,$a1,$a2,$a3,
$t0,$t1,$t2,$t3,
$m0,$m1,$m2,$m3,
$acc0,$acc1,$acc2,$acc3,$acc4,
$bi,$mi,$tp,$ap_end,$cnt) = map("x$_",(6..17,19..28));
my $bp_end=$rp;
my ($carry,$topmost) = ($rp,"x30");
$code.=<<___;
.type __bn_mul4x_mont,%function
.align 5
__bn_mul4x_mont:
stp x29,x30,[sp,#-128]!
add x29,sp,#0
stp x19,x20,[sp,#16]
stp x21,x22,[sp,#32]
stp x23,x24,[sp,#48]
stp x25,x26,[sp,#64]
stp x27,x28,[sp,#80]
sub $tp,sp,$num,lsl#3
lsl $num,$num,#3
ldr $n0,[$n0] // *n0
sub sp,$tp,#8*4 // alloca
add $t0,$bp,$num
add $ap_end,$ap,$num
stp $rp,$t0,[x29,#96] // offload rp and &b[num]
ldr $bi,[$bp,#8*0] // b[0]
ldp $a0,$a1,[$ap,#8*0] // a[0..3]
ldp $a2,$a3,[$ap,#8*2]
add $ap,$ap,#8*4
mov $acc0,xzr
mov $acc1,xzr
mov $acc2,xzr
mov $acc3,xzr
ldp $m0,$m1,[$np,#8*0] // n[0..3]
ldp $m2,$m3,[$np,#8*2]
adds $np,$np,#8*4 // clear carry bit
mov $carry,xzr
mov $cnt,#0
mov $tp,sp
.Loop_mul4x_1st_reduction:
mul $t0,$a0,$bi // lo(a[0..3]*b[0])
adc $carry,$carry,xzr // modulo-scheduled
mul $t1,$a1,$bi
add $cnt,$cnt,#8
mul $t2,$a2,$bi
and $cnt,$cnt,#31
mul $t3,$a3,$bi
adds $acc0,$acc0,$t0
umulh $t0,$a0,$bi // hi(a[0..3]*b[0])
adcs $acc1,$acc1,$t1
mul $mi,$acc0,$n0 // t[0]*n0
adcs $acc2,$acc2,$t2
umulh $t1,$a1,$bi
adcs $acc3,$acc3,$t3
umulh $t2,$a2,$bi
adc $acc4,xzr,xzr
umulh $t3,$a3,$bi
ldr $bi,[$bp,$cnt] // next b[i] (or b[0])
adds $acc1,$acc1,$t0
// (*) mul $t0,$m0,$mi // lo(n[0..3]*t[0]*n0)
str $mi,[$tp],#8 // put aside t[0]*n0 for tail processing
adcs $acc2,$acc2,$t1
mul $t1,$m1,$mi
adcs $acc3,$acc3,$t2
mul $t2,$m2,$mi
adc $acc4,$acc4,$t3 // can't overflow
mul $t3,$m3,$mi
// (*) adds xzr,$acc0,$t0
subs xzr,$acc0,#1 // (*)
umulh $t0,$m0,$mi // hi(n[0..3]*t[0]*n0)
adcs $acc0,$acc1,$t1
umulh $t1,$m1,$mi
adcs $acc1,$acc2,$t2
umulh $t2,$m2,$mi
adcs $acc2,$acc3,$t3
umulh $t3,$m3,$mi
adcs $acc3,$acc4,$carry
adc $carry,xzr,xzr
adds $acc0,$acc0,$t0
sub $t0,$ap_end,$ap
adcs $acc1,$acc1,$t1
adcs $acc2,$acc2,$t2
adcs $acc3,$acc3,$t3
//adc $carry,$carry,xzr
cbnz $cnt,.Loop_mul4x_1st_reduction
cbz $t0,.Lmul4x4_post_condition
ldp $a0,$a1,[$ap,#8*0] // a[4..7]
ldp $a2,$a3,[$ap,#8*2]
add $ap,$ap,#8*4
ldr $mi,[sp] // a[0]*n0
ldp $m0,$m1,[$np,#8*0] // n[4..7]
ldp $m2,$m3,[$np,#8*2]
add $np,$np,#8*4
.Loop_mul4x_1st_tail:
mul $t0,$a0,$bi // lo(a[4..7]*b[i])
adc $carry,$carry,xzr // modulo-scheduled
mul $t1,$a1,$bi
add $cnt,$cnt,#8
mul $t2,$a2,$bi
and $cnt,$cnt,#31
mul $t3,$a3,$bi
adds $acc0,$acc0,$t0
umulh $t0,$a0,$bi // hi(a[4..7]*b[i])
adcs $acc1,$acc1,$t1
umulh $t1,$a1,$bi
adcs $acc2,$acc2,$t2
umulh $t2,$a2,$bi
adcs $acc3,$acc3,$t3
umulh $t3,$a3,$bi
adc $acc4,xzr,xzr
ldr $bi,[$bp,$cnt] // next b[i] (or b[0])
adds $acc1,$acc1,$t0
mul $t0,$m0,$mi // lo(n[4..7]*a[0]*n0)
adcs $acc2,$acc2,$t1
mul $t1,$m1,$mi
adcs $acc3,$acc3,$t2
mul $t2,$m2,$mi
adc $acc4,$acc4,$t3 // can't overflow
mul $t3,$m3,$mi
adds $acc0,$acc0,$t0
umulh $t0,$m0,$mi // hi(n[4..7]*a[0]*n0)
adcs $acc1,$acc1,$t1
umulh $t1,$m1,$mi
adcs $acc2,$acc2,$t2
umulh $t2,$m2,$mi
adcs $acc3,$acc3,$t3
adcs $acc4,$acc4,$carry
umulh $t3,$m3,$mi
adc $carry,xzr,xzr
ldr $mi,[sp,$cnt] // next t[0]*n0
str $acc0,[$tp],#8 // result!!!
adds $acc0,$acc1,$t0
sub $t0,$ap_end,$ap // done yet?
adcs $acc1,$acc2,$t1
adcs $acc2,$acc3,$t2
adcs $acc3,$acc4,$t3
//adc $carry,$carry,xzr
cbnz $cnt,.Loop_mul4x_1st_tail
sub $t1,$ap_end,$num // rewinded $ap
cbz $t0,.Lmul4x_proceed
ldp $a0,$a1,[$ap,#8*0]
ldp $a2,$a3,[$ap,#8*2]
add $ap,$ap,#8*4
ldp $m0,$m1,[$np,#8*0]
ldp $m2,$m3,[$np,#8*2]
add $np,$np,#8*4
b .Loop_mul4x_1st_tail
.align 5
.Lmul4x_proceed:
ldr $bi,[$bp,#8*4]! // *++b
adc $topmost,$carry,xzr
ldp $a0,$a1,[$t1,#8*0] // a[0..3]
sub $np,$np,$num // rewind np
ldp $a2,$a3,[$t1,#8*2]
add $ap,$t1,#8*4
stp $acc0,$acc1,[$tp,#8*0] // result!!!
ldp $acc0,$acc1,[sp,#8*4] // t[0..3]
stp $acc2,$acc3,[$tp,#8*2] // result!!!
ldp $acc2,$acc3,[sp,#8*6]
ldp $m0,$m1,[$np,#8*0] // n[0..3]
mov $tp,sp
ldp $m2,$m3,[$np,#8*2]
adds $np,$np,#8*4 // clear carry bit
mov $carry,xzr
.align 4
.Loop_mul4x_reduction:
mul $t0,$a0,$bi // lo(a[0..3]*b[4])
adc $carry,$carry,xzr // modulo-scheduled
mul $t1,$a1,$bi
add $cnt,$cnt,#8
mul $t2,$a2,$bi
and $cnt,$cnt,#31
mul $t3,$a3,$bi
adds $acc0,$acc0,$t0
umulh $t0,$a0,$bi // hi(a[0..3]*b[4])
adcs $acc1,$acc1,$t1
mul $mi,$acc0,$n0 // t[0]*n0
adcs $acc2,$acc2,$t2
umulh $t1,$a1,$bi
adcs $acc3,$acc3,$t3
umulh $t2,$a2,$bi
adc $acc4,xzr,xzr
umulh $t3,$a3,$bi
ldr $bi,[$bp,$cnt] // next b[i]
adds $acc1,$acc1,$t0
// (*) mul $t0,$m0,$mi
str $mi,[$tp],#8 // put aside t[0]*n0 for tail processing
adcs $acc2,$acc2,$t1
mul $t1,$m1,$mi // lo(n[0..3]*t[0]*n0
adcs $acc3,$acc3,$t2
mul $t2,$m2,$mi
adc $acc4,$acc4,$t3 // can't overflow
mul $t3,$m3,$mi
// (*) adds xzr,$acc0,$t0
subs xzr,$acc0,#1 // (*)
umulh $t0,$m0,$mi // hi(n[0..3]*t[0]*n0
adcs $acc0,$acc1,$t1
umulh $t1,$m1,$mi
adcs $acc1,$acc2,$t2
umulh $t2,$m2,$mi
adcs $acc2,$acc3,$t3
umulh $t3,$m3,$mi
adcs $acc3,$acc4,$carry
adc $carry,xzr,xzr
adds $acc0,$acc0,$t0
adcs $acc1,$acc1,$t1
adcs $acc2,$acc2,$t2
adcs $acc3,$acc3,$t3
//adc $carry,$carry,xzr
cbnz $cnt,.Loop_mul4x_reduction
adc $carry,$carry,xzr
ldp $t0,$t1,[$tp,#8*4] // t[4..7]
ldp $t2,$t3,[$tp,#8*6]
ldp $a0,$a1,[$ap,#8*0] // a[4..7]
ldp $a2,$a3,[$ap,#8*2]
add $ap,$ap,#8*4
adds $acc0,$acc0,$t0
adcs $acc1,$acc1,$t1
adcs $acc2,$acc2,$t2
adcs $acc3,$acc3,$t3
//adc $carry,$carry,xzr
ldr $mi,[sp] // t[0]*n0
ldp $m0,$m1,[$np,#8*0] // n[4..7]
ldp $m2,$m3,[$np,#8*2]
add $np,$np,#8*4
.align 4
.Loop_mul4x_tail:
mul $t0,$a0,$bi // lo(a[4..7]*b[4])
adc $carry,$carry,xzr // modulo-scheduled
mul $t1,$a1,$bi
add $cnt,$cnt,#8
mul $t2,$a2,$bi
and $cnt,$cnt,#31
mul $t3,$a3,$bi
adds $acc0,$acc0,$t0
umulh $t0,$a0,$bi // hi(a[4..7]*b[4])
adcs $acc1,$acc1,$t1
umulh $t1,$a1,$bi
adcs $acc2,$acc2,$t2
umulh $t2,$a2,$bi
adcs $acc3,$acc3,$t3
umulh $t3,$a3,$bi
adc $acc4,xzr,xzr
ldr $bi,[$bp,$cnt] // next b[i]
adds $acc1,$acc1,$t0
mul $t0,$m0,$mi // lo(n[4..7]*t[0]*n0)
adcs $acc2,$acc2,$t1
mul $t1,$m1,$mi
adcs $acc3,$acc3,$t2
mul $t2,$m2,$mi
adc $acc4,$acc4,$t3 // can't overflow
mul $t3,$m3,$mi
adds $acc0,$acc0,$t0
umulh $t0,$m0,$mi // hi(n[4..7]*t[0]*n0)
adcs $acc1,$acc1,$t1
umulh $t1,$m1,$mi
adcs $acc2,$acc2,$t2
umulh $t2,$m2,$mi
adcs $acc3,$acc3,$t3
umulh $t3,$m3,$mi
adcs $acc4,$acc4,$carry
ldr $mi,[sp,$cnt] // next a[0]*n0
adc $carry,xzr,xzr
str $acc0,[$tp],#8 // result!!!
adds $acc0,$acc1,$t0
sub $t0,$ap_end,$ap // done yet?
adcs $acc1,$acc2,$t1
adcs $acc2,$acc3,$t2
adcs $acc3,$acc4,$t3
//adc $carry,$carry,xzr
cbnz $cnt,.Loop_mul4x_tail
sub $t1,$np,$num // rewinded np?
adc $carry,$carry,xzr
cbz $t0,.Loop_mul4x_break
ldp $t0,$t1,[$tp,#8*4]
ldp $t2,$t3,[$tp,#8*6]
ldp $a0,$a1,[$ap,#8*0]
ldp $a2,$a3,[$ap,#8*2]
add $ap,$ap,#8*4
adds $acc0,$acc0,$t0
adcs $acc1,$acc1,$t1
adcs $acc2,$acc2,$t2
adcs $acc3,$acc3,$t3
//adc $carry,$carry,xzr
ldp $m0,$m1,[$np,#8*0]
ldp $m2,$m3,[$np,#8*2]
add $np,$np,#8*4
b .Loop_mul4x_tail
.align 4
.Loop_mul4x_break:
ldp $t2,$t3,[x29,#96] // pull rp and &b[num]
adds $acc0,$acc0,$topmost
add $bp,$bp,#8*4 // bp++
adcs $acc1,$acc1,xzr
sub $ap,$ap,$num // rewind ap
adcs $acc2,$acc2,xzr
stp $acc0,$acc1,[$tp,#8*0] // result!!!
adcs $acc3,$acc3,xzr
ldp $acc0,$acc1,[sp,#8*4] // t[0..3]
adc $topmost,$carry,xzr
stp $acc2,$acc3,[$tp,#8*2] // result!!!
cmp $bp,$t3 // done yet?
ldp $acc2,$acc3,[sp,#8*6]
ldp $m0,$m1,[$t1,#8*0] // n[0..3]
ldp $m2,$m3,[$t1,#8*2]
add $np,$t1,#8*4
b.eq .Lmul4x_post
ldr $bi,[$bp]
ldp $a0,$a1,[$ap,#8*0] // a[0..3]
ldp $a2,$a3,[$ap,#8*2]
adds $ap,$ap,#8*4 // clear carry bit
mov $carry,xzr
mov $tp,sp
b .Loop_mul4x_reduction
.align 4
.Lmul4x_post:
// Final step. We see if result is larger than modulus, and
// if it is, subtract the modulus. But comparison implies
// subtraction. So we subtract modulus, see if it borrowed,
// and conditionally copy original value.
mov $rp,$t2
mov $ap_end,$t2 // $rp copy
subs $t0,$acc0,$m0
add $tp,sp,#8*8
sbcs $t1,$acc1,$m1
sub $cnt,$num,#8*4
.Lmul4x_sub:
sbcs $t2,$acc2,$m2
ldp $m0,$m1,[$np,#8*0]
sub $cnt,$cnt,#8*4
ldp $acc0,$acc1,[$tp,#8*0]
sbcs $t3,$acc3,$m3
ldp $m2,$m3,[$np,#8*2]
add $np,$np,#8*4
ldp $acc2,$acc3,[$tp,#8*2]
add $tp,$tp,#8*4
stp $t0,$t1,[$rp,#8*0]
sbcs $t0,$acc0,$m0
stp $t2,$t3,[$rp,#8*2]
add $rp,$rp,#8*4
sbcs $t1,$acc1,$m1
cbnz $cnt,.Lmul4x_sub
sbcs $t2,$acc2,$m2
mov $tp,sp
add $ap,sp,#8*4
ldp $a0,$a1,[$ap_end,#8*0]
sbcs $t3,$acc3,$m3
stp $t0,$t1,[$rp,#8*0]
ldp $a2,$a3,[$ap_end,#8*2]
stp $t2,$t3,[$rp,#8*2]
ldp $acc0,$acc1,[$ap,#8*0]
ldp $acc2,$acc3,[$ap,#8*2]
sbcs xzr,$topmost,xzr // did it borrow?
ldr x30,[x29,#8] // pull return address
sub $cnt,$num,#8*4
.Lmul4x_cond_copy:
sub $cnt,$cnt,#8*4
csel $t0,$acc0,$a0,lo
stp xzr,xzr,[$tp,#8*0]
csel $t1,$acc1,$a1,lo
ldp $a0,$a1,[$ap_end,#8*4]
ldp $acc0,$acc1,[$ap,#8*4]
csel $t2,$acc2,$a2,lo
stp xzr,xzr,[$tp,#8*2]
add $tp,$tp,#8*4
csel $t3,$acc3,$a3,lo
ldp $a2,$a3,[$ap_end,#8*6]
ldp $acc2,$acc3,[$ap,#8*6]
add $ap,$ap,#8*4
stp $t0,$t1,[$ap_end,#8*0]
stp $t2,$t3,[$ap_end,#8*2]
add $ap_end,$ap_end,#8*4
cbnz $cnt,.Lmul4x_cond_copy
csel $t0,$acc0,$a0,lo
stp xzr,xzr,[$tp,#8*0]
csel $t1,$acc1,$a1,lo
stp xzr,xzr,[$tp,#8*2]
csel $t2,$acc2,$a2,lo
stp xzr,xzr,[$tp,#8*3]
csel $t3,$acc3,$a3,lo
stp xzr,xzr,[$tp,#8*4]
stp $t0,$t1,[$ap_end,#8*0]
stp $t2,$t3,[$ap_end,#8*2]
b .Lmul4x_done
.align 4
.Lmul4x4_post_condition:
adc $carry,$carry,xzr
ldr $ap,[x29,#96] // pull rp
// $acc0-3,$carry hold result, $m0-7 hold modulus
subs $a0,$acc0,$m0
ldr x30,[x29,#8] // pull return address
sbcs $a1,$acc1,$m1
stp xzr,xzr,[sp,#8*0]
sbcs $a2,$acc2,$m2
stp xzr,xzr,[sp,#8*2]
sbcs $a3,$acc3,$m3
stp xzr,xzr,[sp,#8*4]
sbcs xzr,$carry,xzr // did it borrow?
stp xzr,xzr,[sp,#8*6]
// $a0-3 hold result-modulus
csel $a0,$acc0,$a0,lo
csel $a1,$acc1,$a1,lo
csel $a2,$acc2,$a2,lo
csel $a3,$acc3,$a3,lo
stp $a0,$a1,[$ap,#8*0]
stp $a2,$a3,[$ap,#8*2]
.Lmul4x_done:
ldp x19,x20,[x29,#16]
mov sp,x29
ldp x21,x22,[x29,#32]
mov x0,#1
ldp x23,x24,[x29,#48]
ldp x25,x26,[x29,#64]
ldp x27,x28,[x29,#80]
ldr x29,[sp],#128
ret
.size __bn_mul4x_mont,.-__bn_mul4x_mont
___
}
$code.=<<___;
.asciz "Montgomery Multiplication for ARMv8, CRYPTOGAMS by <appro\@openssl.org>"
.align 4
___
print $code;
close STDOUT;
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