dnl  AMD64 mpn_cnd_add_n, mpn_cnd_sub_n

dnl  Copyright 2011-2013 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 AMD K8,K9	 2

C AMD K10	 2

C AMD bd1	 2.32

C AMD bobcat	 3

C Intel P4	13

C Intel core2	 2.9

C Intel NHM	 2.8

C Intel SBR	 2.4

C Intel atom	 5.33

C VIA nano	 3

C NOTES

C  * It might seem natural to use the cmov insn here, but since this function

C    is supposed to have the exact same execution pattern for cnd true and

C    false, and since cmov's documentation is not clear about whether it

C    actually reads both source operands and writes the register for a false

C    condition, we cannot use it.

C  * Two cases could be optimised: (1) cnd_add_n could use ADCSBB-from-memory

C    to save one insn/limb, and (2) when up=rp cnd_add_n and cnd_sub_n could use

C    ADCSBB-to-memory, again saving 1 insn/limb.

C  * This runs optimally at decoder bandwidth on K10.  It has not been tuned

C    for any other processor.

C INPUT PARAMETERS

define(`cnd',	`%rdi')	dnl rcx

define(`rp',	`%rsi')	dnl rdx

define(`up',	`%rdx')	dnl r8

define(`vp',	`%rcx')	dnl r9

define(`n',	`%r8')	dnl rsp+40

ifdef(`OPERATION_cnd_add_n', `

	define(ADDSUB,	      add)

	define(ADCSBB,	      adc)

	define(func,	      mpn_cnd_add_n)')

ifdef(`OPERATION_cnd_sub_n', `

	define(ADDSUB,	      sub)

	define(ADCSBB,	      sbb)

	define(func,	      mpn_cnd_sub_n)')

MULFUNC_PROLOGUE(mpn_cnd_add_n mpn_cnd_sub_n)

ABI_SUPPORT(DOS64)

ABI_SUPPORT(STD64)

ASM_START()

	TEXT

	ALIGN(16)

PROLOGUE(func)

	FUNC_ENTRY(4)

IFDOS(`	mov	56(%rsp), R32(%r8)')

	push	%rbx

	push	%rbp

	push	%r12

	push	%r13

	push	%r14

	neg	cnd

	sbb	cnd, cnd		C make cnd mask

	lea	(vp,n,8), vp

	lea	(up,n,8), up

	lea	(rp,n,8), rp

	mov	R32(n), R32(%rax)

	neg	n

	and	$3, R32(%rax)

	jz	L(top)			C carry-save reg rax = 0 in this arc

	cmp	$2, R32(%rax)

	jc	L(b1)

	jz	L(b2)

L(b3):	mov	(vp,n,8), %r12

	mov	8(vp,n,8), %r13

	mov	16(vp,n,8), %r14

	and	cnd, %r12

	mov	(up,n,8), %r10

	and	cnd, %r13

	mov	8(up,n,8), %rbx

	and	cnd, %r14

	mov	16(up,n,8), %rbp

	ADDSUB	%r12, %r10

	mov	%r10, (rp,n,8)

	ADCSBB	%r13, %rbx

	mov	%rbx, 8(rp,n,8)

	ADCSBB	%r14, %rbp

	mov	%rbp, 16(rp,n,8)

	sbb	R32(%rax), R32(%rax)	C save carry

	add	$3, n

	js	L(top)

	jmp	L(end)

L(b2):	mov	(vp,n,8), %r12

	mov	8(vp,n,8), %r13

	mov	(up,n,8), %r10

	and	cnd, %r12

	mov	8(up,n,8), %rbx

	and	cnd, %r13

	ADDSUB	%r12, %r10

	mov	%r10, (rp,n,8)

	ADCSBB	%r13, %rbx

	mov	%rbx, 8(rp,n,8)

	sbb	R32(%rax), R32(%rax)	C save carry

	add	$2, n

	js	L(top)

	jmp	L(end)

L(b1):	mov	(vp,n,8), %r12

	mov	(up,n,8), %r10

	and	cnd, %r12

	ADDSUB	%r12, %r10

	mov	%r10, (rp,n,8)

	sbb	R32(%rax), R32(%rax)	C save carry

	add	$1, n

	jns	L(end)

	ALIGN(16)

L(top):	mov	(vp,n,8), %r12

	mov	8(vp,n,8), %r13

	mov	16(vp,n,8), %r14

	mov	24(vp,n,8), %r11

	and	cnd, %r12

	mov	(up,n,8), %r10

	and	cnd, %r13

	mov	8(up,n,8), %rbx

	and	cnd, %r14

	mov	16(up,n,8), %rbp

	and	cnd, %r11

	mov	24(up,n,8), %r9

	add	R32(%rax), R32(%rax)	C restore carry

	ADCSBB	%r12, %r10

	mov	%r10, (rp,n,8)

	ADCSBB	%r13, %rbx

	mov	%rbx, 8(rp,n,8)

	ADCSBB	%r14, %rbp

	mov	%rbp, 16(rp,n,8)

	ADCSBB	%r11, %r9

	mov	%r9, 24(rp,n,8)

	sbb	R32(%rax), R32(%rax)	C save carry

	add	$4, n

	js	L(top)

L(end):	neg	R32(%rax)

	pop	%r14

	pop	%r13

	pop	%r12

	pop	%rbp

	pop	%rbx

	FUNC_EXIT()

	ret

EPILOGUE()

CF_PROT