crypto/modes/asm/ghashv8-armx.pl - boringssl - Git at Google

 #!/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/.
 # ====================================================================
 #
 # GHASH for ARMv8 Crypto Extension, 64-bit polynomial multiplication.
 #
 # June 2014
 #
 # Initial version was developed in tight cooperation with Ard
 # Biesheuvel <ard.biesheuvel@linaro.org> from bits-n-pieces from
 # other assembly modules. Just like aesv8-armx.pl this module
 # supports both AArch32 and AArch64 execution modes.
 #
 # July 2014
 #
 # Implement 2x aggregated reduction [see ghash-x86.pl for background
 # information].
 #
 # Current performance in cycles per processed byte:
 #
 #		PMULL[2]	32-bit NEON(*)
 # Apple A7	0.92		5.62
 # Cortex-A53	1.01		8.39
 # Cortex-A57	1.17		7.61
 # Denver	0.71		6.02
 #
 # (*)	presented for reference/comparison purposes;

 $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;

 $Xi="x0";	# argument block
 $Htbl="x1";
 $inp="x2";
 $len="x3";

 $inc="x12";

 {
 my ($Xl,$Xm,$Xh,$IN)=map("q$_",(0..3));
 my ($t0,$t1,$t2,$xC2,$H,$Hhl,$H2)=map("q$_",(8..14));

 $code=<<___;
 #include "arm_arch.h"

 .text
 ___
 $code.=<<___ if ($flavour =~ /64/);
 #if !defined(__clang__)
 .arch  armv8-a+crypto
 #endif
 ___
 $code.=".fpu	neon\n.code	32\n"	if ($flavour !~ /64/);

 ################################################################################
 # void gcm_init_v8(u128 Htable[16],const u64 H[2]);
 #
 # input:	128-bit H - secret parameter E(K,0^128)
 # output:	precomputed table filled with degrees of twisted H;
 #		H is twisted to handle reverse bitness of GHASH;
 #		only few of 16 slots of Htable[16] are used;
 #		data is opaque to outside world (which allows to
 #		optimize the code independently);
 #
 $code.=<<___;
 .global	gcm_init_v8
 .type	gcm_init_v8,%function
 .align	4
 gcm_init_v8:
 	vld1.64		{$t1},[x1]		@ load input H
 	vmov.i8		$xC2,#0xe1
 	vshl.i64	$xC2,$xC2,#57		@ 0xc2.0
 	vext.8		$IN,$t1,$t1,#8
 	vshr.u64	$t2,$xC2,#63
 	vdup.32		$t1,${t1}[1]
 	vext.8		$t0,$t2,$xC2,#8		@ t0=0xc2....01
 	vshr.u64	$t2,$IN,#63
 	vshr.s32	$t1,$t1,#31		@ broadcast carry bit
 	vand		$t2,$t2,$t0
 	vshl.i64	$IN,$IN,#1
 	vext.8		$t2,$t2,$t2,#8
 	vand		$t0,$t0,$t1
 	vorr		$IN,$IN,$t2		@ H<<<=1
 	veor		$H,$IN,$t0		@ twisted H
 	vst1.64		{$H},[x0],#16		@ store Htable[0]

 	@ calculate H^2
 	vext.8		$t0,$H,$H,#8		@ Karatsuba pre-processing
 	vpmull.p64	$Xl,$H,$H
 	veor		$t0,$t0,$H
 	vpmull2.p64	$Xh,$H,$H
 	vpmull.p64	$Xm,$t0,$t0

 	vext.8		$t1,$Xl,$Xh,#8		@ Karatsuba post-processing
 	veor		$t2,$Xl,$Xh
 	veor		$Xm,$Xm,$t1
 	veor		$Xm,$Xm,$t2
 	vpmull.p64	$t2,$Xl,$xC2		@ 1st phase

 	vmov		$Xh#lo,$Xm#hi		@ Xh|Xm - 256-bit result
 	vmov		$Xm#hi,$Xl#lo		@ Xm is rotated Xl
 	veor		$Xl,$Xm,$t2

 	vext.8		$t2,$Xl,$Xl,#8		@ 2nd phase
 	vpmull.p64	$Xl,$Xl,$xC2
 	veor		$t2,$t2,$Xh
 	veor		$H2,$Xl,$t2

 	vext.8		$t1,$H2,$H2,#8		@ Karatsuba pre-processing
 	veor		$t1,$t1,$H2
 	vext.8		$Hhl,$t0,$t1,#8		@ pack Karatsuba pre-processed
 	vst1.64		{$Hhl-$H2},[x0]		@ store Htable[1..2]

 	ret
 .size	gcm_init_v8,.-gcm_init_v8
 ___
 ################################################################################
 # void gcm_gmult_v8(u64 Xi[2],const u128 Htable[16]);
 #
 # input:	Xi - current hash value;
 #		Htable - table precomputed in gcm_init_v8;
 # output:	Xi - next hash value Xi;
 #
 $code.=<<___;
 .global	gcm_gmult_v8
 .type	gcm_gmult_v8,%function
 .align	4
 gcm_gmult_v8:
 	vld1.64		{$t1},[$Xi]		@ load Xi
 	vmov.i8		$xC2,#0xe1
 	vld1.64		{$H-$Hhl},[$Htbl]	@ load twisted H, ...
 	vshl.u64	$xC2,$xC2,#57
 #ifndef __ARMEB__
 	vrev64.8	$t1,$t1
 #endif
 	vext.8		$IN,$t1,$t1,#8

 	vpmull.p64	$Xl,$H,$IN		@ H.lo·Xi.lo
 	veor		$t1,$t1,$IN		@ Karatsuba pre-processing
 	vpmull2.p64	$Xh,$H,$IN		@ H.hi·Xi.hi
 	vpmull.p64	$Xm,$Hhl,$t1		@ (H.lo+H.hi)·(Xi.lo+Xi.hi)

 	vext.8		$t1,$Xl,$Xh,#8		@ Karatsuba post-processing
 	veor		$t2,$Xl,$Xh
 	veor		$Xm,$Xm,$t1
 	veor		$Xm,$Xm,$t2
 	vpmull.p64	$t2,$Xl,$xC2		@ 1st phase of reduction

 	vmov		$Xh#lo,$Xm#hi		@ Xh|Xm - 256-bit result
 	vmov		$Xm#hi,$Xl#lo		@ Xm is rotated Xl
 	veor		$Xl,$Xm,$t2

 	vext.8		$t2,$Xl,$Xl,#8		@ 2nd phase of reduction
 	vpmull.p64	$Xl,$Xl,$xC2
 	veor		$t2,$t2,$Xh
 	veor		$Xl,$Xl,$t2

 #ifndef __ARMEB__
 	vrev64.8	$Xl,$Xl
 #endif
 	vext.8		$Xl,$Xl,$Xl,#8
 	vst1.64		{$Xl},[$Xi]		@ write out Xi

 	ret
 .size	gcm_gmult_v8,.-gcm_gmult_v8
 ___
 ################################################################################
 # void gcm_ghash_v8(u64 Xi[2],const u128 Htable[16],const u8 *inp,size_t len);
 #
 # input:	table precomputed in gcm_init_v8;
 #		current hash value Xi;
 #		pointer to input data;
 #		length of input data in bytes, but divisible by block size;
 # output:	next hash value Xi;
 #
 $code.=<<___;
 .global	gcm_ghash_v8
 .type	gcm_ghash_v8,%function
 .align	4
 gcm_ghash_v8:
 ___
 $code.=<<___		if ($flavour !~ /64/);
 	vstmdb		sp!,{d8-d15}		@ 32-bit ABI says so
 ___
 $code.=<<___;
 	vld1.64		{$Xl},[$Xi]		@ load [rotated] Xi
 						@ "[rotated]" means that
 						@ loaded value would have
 						@ to be rotated in order to
 						@ make it appear as in
 						@ alorithm specification
 	subs		$len,$len,#32		@ see if $len is 32 or larger
 	mov		$inc,#16		@ $inc is used as post-
 						@ increment for input pointer;
 						@ as loop is modulo-scheduled
 						@ $inc is zeroed just in time
 						@ to preclude oversteping
 						@ inp[len], which means that
 						@ last block[s] are actually
 						@ loaded twice, but last
 						@ copy is not processed
 	vld1.64		{$H-$Hhl},[$Htbl],#32	@ load twisted H, ..., H^2
 	vmov.i8		$xC2,#0xe1
 	vld1.64		{$H2},[$Htbl]
 	cclr		$inc,eq			@ is it time to zero $inc?
 	vext.8		$Xl,$Xl,$Xl,#8		@ rotate Xi
 	vld1.64		{$t0},[$inp],#16	@ load [rotated] I[0]
 	vshl.u64	$xC2,$xC2,#57		@ compose 0xc2.0 constant
 #ifndef __ARMEB__
 	vrev64.8	$t0,$t0
 	vrev64.8	$Xl,$Xl
 #endif
 	vext.8		$IN,$t0,$t0,#8		@ rotate I[0]
 	b.lo		.Lodd_tail_v8		@ $len was less than 32
 ___
 { my ($Xln,$Xmn,$Xhn,$In) = map("q$_",(4..7));
 	#######
 	# Xi+2 =[H*(Ii+1 + Xi+1)] mod P =
 	#	[(H*Ii+1) + (H*Xi+1)] mod P =
 	#	[(H*Ii+1) + H^2*(Ii+Xi)] mod P
 	#
 $code.=<<___;
 	vld1.64		{$t1},[$inp],$inc	@ load [rotated] I[1]
 #ifndef __ARMEB__
 	vrev64.8	$t1,$t1
 #endif
 	vext.8		$In,$t1,$t1,#8
 	veor		$IN,$IN,$Xl		@ I[i]^=Xi
 	vpmull.p64	$Xln,$H,$In		@ H·Ii+1
 	veor		$t1,$t1,$In		@ Karatsuba pre-processing
 	vpmull2.p64	$Xhn,$H,$In
 	b		.Loop_mod2x_v8

 .align	4
 .Loop_mod2x_v8:
 	vext.8		$t2,$IN,$IN,#8
 	subs		$len,$len,#32		@ is there more data?
 	vpmull.p64	$Xl,$H2,$IN		@ H^2.lo·Xi.lo
 	cclr		$inc,lo			@ is it time to zero $inc?

 	 vpmull.p64	$Xmn,$Hhl,$t1
 	veor		$t2,$t2,$IN		@ Karatsuba pre-processing
 	vpmull2.p64	$Xh,$H2,$IN		@ H^2.hi·Xi.hi
 	veor		$Xl,$Xl,$Xln		@ accumulate
 	vpmull2.p64	$Xm,$Hhl,$t2		@ (H^2.lo+H^2.hi)·(Xi.lo+Xi.hi)
 	 vld1.64	{$t0},[$inp],$inc	@ load [rotated] I[i+2]

 	veor		$Xh,$Xh,$Xhn
 	 cclr		$inc,eq			@ is it time to zero $inc?
 	veor		$Xm,$Xm,$Xmn

 	vext.8		$t1,$Xl,$Xh,#8		@ Karatsuba post-processing
 	veor		$t2,$Xl,$Xh
 	veor		$Xm,$Xm,$t1
 	 vld1.64	{$t1},[$inp],$inc	@ load [rotated] I[i+3]
 #ifndef __ARMEB__
 	 vrev64.8	$t0,$t0
 #endif
 	veor		$Xm,$Xm,$t2
 	vpmull.p64	$t2,$Xl,$xC2		@ 1st phase of reduction

 #ifndef __ARMEB__
 	 vrev64.8	$t1,$t1
 #endif
 	vmov		$Xh#lo,$Xm#hi		@ Xh|Xm - 256-bit result
 	vmov		$Xm#hi,$Xl#lo		@ Xm is rotated Xl
 	 vext.8		$In,$t1,$t1,#8
 	 vext.8		$IN,$t0,$t0,#8
 	veor		$Xl,$Xm,$t2
 	 vpmull.p64	$Xln,$H,$In		@ H·Ii+1
 	veor		$IN,$IN,$Xh		@ accumulate $IN early

 	vext.8		$t2,$Xl,$Xl,#8		@ 2nd phase of reduction
 	vpmull.p64	$Xl,$Xl,$xC2
 	veor		$IN,$IN,$t2
 	 veor		$t1,$t1,$In		@ Karatsuba pre-processing
 	veor		$IN,$IN,$Xl
 	 vpmull2.p64	$Xhn,$H,$In
 	b.hs		.Loop_mod2x_v8		@ there was at least 32 more bytes

 	veor		$Xh,$Xh,$t2
 	vext.8		$IN,$t0,$t0,#8		@ re-construct $IN
 	adds		$len,$len,#32		@ re-construct $len
 	veor		$Xl,$Xl,$Xh		@ re-construct $Xl
 	b.eq		.Ldone_v8		@ is $len zero?
 ___
 }
 $code.=<<___;
 .Lodd_tail_v8:
 	vext.8		$t2,$Xl,$Xl,#8
 	veor		$IN,$IN,$Xl		@ inp^=Xi
 	veor		$t1,$t0,$t2		@ $t1 is rotated inp^Xi

 	vpmull.p64	$Xl,$H,$IN		@ H.lo·Xi.lo
 	veor		$t1,$t1,$IN		@ Karatsuba pre-processing
 	vpmull2.p64	$Xh,$H,$IN		@ H.hi·Xi.hi
 	vpmull.p64	$Xm,$Hhl,$t1		@ (H.lo+H.hi)·(Xi.lo+Xi.hi)

 	vext.8		$t1,$Xl,$Xh,#8		@ Karatsuba post-processing
 	veor		$t2,$Xl,$Xh
 	veor		$Xm,$Xm,$t1
 	veor		$Xm,$Xm,$t2
 	vpmull.p64	$t2,$Xl,$xC2		@ 1st phase of reduction

 	vmov		$Xh#lo,$Xm#hi		@ Xh|Xm - 256-bit result
 	vmov		$Xm#hi,$Xl#lo		@ Xm is rotated Xl
 	veor		$Xl,$Xm,$t2

 	vext.8		$t2,$Xl,$Xl,#8		@ 2nd phase of reduction
 	vpmull.p64	$Xl,$Xl,$xC2
 	veor		$t2,$t2,$Xh
 	veor		$Xl,$Xl,$t2

 .Ldone_v8:
 #ifndef __ARMEB__
 	vrev64.8	$Xl,$Xl
 #endif
 	vext.8		$Xl,$Xl,$Xl,#8
 	vst1.64		{$Xl},[$Xi]		@ write out Xi

 ___
 $code.=<<___		if ($flavour !~ /64/);
 	vldmia		sp!,{d8-d15}		@ 32-bit ABI says so
 ___
 $code.=<<___;
 	ret
 .size	gcm_ghash_v8,.-gcm_ghash_v8
 ___
 }
 $code.=<<___;
 .asciz  "GHASH for ARMv8, CRYPTOGAMS by <appro\@openssl.org>"
 .align  2
 ___

 if ($flavour =~ /64/) {			######## 64-bit code
     sub unvmov {
 	my $arg=shift;

 	$arg =~ m/q([0-9]+)#(lo|hi),\s*q([0-9]+)#(lo|hi)/o &&
 	sprintf	"ins	v%d.d[%d],v%d.d[%d]",$1,($2 eq "lo")?0:1,$3,($4 eq "lo")?0:1;
     }
     foreach(split("\n",$code)) {
 	s/cclr\s+([wx])([^,]+),\s*([a-z]+)/csel	$1$2,$1zr,$1$2,$3/o	or
 	s/vmov\.i8/movi/o		or	# fix up legacy mnemonics
 	s/vmov\s+(.*)/unvmov($1)/geo	or
 	s/vext\.8/ext/o			or
 	s/vshr\.s/sshr\.s/o		or
 	s/vshr/ushr/o			or
 	s/^(\s+)v/$1/o			or	# strip off v prefix
 	s/\bbx\s+lr\b/ret/o;

 	s/\bq([0-9]+)\b/"v".($1<8?$1:$1+8).".16b"/geo;	# old->new registers
 	s/@\s/\/\//o;				# old->new style commentary

 	# fix up remainig legacy suffixes
 	s/\.[ui]?8(\s)/$1/o;
 	s/\.[uis]?32//o and s/\.16b/\.4s/go;
 	m/\.p64/o and s/\.16b/\.1q/o;		# 1st pmull argument
 	m/l\.p64/o and s/\.16b/\.1d/go;		# 2nd and 3rd pmull arguments
 	s/\.[uisp]?64//o and s/\.16b/\.2d/go;
 	s/\.[42]([sd])\[([0-3])\]/\.$1\[$2\]/o;

 	print $_,"\n";
     }
 } else {				######## 32-bit code
     sub unvdup32 {
 	my $arg=shift;

 	$arg =~ m/q([0-9]+),\s*q([0-9]+)\[([0-3])\]/o &&
 	sprintf	"vdup.32	q%d,d%d[%d]",$1,2*$2+($3>>1),$3&1;
     }
     sub unvpmullp64 {
 	my ($mnemonic,$arg)=@_;

 	if ($arg =~ m/q([0-9]+),\s*q([0-9]+),\s*q([0-9]+)/o) {
 	    my $word = 0xf2a00e00|(($1&7)<<13)|(($1&8)<<19)
 				 |(($2&7)<<17)|(($2&8)<<4)
 				 |(($3&7)<<1) |(($3&8)<<2);
 	    $word |= 0x00010001	 if ($mnemonic =~ "2");
 	    # since ARMv7 instructions are always encoded little-endian.
 	    # correct solution is to use .inst directive, but older
 	    # assemblers don't implement it:-(
 	    sprintf ".byte\t0x%02x,0x%02x,0x%02x,0x%02x\t@ %s %s",
 			$word&0xff,($word>>8)&0xff,
 			($word>>16)&0xff,($word>>24)&0xff,
 			$mnemonic,$arg;
 	}
     }

     foreach(split("\n",$code)) {
 	s/\b[wx]([0-9]+)\b/r$1/go;		# new->old registers
 	s/\bv([0-9])\.[12468]+[bsd]\b/q$1/go;	# new->old registers
 	s/\/\/\s?/@ /o;				# new->old style commentary

 	# fix up remainig new-style suffixes
 	s/\],#[0-9]+/]!/o;

 	s/cclr\s+([^,]+),\s*([a-z]+)/mov$2	$1,#0/o			or
 	s/vdup\.32\s+(.*)/unvdup32($1)/geo				or
 	s/v?(pmull2?)\.p64\s+(.*)/unvpmullp64($1,$2)/geo		or
 	s/\bq([0-9]+)#(lo|hi)/sprintf "d%d",2*$1+($2 eq "hi")/geo	or
 	s/^(\s+)b\./$1b/o						or
 	s/^(\s+)ret/$1bx\tlr/o;

 	print $_,"\n";
     }
 }

 close STDOUT; # enforce flush
	#!/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/.
	# ====================================================================
	#
	# GHASH for ARMv8 Crypto Extension, 64-bit polynomial multiplication.
	#
	# June 2014
	#
	# Initial version was developed in tight cooperation with Ard
	# Biesheuvel <ard.biesheuvel@linaro.org> from bits-n-pieces from
	# other assembly modules. Just like aesv8-armx.pl this module
	# supports both AArch32 and AArch64 execution modes.
	#
	# July 2014
	#
	# Implement 2x aggregated reduction [see ghash-x86.pl for background
	# information].
	#
	# Current performance in cycles per processed byte:
	#
	# PMULL[2] 32-bit NEON(*)
	# Apple A7 0.92 5.62
	# Cortex-A53 1.01 8.39
	# Cortex-A57 1.17 7.61
	# Denver 0.71 6.02
	#
	# (*) presented for reference/comparison purposes;

	$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;

	$Xi="x0"; # argument block
	$Htbl="x1";
	$inp="x2";
	$len="x3";

	$inc="x12";

	{
	my ($Xl,$Xm,$Xh,$IN)=map("q$_",(0..3));
	my ($t0,$t1,$t2,$xC2,$H,$Hhl,$H2)=map("q$_",(8..14));

	$code=<<___;
	#include "arm_arch.h"

	.text
	___
	$code.=<<___ if ($flavour =~ /64/);
	#if !defined(__clang__)
	.arch armv8-a+crypto
	#endif
	___
	$code.=".fpu neon\n.code 32\n" if ($flavour !~ /64/);

	################################################################################
	# void gcm_init_v8(u128 Htable[16],const u64 H[2]);
	#
	# input: 128-bit H - secret parameter E(K,0^128)
	# output: precomputed table filled with degrees of twisted H;
	# H is twisted to handle reverse bitness of GHASH;
	# only few of 16 slots of Htable[16] are used;
	# data is opaque to outside world (which allows to
	# optimize the code independently);
	#
	$code.=<<___;
	.global gcm_init_v8
	.type gcm_init_v8,%function
	.align 4
	gcm_init_v8:
	vld1.64 {$t1},[x1] @ load input H
	vmov.i8 $xC2,#0xe1
	vshl.i64 $xC2,$xC2,#57 @ 0xc2.0
	vext.8 $IN,$t1,$t1,#8
	vshr.u64 $t2,$xC2,#63
	vdup.32 $t1,${t1}[1]
	vext.8 $t0,$t2,$xC2,#8 @ t0=0xc2....01
	vshr.u64 $t2,$IN,#63
	vshr.s32 $t1,$t1,#31 @ broadcast carry bit
	vand $t2,$t2,$t0
	vshl.i64 $IN,$IN,#1
	vext.8 $t2,$t2,$t2,#8
	vand $t0,$t0,$t1
	vorr $IN,$IN,$t2 @ H<<<=1
	veor $H,$IN,$t0 @ twisted H
	vst1.64 {$H},[x0],#16 @ store Htable[0]

	@ calculate H^2
	vext.8 $t0,$H,$H,#8 @ Karatsuba pre-processing
	vpmull.p64 $Xl,$H,$H
	veor $t0,$t0,$H
	vpmull2.p64 $Xh,$H,$H
	vpmull.p64 $Xm,$t0,$t0

	vext.8 $t1,$Xl,$Xh,#8 @ Karatsuba post-processing
	veor $t2,$Xl,$Xh
	veor $Xm,$Xm,$t1
	veor $Xm,$Xm,$t2
	vpmull.p64 $t2,$Xl,$xC2 @ 1st phase

	vmov $Xh#lo,$Xm#hi @ Xh\|Xm - 256-bit result
	vmov $Xm#hi,$Xl#lo @ Xm is rotated Xl
	veor $Xl,$Xm,$t2

	vext.8 $t2,$Xl,$Xl,#8 @ 2nd phase
	vpmull.p64 $Xl,$Xl,$xC2
	veor $t2,$t2,$Xh
	veor $H2,$Xl,$t2

	vext.8 $t1,$H2,$H2,#8 @ Karatsuba pre-processing
	veor $t1,$t1,$H2
	vext.8 $Hhl,$t0,$t1,#8 @ pack Karatsuba pre-processed
	vst1.64 {$Hhl-$H2},[x0] @ store Htable[1..2]

	ret
	.size gcm_init_v8,.-gcm_init_v8
	___
	################################################################################
	# void gcm_gmult_v8(u64 Xi[2],const u128 Htable[16]);
	#
	# input: Xi - current hash value;
	# Htable - table precomputed in gcm_init_v8;
	# output: Xi - next hash value Xi;
	#
	$code.=<<___;
	.global gcm_gmult_v8
	.type gcm_gmult_v8,%function
	.align 4
	gcm_gmult_v8:
	vld1.64 {$t1},[$Xi] @ load Xi
	vmov.i8 $xC2,#0xe1
	vld1.64 {$H-$Hhl},[$Htbl] @ load twisted H, ...
	vshl.u64 $xC2,$xC2,#57
	#ifndef __ARMEB__
	vrev64.8 $t1,$t1
	#endif
	vext.8 $IN,$t1,$t1,#8

	vpmull.p64 $Xl,$H,$IN @ H.lo·Xi.lo
	veor $t1,$t1,$IN @ Karatsuba pre-processing
	vpmull2.p64 $Xh,$H,$IN @ H.hi·Xi.hi
	vpmull.p64 $Xm,$Hhl,$t1 @ (H.lo+H.hi)·(Xi.lo+Xi.hi)

	vext.8 $t1,$Xl,$Xh,#8 @ Karatsuba post-processing
	veor $t2,$Xl,$Xh
	veor $Xm,$Xm,$t1
	veor $Xm,$Xm,$t2
	vpmull.p64 $t2,$Xl,$xC2 @ 1st phase of reduction

	vmov $Xh#lo,$Xm#hi @ Xh\|Xm - 256-bit result
	vmov $Xm#hi,$Xl#lo @ Xm is rotated Xl
	veor $Xl,$Xm,$t2

	vext.8 $t2,$Xl,$Xl,#8 @ 2nd phase of reduction
	vpmull.p64 $Xl,$Xl,$xC2
	veor $t2,$t2,$Xh
	veor $Xl,$Xl,$t2

	#ifndef __ARMEB__
	vrev64.8 $Xl,$Xl
	#endif
	vext.8 $Xl,$Xl,$Xl,#8
	vst1.64 {$Xl},[$Xi] @ write out Xi

	ret
	.size gcm_gmult_v8,.-gcm_gmult_v8
	___
	################################################################################
	# void gcm_ghash_v8(u64 Xi[2],const u128 Htable[16],const u8 *inp,size_t len);
	#
	# input: table precomputed in gcm_init_v8;
	# current hash value Xi;
	# pointer to input data;
	# length of input data in bytes, but divisible by block size;
	# output: next hash value Xi;
	#
	$code.=<<___;
	.global gcm_ghash_v8
	.type gcm_ghash_v8,%function
	.align 4
	gcm_ghash_v8:
	___
	$code.=<<___ if ($flavour !~ /64/);
	vstmdb sp!,{d8-d15} @ 32-bit ABI says so
	___
	$code.=<<___;
	vld1.64 {$Xl},[$Xi] @ load [rotated] Xi
	@ "[rotated]" means that
	@ loaded value would have
	@ to be rotated in order to
	@ make it appear as in
	@ alorithm specification
	subs $len,$len,#32 @ see if $len is 32 or larger
	mov $inc,#16 @ $inc is used as post-
	@ increment for input pointer;
	@ as loop is modulo-scheduled
	@ $inc is zeroed just in time
	@ to preclude oversteping
	@ inp[len], which means that
	@ last block[s] are actually
	@ loaded twice, but last
	@ copy is not processed
	vld1.64 {$H-$Hhl},[$Htbl],#32 @ load twisted H, ..., H^2
	vmov.i8 $xC2,#0xe1
	vld1.64 {$H2},[$Htbl]
	cclr $inc,eq @ is it time to zero $inc?
	vext.8 $Xl,$Xl,$Xl,#8 @ rotate Xi
	vld1.64 {$t0},[$inp],#16 @ load [rotated] I[0]
	vshl.u64 $xC2,$xC2,#57 @ compose 0xc2.0 constant
	#ifndef __ARMEB__
	vrev64.8 $t0,$t0
	vrev64.8 $Xl,$Xl
	#endif
	vext.8 $IN,$t0,$t0,#8 @ rotate I[0]
	b.lo .Lodd_tail_v8 @ $len was less than 32
	___
	{ my ($Xln,$Xmn,$Xhn,$In) = map("q$_",(4..7));
	#######
	# Xi+2 =[H*(Ii+1 + Xi+1)] mod P =
	# [(HIi+1) + (HXi+1)] mod P =
	# [(HIi+1) + H^2(Ii+Xi)] mod P
	#
	$code.=<<___;
	vld1.64 {$t1},[$inp],$inc @ load [rotated] I[1]
	#ifndef __ARMEB__
	vrev64.8 $t1,$t1
	#endif
	vext.8 $In,$t1,$t1,#8
	veor $IN,$IN,$Xl @ I[i]^=Xi
	vpmull.p64 $Xln,$H,$In @ H·Ii+1
	veor $t1,$t1,$In @ Karatsuba pre-processing
	vpmull2.p64 $Xhn,$H,$In
	b .Loop_mod2x_v8

	.align 4
	.Loop_mod2x_v8:
	vext.8 $t2,$IN,$IN,#8
	subs $len,$len,#32 @ is there more data?
	vpmull.p64 $Xl,$H2,$IN @ H^2.lo·Xi.lo
	cclr $inc,lo @ is it time to zero $inc?

	vpmull.p64 $Xmn,$Hhl,$t1
	veor $t2,$t2,$IN @ Karatsuba pre-processing
	vpmull2.p64 $Xh,$H2,$IN @ H^2.hi·Xi.hi
	veor $Xl,$Xl,$Xln @ accumulate
	vpmull2.p64 $Xm,$Hhl,$t2 @ (H^2.lo+H^2.hi)·(Xi.lo+Xi.hi)
	vld1.64 {$t0},[$inp],$inc @ load [rotated] I[i+2]

	veor $Xh,$Xh,$Xhn
	cclr $inc,eq @ is it time to zero $inc?
	veor $Xm,$Xm,$Xmn

	vext.8 $t1,$Xl,$Xh,#8 @ Karatsuba post-processing
	veor $t2,$Xl,$Xh
	veor $Xm,$Xm,$t1
	vld1.64 {$t1},[$inp],$inc @ load [rotated] I[i+3]
	#ifndef __ARMEB__
	vrev64.8 $t0,$t0
	#endif
	veor $Xm,$Xm,$t2
	vpmull.p64 $t2,$Xl,$xC2 @ 1st phase of reduction

	#ifndef __ARMEB__
	vrev64.8 $t1,$t1
	#endif
	vmov $Xh#lo,$Xm#hi @ Xh\|Xm - 256-bit result
	vmov $Xm#hi,$Xl#lo @ Xm is rotated Xl
	vext.8 $In,$t1,$t1,#8
	vext.8 $IN,$t0,$t0,#8
	veor $Xl,$Xm,$t2
	vpmull.p64 $Xln,$H,$In @ H·Ii+1
	veor $IN,$IN,$Xh @ accumulate $IN early

	vext.8 $t2,$Xl,$Xl,#8 @ 2nd phase of reduction
	vpmull.p64 $Xl,$Xl,$xC2
	veor $IN,$IN,$t2
	veor $t1,$t1,$In @ Karatsuba pre-processing
	veor $IN,$IN,$Xl
	vpmull2.p64 $Xhn,$H,$In
	b.hs .Loop_mod2x_v8 @ there was at least 32 more bytes

	veor $Xh,$Xh,$t2
	vext.8 $IN,$t0,$t0,#8 @ re-construct $IN
	adds $len,$len,#32 @ re-construct $len
	veor $Xl,$Xl,$Xh @ re-construct $Xl
	b.eq .Ldone_v8 @ is $len zero?
	___
	}
	$code.=<<___;
	.Lodd_tail_v8:
	vext.8 $t2,$Xl,$Xl,#8
	veor $IN,$IN,$Xl @ inp^=Xi
	veor $t1,$t0,$t2 @ $t1 is rotated inp^Xi

	vpmull.p64 $Xl,$H,$IN @ H.lo·Xi.lo
	veor $t1,$t1,$IN @ Karatsuba pre-processing
	vpmull2.p64 $Xh,$H,$IN @ H.hi·Xi.hi
	vpmull.p64 $Xm,$Hhl,$t1 @ (H.lo+H.hi)·(Xi.lo+Xi.hi)

	vext.8 $t1,$Xl,$Xh,#8 @ Karatsuba post-processing
	veor $t2,$Xl,$Xh
	veor $Xm,$Xm,$t1
	veor $Xm,$Xm,$t2
	vpmull.p64 $t2,$Xl,$xC2 @ 1st phase of reduction

	vmov $Xh#lo,$Xm#hi @ Xh\|Xm - 256-bit result
	vmov $Xm#hi,$Xl#lo @ Xm is rotated Xl
	veor $Xl,$Xm,$t2

	vext.8 $t2,$Xl,$Xl,#8 @ 2nd phase of reduction
	vpmull.p64 $Xl,$Xl,$xC2
	veor $t2,$t2,$Xh
	veor $Xl,$Xl,$t2

	.Ldone_v8:
	#ifndef __ARMEB__
	vrev64.8 $Xl,$Xl
	#endif
	vext.8 $Xl,$Xl,$Xl,#8
	vst1.64 {$Xl},[$Xi] @ write out Xi

	___
	$code.=<<___ if ($flavour !~ /64/);
	vldmia sp!,{d8-d15} @ 32-bit ABI says so
	___
	$code.=<<___;
	ret
	.size gcm_ghash_v8,.-gcm_ghash_v8
	___
	}
	$code.=<<___;
	.asciz "GHASH for ARMv8, CRYPTOGAMS by <appro\@openssl.org>"
	.align 2
	___

	if ($flavour =~ /64/) { ######## 64-bit code
	sub unvmov {
	my $arg=shift;

	$arg =~ m/q([0-9]+)#(lo\|hi),\s*q([0-9]+)#(lo\|hi)/o &&
	sprintf "ins v%d.d[%d],v%d.d[%d]",$1,($2 eq "lo")?0:1,$3,($4 eq "lo")?0:1;
	}
	foreach(split("\n",$code)) {
	s/cclr\s+([wx])([^,]+),\s*([a-z]+)/csel $1$2,$1zr,$1$2,$3/o or
	s/vmov\.i8/movi/o or # fix up legacy mnemonics
	s/vmov\s+(.*)/unvmov($1)/geo or
	s/vext\.8/ext/o or
	s/vshr\.s/sshr\.s/o or
	s/vshr/ushr/o or
	s/^(\s+)v/$1/o or # strip off v prefix
	s/\bbx\s+lr\b/ret/o;

	s/\bq([0-9]+)\b/"v".($1<8?$1:$1+8).".16b"/geo; # old->new registers
	s/@\s/\/\//o; # old->new style commentary

	# fix up remainig legacy suffixes
	s/\.[ui]?8(\s)/$1/o;
	s/\.[uis]?32//o and s/\.16b/\.4s/go;
	m/\.p64/o and s/\.16b/\.1q/o; # 1st pmull argument
	m/l\.p64/o and s/\.16b/\.1d/go; # 2nd and 3rd pmull arguments
	s/\.[uisp]?64//o and s/\.16b/\.2d/go;
	s/\.[42]([sd])\[([0-3])\]/\.$1\[$2\]/o;

	print $_,"\n";
	}
	} else { ######## 32-bit code
	sub unvdup32 {
	my $arg=shift;

	$arg =~ m/q([0-9]+),\s*q([0-9]+)\[([0-3])\]/o &&
	sprintf "vdup.32 q%d,d%d[%d]",$1,2*$2+($3>>1),$3&1;
	}
	sub unvpmullp64 {
	my ($mnemonic,$arg)=@_;

	if ($arg =~ m/q([0-9]+),\sq([0-9]+),\sq([0-9]+)/o) {
	my $word = 0xf2a00e00\|(($1&7)<<13)\|(($1&8)<<19)
	\|(($2&7)<<17)\|(($2&8)<<4)
	\|(($3&7)<<1) \|(($3&8)<<2);
	$word \|= 0x00010001 if ($mnemonic =~ "2");
	# since ARMv7 instructions are always encoded little-endian.
	# correct solution is to use .inst directive, but older
	# assemblers don't implement it:-(
	sprintf ".byte\t0x%02x,0x%02x,0x%02x,0x%02x\t@ %s %s",
	$word&0xff,($word>>8)&0xff,
	($word>>16)&0xff,($word>>24)&0xff,
	$mnemonic,$arg;
	}
	}

	foreach(split("\n",$code)) {
	s/\b[wx]([0-9]+)\b/r$1/go; # new->old registers
	s/\bv([0-9])\.[12468]+[bsd]\b/q$1/go; # new->old registers
	s/\/\/\s?/@ /o; # new->old style commentary

	# fix up remainig new-style suffixes
	s/\],#[0-9]+/]!/o;

	s/cclr\s+([^,]+),\s*([a-z]+)/mov$2 $1,#0/o or
	s/vdup\.32\s+(.*)/unvdup32($1)/geo or
	s/v?(pmull2?)\.p64\s+(.*)/unvpmullp64($1,$2)/geo or
	s/\bq([0-9]+)#(lo\|hi)/sprintf "d%d",2*$1+($2 eq "hi")/geo or
	s/^(\s+)b\./$1b/o or
	s/^(\s+)ret/$1bx\tlr/o;

	print $_,"\n";
	}
	}

	close STDOUT; # enforce flush