#!/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/.
# ====================================================================
#
# sha1_block procedure for x86_64.
#
# It was brought to my attention that on EM64T compiler-generated code
# was far behind 32-bit assembler implementation. This is unlike on
# Opteron where compiler-generated code was only 15% behind 32-bit
# assembler, which originally made it hard to motivate the effort.
# There was suggestion to mechanically translate 32-bit code, but I
# dismissed it, reasoning that x86_64 offers enough register bank
# capacity to fully utilize SHA-1 parallelism. Therefore this fresh
# implementation:-) However! While 64-bit code does performs better
# on Opteron, I failed to beat 32-bit assembler on EM64T core. Well,
# x86_64 does offer larger *addressable* bank, but out-of-order core
# reaches for even more registers through dynamic aliasing, and EM64T
# core must have managed to run-time optimize even 32-bit code just as
# good as 64-bit one. Performance improvement is summarized in the
# following table:
#
#		gcc 3.4		32-bit asm	cycles/byte
# Opteron	+45%		+20%		6.8
# Xeon P4	+65%		+0%		9.9
# Core2		+60%		+10%		8.8

$output=shift;

$0 =~ m/(.*[\/\\])[^\/\\]+$/; $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 STDOUT,"| $^X $xlate $output";

$ctx="%rdi";	# 1st arg
$inp="%rsi";	# 2nd arg
$num="%rdx";	# 3rd arg

# reassign arguments in order to produce more compact code
$ctx="%r8";
$inp="%r9";
$num="%r10";

$xi="%eax";
$t0="%ebx";
$t1="%ecx";
$A="%edx";
$B="%esi";
$C="%edi";
$D="%ebp";
$E="%r11d";
$T="%r12d";

@V=($A,$B,$C,$D,$E,$T);

sub PROLOGUE {
my $func=shift;
$code.=<<___;
.globl	$func
.type	$func,\@function,3
.align	16
$func:
	push	%rbx
	push	%rbp
	push	%r12
	mov	%rsp,%rax
	mov	%rdi,$ctx	# reassigned argument
	sub	\$`8+16*4`,%rsp
	mov	%rsi,$inp	# reassigned argument
	and	\$-64,%rsp
	mov	%rdx,$num	# reassigned argument
	mov	%rax,`16*4`(%rsp)

	mov	0($ctx),$A
	mov	4($ctx),$B
	mov	8($ctx),$C
	mov	12($ctx),$D
	mov	16($ctx),$E
___
}

sub EPILOGUE {
my $func=shift;
$code.=<<___;
	mov	`16*4`(%rsp),%rsp
	pop	%r12
	pop	%rbp
	pop	%rbx
	ret
.size	$func,.-$func
___
}

sub BODY_00_19 {
my ($i,$a,$b,$c,$d,$e,$f,$host)=@_;
my $j=$i+1;
$code.=<<___ if ($i==0);
	mov	`4*$i`($inp),$xi	
	`"bswap	$xi"	if(!defined($host))`
	mov	$xi,`4*$i`(%rsp)
___
$code.=<<___ if ($i<15);
	lea	0x5a827999($xi,$e),$f
	mov	$c,$t0
	mov	`4*$j`($inp),$xi
	mov	$a,$e
	xor	$d,$t0
	`"bswap	$xi"	if(!defined($host))`	
	rol	\$5,$e
	and	$b,$t0
	mov	$xi,`4*$j`(%rsp)
	add	$e,$f
	xor	$d,$t0
	rol	\$30,$b
	add	$t0,$f
___
$code.=<<___ if ($i>=15);
	lea	0x5a827999($xi,$e),$f
	mov	`4*($j%16)`(%rsp),$xi
	mov	$c,$t0
	mov	$a,$e
	xor	`4*(($j+2)%16)`(%rsp),$xi
	xor	$d,$t0
	rol	\$5,$e
	xor	`4*(($j+8)%16)`(%rsp),$xi
	and	$b,$t0
	add	$e,$f
	xor	`4*(($j+13)%16)`(%rsp),$xi
	xor	$d,$t0
	rol	\$30,$b
	add	$t0,$f
	rol	\$1,$xi
	mov	$xi,`4*($j%16)`(%rsp)
___
}

sub BODY_20_39 {
my ($i,$a,$b,$c,$d,$e,$f)=@_;
my $j=$i+1;
my $K=($i<40)?0x6ed9eba1:0xca62c1d6;
$code.=<<___ if ($i<79);
	lea	$K($xi,$e),$f
	mov	`4*($j%16)`(%rsp),$xi
	mov	$c,$t0
	mov	$a,$e
	xor	`4*(($j+2)%16)`(%rsp),$xi
	xor	$b,$t0
	rol	\$5,$e
	xor	`4*(($j+8)%16)`(%rsp),$xi
	xor	$d,$t0
	add	$e,$f
	xor	`4*(($j+13)%16)`(%rsp),$xi
	rol	\$30,$b
	add	$t0,$f
	rol	\$1,$xi
___
$code.=<<___ if ($i<76);
	mov	$xi,`4*($j%16)`(%rsp)
___
$code.=<<___ if ($i==79);
	lea	$K($xi,$e),$f
	mov	$c,$t0
	mov	$a,$e
	xor	$b,$t0
	rol	\$5,$e
	xor	$d,$t0
	add	$e,$f
	rol	\$30,$b
	add	$t0,$f
___
}

sub BODY_40_59 {
my ($i,$a,$b,$c,$d,$e,$f)=@_;
my $j=$i+1;
$code.=<<___;
	lea	0x8f1bbcdc($xi,$e),$f
	mov	`4*($j%16)`(%rsp),$xi
	mov	$b,$t0
	mov	$b,$t1
	xor	`4*(($j+2)%16)`(%rsp),$xi
	mov	$a,$e
	and	$c,$t0
	xor	`4*(($j+8)%16)`(%rsp),$xi
	or	$c,$t1
	rol	\$5,$e
	xor	`4*(($j+13)%16)`(%rsp),$xi
	and	$d,$t1
	add	$e,$f
	rol	\$1,$xi
	or	$t1,$t0
	rol	\$30,$b
	mov	$xi,`4*($j%16)`(%rsp)
	add	$t0,$f
___
}

$code=".text\n";

&PROLOGUE("sha1_block_data_order");
$code.=".align	4\n.Lloop:\n";
for($i=0;$i<20;$i++)	{ &BODY_00_19($i,@V); unshift(@V,pop(@V)); }
for(;$i<40;$i++)	{ &BODY_20_39($i,@V); unshift(@V,pop(@V)); }
for(;$i<60;$i++)	{ &BODY_40_59($i,@V); unshift(@V,pop(@V)); }
for(;$i<80;$i++)	{ &BODY_20_39($i,@V); unshift(@V,pop(@V)); }
$code.=<<___;
	add	0($ctx),$E
	add	4($ctx),$T
	add	8($ctx),$A
	add	12($ctx),$B
	add	16($ctx),$C
	mov	$E,0($ctx)
	mov	$T,4($ctx)
	mov	$A,8($ctx)
	mov	$B,12($ctx)
	mov	$C,16($ctx)

	xchg	$E,$A	# mov	$E,$A
	xchg	$T,$B	# mov	$T,$B
	xchg	$E,$C	# mov	$A,$C
	xchg	$T,$D	# mov	$B,$D
			# mov	$C,$E
	lea	`16*4`($inp),$inp
	sub	\$1,$num
	jnz	.Lloop
___
&EPILOGUE("sha1_block_data_order");
$code.=<<___;
.asciz	"SHA1 block transform for x86_64, CRYPTOGAMS by <appro\@openssl.org>"
___

####################################################################

$code =~ s/\`([^\`]*)\`/eval $1/gem;
print $code;
close STDOUT;