dnl  x86-64 mpn_rshift optimized for Pentium 4.

dnl  Copyright 2003, 2005, 2007, 2008, 2012 Free Software Foundation, Inc.

dnl  This file is part of the GNU MP Library.

dnl  The GNU MP Library is free software; you can redistribute it and/or modify
dnl  it under the terms of the GNU Lesser General Public License as published
dnl  by the Free Software Foundation; either version 3 of the License, or (at
dnl  your option) any later version.

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 Lesser General Public
dnl  License for more details.

dnl  You should have received a copy of the GNU Lesser General Public License
dnl  along with the GNU MP Library.  If not, see http://www.gnu.org/licenses/.

include(`../config.m4')


C	     cycles/limb
C AMD K8,K9	 2.5
C AMD K10	 ?
C Intel P4	 3.29
C Intel core2	 2.1 (fluctuates, presumably cache related)
C Intel corei	 ?
C Intel atom	14.3
C VIA nano	 ?

C INPUT PARAMETERS
define(`rp',`%rdi')
define(`up',`%rsi')
define(`n',`%rdx')
define(`cnt',`%cl')

ABI_SUPPORT(DOS64)
ABI_SUPPORT(STD64)

ASM_START()
	TEXT
	ALIGN(32)
PROLOGUE(mpn_rshift)
	FUNC_ENTRY(4)
	mov	(up), %rax
	movd	R32(%rcx), %mm4
	neg	R32(%rcx)			C put lsh count in cl
	and	$63, R32(%rcx)
	movd	R32(%rcx), %mm5

	lea	-8(up,n,8), up
	lea	-8(rp,n,8), rp
	lea	1(n), R32(%r8)
	neg	n

	shl	R8(%rcx), %rax		C function return value

	and	$3, R32(%r8)
	je	L(rol)			C jump for n = 3, 7, 11, ...

	dec	R32(%r8)
	jne	L(1)
C	n = 4, 8, 12, ...
	movq	8(up,n,8), %mm2
	psrlq	%mm4, %mm2
	movq	16(up,n,8), %mm0
	psllq	%mm5, %mm0
	por	%mm0, %mm2
	movq	%mm2, 8(rp,n,8)
	inc	n
	jmp	L(rol)

L(1):	dec	R32(%r8)
	je	L(1x)			C jump for n = 1, 5, 9, 13, ...
C	n = 2, 6, 10, 16, ...
	movq	8(up,n,8), %mm2
	psrlq	%mm4, %mm2
	movq	16(up,n,8), %mm0
	psllq	%mm5, %mm0
	por	%mm0, %mm2
	movq	%mm2, 8(rp,n,8)
	inc	n
L(1x):
	cmp	$-1, n
	je	L(ast)
	movq	8(up,n,8), %mm2
	psrlq	%mm4, %mm2
	movq	16(up,n,8), %mm3
	psrlq	%mm4, %mm3
	movq	16(up,n,8), %mm0
	movq	24(up,n,8), %mm1
	psllq	%mm5, %mm0
	por	%mm0, %mm2
	psllq	%mm5, %mm1
	por	%mm1, %mm3
	movq	%mm2, 8(rp,n,8)
	movq	%mm3, 16(rp,n,8)
	add	$2, n

L(rol):	movq	8(up,n,8), %mm2
	psrlq	%mm4, %mm2
	movq	16(up,n,8), %mm3
	psrlq	%mm4, %mm3

	add	$4, n			C				      4
	jb	L(end)			C				      2
	ALIGN(32)
L(top):
	C finish stuff from lsh block
	movq	-16(up,n,8), %mm0
	movq	-8(up,n,8), %mm1
	psllq	%mm5, %mm0
	por	%mm0, %mm2
	psllq	%mm5, %mm1
	movq	(up,n,8), %mm0
	por	%mm1, %mm3
	movq	8(up,n,8), %mm1
	movq	%mm2, -24(rp,n,8)
	movq	%mm3, -16(rp,n,8)
	C start two new rsh
	psllq	%mm5, %mm0
	psllq	%mm5, %mm1

	C finish stuff from rsh block
	movq	-8(up,n,8), %mm2
	movq	(up,n,8), %mm3
	psrlq	%mm4, %mm2
	por	%mm2, %mm0
	psrlq	%mm4, %mm3
	movq	8(up,n,8), %mm2
	por	%mm3, %mm1
	movq	16(up,n,8), %mm3
	movq	%mm0, -8(rp,n,8)
	movq	%mm1, (rp,n,8)
	C start two new lsh
	add	$4, n
	psrlq	%mm4, %mm2
	psrlq	%mm4, %mm3

	jae	L(top)			C				      2
L(end):
	movq	-8(up), %mm0
	psllq	%mm5, %mm0
	por	%mm0, %mm2
	movq	(up), %mm1
	psllq	%mm5, %mm1
	por	%mm1, %mm3
	movq	%mm2, -16(rp)
	movq	%mm3, -8(rp)

L(ast):	movq	(up), %mm2
	psrlq	%mm4, %mm2
	movq	%mm2, (rp)
	emms
	FUNC_EXIT()
	ret
EPILOGUE()
