dnl  AMD K7 mpn_mod_34lsub1 -- remainder modulo 2^24-1.

dnl  Copyright 2000-2002, 2004, 2005, 2008 Free Software Foundation, Inc.

dnl  This file is part of the GNU MP Library.

dnl

dnl  The GNU MP Library is free software; you can redistribute it and/or modify

dnl  it under the terms of either:

dnl

dnl    * the GNU Lesser General Public License as published by the Free

dnl      Software Foundation; either version 3 of the License, or (at your

dnl      option) any later version.

dnl

dnl  or

dnl

dnl    * the GNU General Public License as published by the Free Software

dnl      Foundation; either version 2 of the License, or (at your option) any

dnl      later version.

dnl

dnl  or both in parallel, as here.

dnl

dnl  The GNU MP Library is distributed in the hope that it will be useful, but

dnl  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY

dnl  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

dnl  for more details.

dnl

dnl  You should have received copies of the GNU General Public License and the

dnl  GNU Lesser General Public License along with the GNU MP Library.  If not,

dnl  see https://www.gnu.org/licenses/.

include(`../config.m4')

C         cycles/limb

C Athlon:     1

C Hammer:     1

C mp_limb_t mpn_mod_34lsub1 (mp_srcptr src, mp_size_t size)

C

C The loop form below and the 64 byte code alignment seem necessary for the

C claimed speed.  This is a bit strange, since normally k7 isn't very

C sensitive to such things.  Perhaps there has to be 6 instructions in the

C first 16 bytes for the BTB entry or something.

defframe(PARAM_SIZE, 8)

defframe(PARAM_SRC,  4)

dnl  re-use parameter space

define(SAVE_EDI, `PARAM_SIZE')

	TEXT

	ALIGN(64)

PROLOGUE(mpn_mod_34lsub1)

deflit(`FRAME',0)

	movl	PARAM_SIZE, %ecx

	movl	PARAM_SRC, %edx

	subl	$2, %ecx

	ja	L(three_or_more)

	movl	(%edx), %eax

	jb	L(one)

	movl	4(%edx), %ecx

	movl	%eax, %edx

	shrl	$24, %eax		C src[0] low

	andl	$0xFFFFFF, %edx		C src[0] high

	addl	%edx, %eax

	movl	%ecx, %edx

	andl	$0xFFFF, %ecx

	shrl	$16, %edx		C src[1] high

	addl	%edx, %eax

	shll	$8, %ecx		C src[1] low

	addl	%ecx, %eax

L(one):

	ret

L(three_or_more):

	C eax

	C ebx

	C ecx	size-2

	C edx	src

	C esi

	C edi

	pushl	%ebx	FRAME_pushl()

	xorl	%eax, %eax

	xorl	%ebx, %ebx

	movl	%edi, SAVE_EDI

	pushl	%esi	FRAME_pushl()

	xorl	%esi, %esi		C and clear carry flag

	C code offset 0x40 at this point

L(top):

	C eax	acc 0mod3

	C ebx	acc 1mod3

	C ecx	counter, limbs

	C edx	src

	C esi	acc 2mod3

	C edi

	leal	24(%edx), %edx

	leal	-2(%ecx), %ecx

	adcl	-24(%edx), %eax

	adcl	-20(%edx), %ebx

	adcl	-16(%edx), %esi

	decl	%ecx

	jng	L(done_loop)

	leal	-2(%ecx), %ecx

	adcl	-12(%edx), %eax

	adcl	-8(%edx), %ebx

	adcl	-4(%edx), %esi

	decl	%ecx

	jg	L(top)

	leal	12(%edx), %edx

L(done_loop):

	C ecx is -2, -1 or 0 representing 0, 1 or 2 more limbs, respectively

	incl	%ecx

	movl	$0xFFFFFFFF, %edi

	js	L(combine)

	adcl	-12(%edx), %eax

	decl	%ecx

	movl	$0xFFFFFF00, %edi

	js	L(combine)

	adcl	-8(%edx), %ebx

	movl	$0xFFFF0000, %edi

L(combine):

	C eax	acc 0mod3

	C ebx	acc 1mod3

	C ecx

	C edx

	C esi	acc 2mod3

	C edi	mask

	sbbl	%ecx, %ecx		C carry

	movl	%eax, %edx		C 0mod3

	shrl	$24, %eax		C 0mod3 high

	andl	%edi, %ecx		C carry masked

	andl	$0x00FFFFFF, %edx	C 0mod3 low

	movl	%ebx, %edi		C 1mod3

	subl	%ecx, %eax		C apply carry

	shrl	$16, %ebx		C 1mod3 high

	andl	$0xFFFF, %edi

	addl	%edx, %eax		C apply 0mod3 low

	movl	%esi, %edx		C 2mod3

	shll	$8, %edi		C 1mod3 low

	addl	%ebx, %eax		C apply 1mod3 high

	shrl	$8, %esi		C 2mod3 high

	movzbl	%dl, %edx		C 2mod3 low

	addl	%edi, %eax		C apply 1mod3 low

	shll	$16, %edx		C 2mod3 low

	addl	%esi, %eax		C apply 2mod3 high

	popl	%esi	FRAME_popl()

	movl	SAVE_EDI, %edi

	addl	%edx, %eax		C apply 2mod3 low

	popl	%ebx	FRAME_popl()

	ret

EPILOGUE()