#! /usr/bin/env perl

# Copyright 2007-2020 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/.

# ====================================================================

# sha1_block for Thumb.

#

# January 2007.

#

# The code does not present direct interest to OpenSSL, because of low

# performance. Its purpose is to establish _size_ benchmark. Pretty

# useless one I must say, because 30% or 88 bytes larger ARMv4 code

# [available on demand] is almost _twice_ as fast. It should also be

# noted that in-lining of .Lcommon and .Lrotate improves performance

# by over 40%, while code increases by only 10% or 32 bytes. But once

# again, the goal was to establish _size_ benchmark, not performance.

$output=shift;

open STDOUT,">$output";

$inline=0;

#$cheat_on_binutils=1;

$t0="r0";

$t1="r1";

$t2="r2";

$a="r3";

$b="r4";

$c="r5";

$d="r6";

$e="r7";

$K="r8";	# "upper" registers can be used in add/sub and mov insns

$ctx="r9";

$inp="r10";

$len="r11";

$Xi="r12";

sub common {

<<___;

	sub	$t0,#4

	ldr	$t1,[$t0]

	add	$e,$K			@ E+=K_xx_xx

	lsl	$t2,$a,#5

	add	$t2,$e

	lsr	$e,$a,#27

	add	$t2,$e			@ E+=ROR(A,27)

	add	$t2,$t1			@ E+=X[i]

___

}

sub rotate {

<<___;

	mov	$e,$d			@ E=D

	mov	$d,$c			@ D=C

	lsl	$c,$b,#30

	lsr	$b,$b,#2

	orr	$c,$b			@ C=ROR(B,2)

	mov	$b,$a			@ B=A

	add	$a,$t2,$t1		@ A=E+F_xx_xx(B,C,D)

___

}

sub BODY_00_19 {

$code.=$inline?&common():"\tbl	.Lcommon\n";

$code.=<<___;

	mov	$t1,$c

	eor	$t1,$d

	and	$t1,$b

	eor	$t1,$d			@ F_00_19(B,C,D)

___

$code.=$inline?&rotate():"\tbl	.Lrotate\n";

}

sub BODY_20_39 {

$code.=$inline?&common():"\tbl	.Lcommon\n";

$code.=<<___;

	mov	$t1,$b

	eor	$t1,$c

	eor	$t1,$d			@ F_20_39(B,C,D)

___

$code.=$inline?&rotate():"\tbl	.Lrotate\n";

}

sub BODY_40_59 {

$code.=$inline?&common():"\tbl	.Lcommon\n";

$code.=<<___;

	mov	$t1,$b

	and	$t1,$c

	mov	$e,$b

	orr	$e,$c

	and	$e,$d

	orr	$t1,$e			@ F_40_59(B,C,D)

___

$code.=$inline?&rotate():"\tbl	.Lrotate\n";

}

$code=<<___;

.text

.code	16

.global	sha1_block_data_order

.type	sha1_block_data_order,%function

.align	2

sha1_block_data_order:

___

if ($cheat_on_binutils) {

$code.=<<___;

.code	32

	add	r3,pc,#1

	bx	r3			@ switch to Thumb ISA

.code	16

___

}

$code.=<<___;

	push	{r4-r7}

	mov	r3,r8

	mov	r4,r9

	mov	r5,r10

	mov	r6,r11

	mov	r7,r12

	push	{r3-r7,lr}

	lsl	r2,#6

	mov	$ctx,r0			@ save context

	mov	$inp,r1			@ save inp

	mov	$len,r2			@ save len

	add	$len,$inp		@ $len to point at inp end

.Lloop:

	mov	$Xi,sp

	mov	$t2,sp

	sub	$t2,#16*4		@ [3]

.LXload:

	ldrb	$a,[$t1,#0]		@ $t1 is r1 and holds inp

	ldrb	$b,[$t1,#1]

	ldrb	$c,[$t1,#2]

	ldrb	$d,[$t1,#3]

	lsl	$a,#24

	lsl	$b,#16

	lsl	$c,#8

	orr	$a,$b

	orr	$a,$c

	orr	$a,$d

	add	$t1,#4

	push	{$a}

	cmp	sp,$t2

	bne	.LXload			@ [+14*16]

	mov	$inp,$t1		@ update $inp

	sub	$t2,#32*4

	sub	$t2,#32*4

	mov	$e,#31			@ [+4]

.LXupdate:

	ldr	$a,[sp,#15*4]

	ldr	$b,[sp,#13*4]

	ldr	$c,[sp,#7*4]

	ldr	$d,[sp,#2*4]

	eor	$a,$b

	eor	$a,$c

	eor	$a,$d

	ror	$a,$e

	push	{$a}

	cmp	sp,$t2

	bne	.LXupdate		@ [+(11+1)*64]

	ldmia	$t0!,{$a,$b,$c,$d,$e}	@ $t0 is r0 and holds ctx

	mov	$t0,$Xi

	ldr	$t2,.LK_00_19

	mov	$t1,$t0

	sub	$t1,#20*4

	mov	$Xi,$t1

	mov	$K,$t2			@ [+7+4]

.L_00_19:

___

	&BODY_00_19();

$code.=<<___;

	cmp	$Xi,$t0

	bne	.L_00_19		@ [+(2+9+4+2+8+2)*20]

	ldr	$t2,.LK_20_39

	mov	$t1,$t0

	sub	$t1,#20*4

	mov	$Xi,$t1

	mov	$K,$t2			@ [+5]

.L_20_39_or_60_79:

___

	&BODY_20_39();

$code.=<<___;

	cmp	$Xi,$t0

	bne	.L_20_39_or_60_79	@ [+(2+9+3+2+8+2)*20*2]

	cmp	sp,$t0

	beq	.Ldone			@ [+2]

	ldr	$t2,.LK_40_59

	mov	$t1,$t0

	sub	$t1,#20*4

	mov	$Xi,$t1

	mov	$K,$t2			@ [+5]

.L_40_59:

___

	&BODY_40_59();

$code.=<<___;

	cmp	$Xi,$t0

	bne	.L_40_59		@ [+(2+9+6+2+8+2)*20]

	ldr	$t2,.LK_60_79

	mov	$Xi,sp

	mov	$K,$t2

	b	.L_20_39_or_60_79	@ [+4]

.Ldone:

	mov	$t0,$ctx

	ldr	$t1,[$t0,#0]

	ldr	$t2,[$t0,#4]

	add	$a,$t1

	ldr	$t1,[$t0,#8]

	add	$b,$t2

	ldr	$t2,[$t0,#12]

	add	$c,$t1

	ldr	$t1,[$t0,#16]

	add	$d,$t2

	add	$e,$t1

	stmia	$t0!,{$a,$b,$c,$d,$e}	@ [+20]

	add	sp,#80*4		@ deallocate stack frame

	mov	$t0,$ctx		@ restore ctx

	mov	$t1,$inp		@ restore inp

	cmp	$t1,$len

	beq	.Lexit

	b	.Lloop			@ [+6] total 3212 cycles

.Lexit:

	pop	{r2-r7}

	mov	r8,r2

	mov	r9,r3

	mov	r10,r4

	mov	r11,r5

	mov	r12,r6

	mov	lr,r7

	pop	{r4-r7}

	bx	lr

.align	2

___

$code.=".Lcommon:\n".&common()."\tmov	pc,lr\n" if (!$inline);

$code.=".Lrotate:\n".&rotate()."\tmov	pc,lr\n" if (!$inline);

$code.=<<___;

.align	2

.LK_00_19:	.word	0x5a827999

.LK_20_39:	.word	0x6ed9eba1

.LK_40_59:	.word	0x8f1bbcdc

.LK_60_79:	.word	0xca62c1d6

.size	sha1_block_data_order,.-sha1_block_data_order

.asciz	"SHA1 block transform for Thumb, CRYPTOGAMS by <appro\@openssl.org>"

___

print $code;

close STDOUT or die "error closing STDOUT: $!"; # enforce flush