openssl/crypto/ec/asm/x25519-x86_64.pl
Andy Polyakov e72bf96718 ec/asm/x25519-x86_64.pl: remove redundant carry chain.
Why is it redundant? We're looking at carry from addition of small,
11-bit number to 256-bit one. And carry would mean only one thing,
resulting first limb being small number and remaing ones - zeros.
Hence adding 38 to first limb can't carry.

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/5476)
2018-03-01 13:59:28 +01:00

809 lines
17 KiB
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Executable file

#!/usr/bin/env perl
# Copyright 2018 The OpenSSL Project Authors. All Rights Reserved.
#
# Licensed under the OpenSSL license (the "License"). You may not use
# this file except in compliance with the License. You can obtain a copy
# in the file LICENSE in the source distribution or at
# https://www.openssl.org/source/license.html
#
# ====================================================================
# 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/.
# ====================================================================
#
# X25519 lower-level primitives for x86_86.
#
# February 2018.
#
# This module implements radix 2^51 multiplication and squaring, and
# radix 2^64 multiplication, squaring, addition, subtraction and final
# reduction. Latter radix is used on ADCX/ADOX-capable processors such
# as Broadwell. On related note one should mention that there are
# vector implementations that provide significantly better performance
# on some processors(*), but they are large and overly complex. Which
# in combination with them being effectively processor-specific makes
# the undertaking hard to justify. The goal for this implementation
# is rather versatility and simplicity [and ultimately formal
# verification].
#
# (*) For example sandy2x should provide ~30% improvement on Sandy
# Bridge, but only nominal ~5% on Haswell [and big loss on
# Broadwell and successors].
#
######################################################################
# Improvement coefficients:
#
# amd64-51(*) gcc-5.x(**)
#
# P4 +22% +40%
# Sandy Bridge -3% +11%
# Haswell -1% +13%
# Broadwell(***) +30% +35%
# Skylake(***) +33% +47%
# Silvermont +20% +26%
# Goldmont +40% +50%
# Bulldozer +20% +9%
# Ryzen(***) +43% +40%
# VIA +170% +120%
#
# (*) amd64-51 is popular assembly implementation with 2^51 radix,
# only multiplication and squaring subroutines were linked
# for comparison, but not complete ladder step; gain on most
# processors is because this module refrains from shld, and
# minor regression on others is because this does result in
# higher instruction count;
# (**) compiler is free to inline functions, in assembly one would
# need to implement ladder step to do that, and it will improve
# performance by several percent;
# (***) ADCX/ADOX result for 2^64 radix, there is no corresponding
# C implementation, so that comparison is always against
# 2^51 radix;
$flavour = shift;
$output = shift;
if ($flavour =~ /\./) { $output = $flavour; undef $flavour; }
$win64=0; $win64=1 if ($flavour =~ /[nm]asm|mingw64/ || $output =~ /\.asm$/);
$0 =~ m/(.*[\/\\])[^\/\\]+$/; $dir=$1;
( $xlate="${dir}x86_64-xlate.pl" and -f $xlate ) or
( $xlate="${dir}../../perlasm/x86_64-xlate.pl" and -f $xlate) or
die "can't locate x86_64-xlate.pl";
open OUT,"| \"$^X\" \"$xlate\" $flavour \"$output\"";
*STDOUT=*OUT;
if (`$ENV{CC} -Wa,-v -c -o /dev/null -x assembler /dev/null 2>&1`
=~ /GNU assembler version ([2-9]\.[0-9]+)/) {
$addx = ($1>=2.23);
}
if (!$addx && $win64 && ($flavour =~ /nasm/ || $ENV{ASM} =~ /nasm/) &&
`nasm -v 2>&1` =~ /NASM version ([2-9]\.[0-9]+)/) {
$addx = ($1>=2.10);
}
if (!$addx && $win64 && ($flavour =~ /masm/ || $ENV{ASM} =~ /ml64/) &&
`ml64 2>&1` =~ /Version ([0-9]+)\./) {
$addx = ($1>=12);
}
if (!$addx && `$ENV{CC} -v 2>&1` =~ /((?:^clang|LLVM) version|.*based on LLVM) ([3-9])\.([0-9]+)/) {
my $ver = $2 + $3/100.0; # 3.1->3.01, 3.10->3.10
$addx = ($ver>=3.03);
}
$code.=<<___;
.text
.globl x25519_fe51_mul
.type x25519_fe51_mul,\@function,3
.align 32
x25519_fe51_mul:
push %rbp
push %rbx
push %r12
push %r13
push %r14
push %r15
lea -8*5(%rsp),%rsp
mov 8*0(%rsi),%rax # f[0]
mov 8*0(%rdx),%r11 # load g[0-4]
mov 8*1(%rdx),%r12
mov 8*2(%rdx),%r13
mov 8*3(%rdx),%rbp
mov 8*4(%rdx),%r14
mov %rdi,8*4(%rsp) # offload 1st argument
mov %rax,%rdi
mulq %r11 # f[0]*g[0]
mov %r11,8*0(%rsp) # offload g[0]
mov %rax,%rbx # %rbx:%rcx = h0
mov %rdi,%rax
mov %rdx,%rcx
mulq %r12 # f[0]*g[1]
mov %r12,8*1(%rsp) # offload g[1]
mov %rax,%r8 # %r8:%r9 = h1
mov %rdi,%rax
lea (%r14,%r14,8),%r15
mov %rdx,%r9
mulq %r13 # f[0]*g[2]
mov %r13,8*2(%rsp) # offload g[2]
mov %rax,%r10 # %r10:%r11 = h2
mov %rdi,%rax
lea (%r14,%r15,2),%rdi # g[4]*19
mov %rdx,%r11
mulq %rbp # f[0]*g[3]
mov %rax,%r12 # %r12:%r13 = h3
mov 8*0(%rsi),%rax # f[0]
mov %rdx,%r13
mulq %r14 # f[0]*g[4]
mov %rax,%r14 # %r14:%r15 = h4
mov 8*1(%rsi),%rax # f[1]
mov %rdx,%r15
mulq %rdi # f[1]*g[4]*19
add %rax,%rbx
mov 8*2(%rsi),%rax # f[2]
adc %rdx,%rcx
mulq %rdi # f[2]*g[4]*19
add %rax,%r8
mov 8*3(%rsi),%rax # f[3]
adc %rdx,%r9
mulq %rdi # f[3]*g[4]*19
add %rax,%r10
mov 8*4(%rsi),%rax # f[4]
adc %rdx,%r11
mulq %rdi # f[4]*g[4]*19
imulq \$19,%rbp,%rdi # g[3]*19
add %rax,%r12
mov 8*1(%rsi),%rax # f[1]
adc %rdx,%r13
mulq %rbp # f[1]*g[3]
mov 8*2(%rsp),%rbp # g[2]
add %rax,%r14
mov 8*2(%rsi),%rax # f[2]
adc %rdx,%r15
mulq %rdi # f[2]*g[3]*19
add %rax,%rbx
mov 8*3(%rsi),%rax # f[3]
adc %rdx,%rcx
mulq %rdi # f[3]*g[3]*19
add %rax,%r8
mov 8*4(%rsi),%rax # f[4]
adc %rdx,%r9
mulq %rdi # f[4]*g[3]*19
imulq \$19,%rbp,%rdi # g[2]*19
add %rax,%r10
mov 8*1(%rsi),%rax # f[1]
adc %rdx,%r11
mulq %rbp # f[1]*g[2]
add %rax,%r12
mov 8*2(%rsi),%rax # f[2]
adc %rdx,%r13
mulq %rbp # f[2]*g[2]
mov 8*1(%rsp),%rbp # g[1]
add %rax,%r14
mov 8*3(%rsi),%rax # f[3]
adc %rdx,%r15
mulq %rdi # f[3]*g[2]*19
add %rax,%rbx
mov 8*4(%rsi),%rax # f[3]
adc %rdx,%rcx
mulq %rdi # f[4]*g[2]*19
add %rax,%r8
mov 8*1(%rsi),%rax # f[1]
adc %rdx,%r9
mulq %rbp # f[1]*g[1]
imulq \$19,%rbp,%rdi
add %rax,%r10
mov 8*2(%rsi),%rax # f[2]
adc %rdx,%r11
mulq %rbp # f[2]*g[1]
add %rax,%r12
mov 8*3(%rsi),%rax # f[3]
adc %rdx,%r13
mulq %rbp # f[3]*g[1]
mov 8*0(%rsp),%rbp # g[0]
add %rax,%r14
mov 8*4(%rsi),%rax # f[4]
adc %rdx,%r15
mulq %rdi # f[4]*g[1]*19
add %rax,%rbx
mov 8*1(%rsi),%rax # f[1]
adc %rdx,%rcx
mul %rbp # f[1]*g[0]
add %rax,%r8
mov 8*2(%rsi),%rax # f[2]
adc %rdx,%r9
mul %rbp # f[2]*g[0]
add %rax,%r10
mov 8*3(%rsi),%rax # f[3]
adc %rdx,%r11
mul %rbp # f[3]*g[0]
add %rax,%r12
mov 8*4(%rsi),%rax # f[4]
adc %rdx,%r13
mulq %rbp # f[4]*g[0]
add %rax,%r14
adc %rdx,%r15
mov 8*4(%rsp),%rdi # restore 1st argument
jmp .Lreduce51
.size x25519_fe51_mul,.-x25519_fe51_mul
.globl x25519_fe51_sqr
.type x25519_fe51_sqr,\@function,2
.align 32
x25519_fe51_sqr:
push %rbp
push %rbx
push %r12
push %r13
push %r14
push %r15
lea -8*5(%rsp),%rsp
mov 8*0(%rsi),%rax # g[0]
mov 8*2(%rsi),%r15 # g[2]
mov 8*4(%rsi),%rbp # g[4]
mov %rdi,8*4(%rsp) # offload 1st argument
lea (%rax,%rax),%r14
mulq %rax # g[0]*g[0]
mov %rax,%rbx
mov 8*1(%rsi),%rax # g[1]
mov %rdx,%rcx
mulq %r14 # 2*g[0]*g[1]
mov %rax,%r8
mov %r15,%rax
mov %r15,8*0(%rsp) # offload g[2]
mov %rdx,%r9
mulq %r14 # 2*g[0]*g[2]
mov %rax,%r10
mov 8*3(%rsi),%rax
mov %rdx,%r11
imulq \$19,%rbp,%rdi # g[4]*19
mulq %r14 # 2*g[0]*g[3]
mov %rax,%r12
mov %rbp,%rax
mov %rdx,%r13
mulq %r14 # 2*g[0]*g[4]
mov %rax,%r14
mov %rbp,%rax
mov %rdx,%r15
mulq %rdi # g[4]*g[4]*19
add %rax,%r12
mov 8*1(%rsi),%rax # g[1]
adc %rdx,%r13
mov 8*3(%rsi),%rsi # g[3]
lea (%rax,%rax),%rbp
mulq %rax # g[1]*g[1]
add %rax,%r10
mov 8*0(%rsp),%rax # g[2]
adc %rdx,%r11
mulq %rbp # 2*g[1]*g[2]
add %rax,%r12
mov %rbp,%rax
adc %rdx,%r13
mulq %rsi # 2*g[1]*g[3]
add %rax,%r14
mov %rbp,%rax
adc %rdx,%r15
imulq \$19,%rsi,%rbp # g[3]*19
mulq %rdi # 2*g[1]*g[4]*19
add %rax,%rbx
lea (%rsi,%rsi),%rax
adc %rdx,%rcx
mulq %rdi # 2*g[3]*g[4]*19
add %rax,%r10
mov %rsi,%rax
adc %rdx,%r11
mulq %rbp # g[3]*g[3]*19
add %rax,%r8
mov 8*0(%rsp),%rax # g[2]
adc %rdx,%r9
lea (%rax,%rax),%rsi
mulq %rax # g[2]*g[2]
add %rax,%r14
mov %rbp,%rax
adc %rdx,%r15
mulq %rsi # 2*g[2]*g[3]*19
add %rax,%rbx
mov %rsi,%rax
adc %rdx,%rcx
mulq %rdi # 2*g[2]*g[4]*19
add %rax,%r8
adc %rdx,%r9
mov 8*4(%rsp),%rdi # restore 1st argument
jmp .Lreduce51
.align 32
.Lreduce51:
mov \$0x7ffffffffffff,%rbp
mov %r10,%rdx
shr \$51,%r10
shl \$13,%r11
and %rbp,%rdx # %rdx = g2 = h2 & mask
or %r10,%r11 # h2>>51
add %r11,%r12
adc \$0,%r13 # h3 += h2>>51
mov %rbx,%rax
shr \$51,%rbx
shl \$13,%rcx
and %rbp,%rax # %rax = g0 = h0 & mask
or %rbx,%rcx # h0>>51
add %rcx,%r8 # h1 += h0>>51
adc \$0,%r9
mov %r12,%rbx
shr \$51,%r12
shl \$13,%r13
and %rbp,%rbx # %rbx = g3 = h3 & mask
or %r12,%r13 # h3>>51
add %r13,%r14 # h4 += h3>>51
adc \$0,%r15
mov %r8,%rcx
shr \$51,%r8
shl \$13,%r9
and %rbp,%rcx # %rcx = g1 = h1 & mask
or %r8,%r9
add %r9,%rdx # g2 += h1>>51
mov %r14,%r10
shr \$51,%r14
shl \$13,%r15
and %rbp,%r10 # %r10 = g4 = h0 & mask
or %r14,%r15 # h0>>51
lea (%r15,%r15,8),%r14
lea (%r15,%r14,2),%r15
add %r15,%rax # g0 += (h0>>51)*19
mov %rdx,%r8
and %rbp,%rdx # g2 &= mask
shr \$51,%r8
add %r8,%rbx # g3 += g2>>51
mov %rax,%r9
and %rbp,%rax # g0 &= mask
shr \$51,%r9
add %r9,%rcx # g1 += g0>>51
mov %rax,8*0(%rdi) # save the result
mov %rcx,8*1(%rdi)
mov %rdx,8*2(%rdi)
mov %rbx,8*3(%rdi)
mov %r10,8*4(%rdi)
mov 8*5(%rsp),%r15
mov 8*6(%rsp),%r14
mov 8*7(%rsp),%r13
mov 8*8(%rsp),%r12
mov 8*9(%rsp),%rbx
mov 8*10(%rsp),%rbp
lea 8*11(%rsp),%rsp
ret
.size x25519_fe51_sqr,.-x25519_fe51_sqr
.globl x25519_fe51_mul121666
.type x25519_fe51_mul121666,\@function,2
.align 32
x25519_fe51_mul121666:
push %rbp
push %rbx
push %r12
push %r13
push %r14
push %r15
mov \$121666,%eax
lea -8*5(%rsp),%rsp
mulq 8*0(%rsi)
mov %rax,%rbx # %rbx:%rcx = h0
mov \$121666,%eax
mov %rdx,%rcx
mulq 8*1(%rsi)
mov %rax,%r8 # %r8:%r9 = h1
mov \$121666,%eax
mov %rdx,%r9
mulq 8*2(%rsi)
mov %rax,%r10 # %r10:%r11 = h2
mov \$121666,%eax
mov %rdx,%r11
mulq 8*3(%rsi)
mov %rax,%r12 # %r12:%r13 = h3
mov \$121666,%eax # f[0]
mov %rdx,%r13
mulq 8*4(%rsi)
mov %rax,%r14 # %r14:%r15 = h4
mov %rdx,%r15
jmp .Lreduce51
.size x25519_fe51_mul121666,.-x25519_fe51_mul121666
___
########################################################################
# Base 2^64 subroutines modulo 2*(2^255-19)
#
if ($addx) {
my ($acc0,$acc1,$acc2,$acc3,$acc4,$acc5,$acc6,$acc7) = map("%r$_",(8..15));
$code.=<<___;
.extern OPENSSL_ia32cap_P
.globl x25519_fe64_eligible
.type x25519_fe64_eligible,\@abi-omnipotent
.align 32
x25519_fe64_eligible:
mov OPENSSL_ia32cap_P+8(%rip),%ecx
xor %eax,%eax
and \$0x80100,%ecx
cmp \$0x80100,%ecx
cmove %ecx,%eax
ret
.size x25519_fe64_eligible,.-x25519_fe64_eligible
.globl x25519_fe64_mul
.type x25519_fe64_mul,\@function,3
.align 32
x25519_fe64_mul:
push %rbp
push %rbx
push %r12
push %r13
push %r14
push %r15
push %rdi # offload dst
lea -8*2(%rsp),%rsp
mov %rdx,%rax
mov 8*0(%rdx),%rbp # b[0]
mov 8*0(%rsi),%rdx # a[0]
mov 8*1(%rax),%rcx # b[1]
mov 8*2(%rax),$acc6 # b[2]
mov 8*3(%rax),$acc7 # b[3]
mulx %rbp,$acc0,%rax # a[0]*b[0]
xor %edi,%edi # cf=0,of=0
mulx %rcx,$acc1,%rbx # a[0]*b[1]
adcx %rax,$acc1
mulx $acc6,$acc2,%rax # a[0]*b[2]
adcx %rbx,$acc2
mulx $acc7,$acc3,$acc4 # a[0]*b[3]
mov 8*1(%rsi),%rdx # a[1]
adcx %rax,$acc3
mov $acc6,(%rsp) # offload b[2]
adcx %rdi,$acc4 # cf=0
mulx %rbp,%rax,%rbx # a[1]*b[0]
adox %rax,$acc1
adcx %rbx,$acc2
mulx %rcx,%rax,%rbx # a[1]*b[1]
adox %rax,$acc2
adcx %rbx,$acc3
mulx $acc6,%rax,%rbx # a[1]*b[2]
adox %rax,$acc3
adcx %rbx,$acc4
mulx $acc7,%rax,$acc5 # a[1]*b[3]
mov 8*2(%rsi),%rdx # a[2]
adox %rax,$acc4
adcx %rdi,$acc5 # cf=0
adox %rdi,$acc5 # of=0
mulx %rbp,%rax,%rbx # a[2]*b[0]
adcx %rax,$acc2
adox %rbx,$acc3
mulx %rcx,%rax,%rbx # a[2]*b[1]
adcx %rax,$acc3
adox %rbx,$acc4
mulx $acc6,%rax,%rbx # a[2]*b[2]
adcx %rax,$acc4
adox %rbx,$acc5
mulx $acc7,%rax,$acc6 # a[2]*b[3]
mov 8*3(%rsi),%rdx # a[3]
adcx %rax,$acc5
adox %rdi,$acc6 # of=0
adcx %rdi,$acc6 # cf=0
mulx %rbp,%rax,%rbx # a[3]*b[0]
adox %rax,$acc3
adcx %rbx,$acc4
mulx %rcx,%rax,%rbx # a[3]*b[1]
adox %rax,$acc4
adcx %rbx,$acc5
mulx (%rsp),%rax,%rbx # a[3]*b[2]
adox %rax,$acc5
adcx %rbx,$acc6
mulx $acc7,%rax,$acc7 # a[3]*b[3]
mov \$38,%edx
adox %rax,$acc6
adcx %rdi,$acc7 # cf=0
adox %rdi,$acc7 # of=0
jmp .Lreduce64
.size x25519_fe64_mul,.-x25519_fe64_mul
.globl x25519_fe64_sqr
.type x25519_fe64_sqr,\@function,2
.align 32
x25519_fe64_sqr:
push %rbp
push %rbx
push %r12
push %r13
push %r14
push %r15
push %rdi # offload dst
lea -8*2(%rsp),%rsp
mov 8*0(%rsi),%rdx # a[0]
mov 8*1(%rsi),%rcx # a[1]
mov 8*2(%rsi),%rbp # a[2]
mov 8*3(%rsi),%rsi # a[3]
################################################################
mulx %rdx,$acc0,$acc7 # a[0]*a[0]
mulx %rcx,$acc1,%rax # a[0]*a[1]
xor %edi,%edi # cf=0,of=0
mulx %rbp,$acc2,%rbx # a[0]*a[2]
adcx %rax,$acc2
mulx %rsi,$acc3,$acc4 # a[0]*a[3]
mov %rcx,%rdx # a[1]
adcx %rbx,$acc3
adcx %rdi,$acc4 # cf=0
################################################################
mulx %rbp,%rax,%rbx # a[1]*a[2]
adox %rax,$acc3
adcx %rbx,$acc4
mulx %rsi,%rax,$acc5 # a[1]*a[3]
mov %rbp,%rdx # a[2]
adox %rax,$acc4
adcx %rdi,$acc5
################################################################
mulx %rsi,%rax,$acc6 # a[2]*a[3]
mov %rcx,%rdx # a[1]
adox %rax,$acc5
adcx %rdi,$acc6 # cf=0
adox %rdi,$acc6 # of=0
adcx $acc1,$acc1 # acc1:6<<1
adox $acc7,$acc1
adcx $acc2,$acc2
mulx %rdx,%rax,%rbx # a[1]*a[1]
mov %rbp,%rdx # a[2]
adcx $acc3,$acc3
adox %rax,$acc2
adcx $acc4,$acc4
adox %rbx,$acc3
mulx %rdx,%rax,%rbx # a[2]*a[2]
mov %rsi,%rdx # a[3]
adcx $acc5,$acc5
adox %rax,$acc4
adcx $acc6,$acc6
adox %rbx,$acc5
mulx %rdx,%rax,$acc7 # a[3]*a[3]
mov \$38,%edx
adox %rax,$acc6
adcx %rdi,$acc7 # cf=0
adox %rdi,$acc7 # of=0
jmp .Lreduce64
.align 32
.Lreduce64:
mulx $acc4,%rax,%rbx
adcx %rax,$acc0
adox %rbx,$acc1
mulx $acc5,%rax,%rbx
adcx %rax,$acc1
adox %rbx,$acc2
mulx $acc6,%rax,%rbx
adcx %rax,$acc2
adox %rbx,$acc3
mulx $acc7,%rax,$acc4
adcx %rax,$acc3
adox %rdi,$acc4
adcx %rdi,$acc4
mov 8*2(%rsp),%rdi # restore dst
imulq %rdx,$acc4
add $acc4,$acc0
adc \$0,$acc1
adc \$0,$acc2
adc \$0,$acc3
sbb %rax,%rax # cf -> mask
and \$38,%rax
add %rax,$acc0
mov $acc1,8*1(%rdi)
mov $acc2,8*2(%rdi)
mov $acc3,8*3(%rdi)
mov $acc0,8*0(%rdi)
mov 8*3(%rsp),%r15
mov 8*4(%rsp),%r14
mov 8*5(%rsp),%r13
mov 8*6(%rsp),%r12
mov 8*7(%rsp),%rbx
mov 8*8(%rsp),%rbp
lea 8*9(%rsp),%rsp
ret
.size x25519_fe64_sqr,.-x25519_fe64_sqr
.globl x25519_fe64_mul121666
.type x25519_fe64_mul121666,\@function,2
.align 32
x25519_fe64_mul121666:
mov \$121666,%edx
mulx 8*0(%rsi),$acc0,%rcx
mulx 8*1(%rsi),$acc1,%rax
add %rcx,$acc1
mulx 8*2(%rsi),$acc2,%rcx
adc %rax,$acc2
mulx 8*3(%rsi),$acc3,%rax
adc %rcx,$acc3
adc \$0,%rax
imulq \$38,%rax,%rax
add %rax,$acc0
adc \$0,$acc1
adc \$0,$acc2
adc \$0,$acc3
sbb %rax,%rax # cf -> mask
and \$38,%rax
add %rax,$acc0
mov $acc1,8*1(%rdi)
mov $acc2,8*2(%rdi)
mov $acc3,8*3(%rdi)
mov $acc0,8*0(%rdi)
ret
.size x25519_fe64_mul121666,.-x25519_fe64_mul121666
.globl x25519_fe64_add
.type x25519_fe64_add,\@function,3
.align 32
x25519_fe64_add:
mov 8*0(%rsi),$acc0
mov 8*1(%rsi),$acc1
mov 8*2(%rsi),$acc2
mov 8*3(%rsi),$acc3
add 8*0(%rdx),$acc0
adc 8*1(%rdx),$acc1
adc 8*2(%rdx),$acc2
adc 8*3(%rdx),$acc3
sbb %rax,%rax # cf -> mask
and \$38,%rax
add %rax,$acc0
adc \$0,$acc1
mov $acc0,8*0(%rdi)
adc \$0,$acc2
mov $acc1,8*1(%rdi)
adc \$0,$acc3
mov $acc2,8*2(%rdi)
mov $acc3,8*3(%rdi)
ret
.size x25519_fe64_add,.-x25519_fe64_add
.globl x25519_fe64_sub
.type x25519_fe64_sub,\@function,3
.align 32
x25519_fe64_sub:
mov 8*0(%rsi),$acc0
mov 8*1(%rsi),$acc1
mov 8*2(%rsi),$acc2
mov 8*3(%rsi),$acc3
sub 8*0(%rdx),$acc0
sbb 8*1(%rdx),$acc1
sbb 8*2(%rdx),$acc2
sbb 8*3(%rdx),$acc3
sbb %rax,%rax # cf -> mask
and \$38,%rax
sub %rax,$acc0
sbb \$0,$acc1
mov $acc0,8*0(%rdi)
sbb \$0,$acc2
mov $acc1,8*1(%rdi)
sbb \$0,$acc3
mov $acc2,8*2(%rdi)
mov $acc3,8*3(%rdi)
ret
.size x25519_fe64_sub,.-x25519_fe64_sub
.globl x25519_fe64_tobytes
.type x25519_fe64_tobytes,\@function,2
.align 32
x25519_fe64_tobytes:
mov 8*0(%rsi),$acc0
mov 8*1(%rsi),$acc1
mov 8*2(%rsi),$acc2
mov 8*3(%rsi),$acc3
################################# reduction modulo 2^255-19
lea ($acc3,$acc3),%rax
sar \$63,$acc3 # most significant bit -> mask
shr \$1,%rax # most significant bit cleared
and \$19,$acc3
add $acc3,$acc0
adc \$0,$acc1
adc \$0,$acc2
adc \$0,%rax
lea (%rax,%rax),$acc3
sar \$63,%rax # most significant bit -> mask
shr \$1,$acc3 # most significant bit cleared
and \$19,%rax
add %rax,$acc0
mov $acc1,8*1(%rdi)
mov $acc2,8*2(%rdi)
mov $acc3,8*3(%rdi)
mov $acc0,8*0(%rdi)
ret
.size x25519_fe64_tobytes,.-x25519_fe64_tobytes
___
} else {
$code.=<<___;
.globl x25519_fe64_eligible
.type x25519_fe64_eligible,\@abi-omnipotent
.align 32
x25519_fe64_eligible:
xor %eax,%eax
ret
.size x25519_fe64_eligible,.-x25519_fe64_eligible
.globl x25519_fe64_mul
.type x25519_fe64_mul,\@abi-omnipotent
.globl x25519_fe64_sqr
.globl x25519_fe64_mul121666
.globl x25519_fe64_add
.globl x25519_fe64_sub
.globl x25519_fe64_tobytes
x25519_fe64_mul:
x25519_fe64_sqr:
x25519_fe64_mul121666:
x25519_fe64_add:
x25519_fe64_sub:
x25519_fe64_tobytes:
.byte 0x0f,0x0b # ud2
ret
.size x25519_fe64_mul,.-x25519_fe64_mul
___
}
$code.=<<___;
.asciz "X25519 primitives for x86_64, CRYPTOGAMS by <appro\@openssl.org>"
___
$code =~ s/\`([^\`]*)\`/eval $1/gem;
print $code;
close STDOUT;