/* AMD64 (x86_64) rshift -- Right shift a limb vector and store
* result in a second limb vector.
*
* Copyright (C) 1992, 1994, 1995, 1998,
* 2001, 2002, 2006 Free Software Foundation, Inc.
*
* This file is part of Libgcrypt.
*
* Libgcrypt is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* Libgcrypt is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*
* Note: This code is heavily based on the GNU MP Library.
* Actually it's the same code with only minor changes in the
* way the data is stored; this is to support the abstraction
* of an optional secure memory allocation which may be used
* to avoid revealing of sensitive data due to paging etc.
*/
#include "sysdep.h"
#include "asm-syntax.h"
/*******************
* mpi_limb_t
* _gcry_mpih_rshift( mpi_ptr_t wp, rdi
* mpi_ptr_t up, rsi
* mpi_size_t usize, rdx
* unsigned cnt) rcx
*/
.text
.globl C_SYMBOL_NAME(_gcry_mpih_rshift)
C_SYMBOL_NAME(_gcry_mpih_rshift:)
FUNC_ENTRY()
movq (%rsi), %mm7
movd %ecx, %mm1
movl $64, %eax
subl %ecx, %eax
movd %eax, %mm0
movq %mm7, %mm3
psllq %mm0, %mm7
movd %mm7, %rax
leaq (%rsi,%rdx,8), %rsi
leaq (%rdi,%rdx,8), %rdi
negq %rdx
addq $2, %rdx
jg .Lendo
ALIGN(4) /* minimal alignment for claimed speed */
.Loop: movq -8(%rsi,%rdx,8), %mm6
movq %mm6, %mm2
psllq %mm0, %mm6
psrlq %mm1, %mm3
por %mm6, %mm3
movq %mm3, -16(%rdi,%rdx,8)
je .Lende
movq (%rsi,%rdx,8), %mm7
movq %mm7, %mm3
psllq %mm0, %mm7
psrlq %mm1, %mm2
por %mm7, %mm2
movq %mm2, -8(%rdi,%rdx,8)
addq $2, %rdx
jle .Loop
.Lendo: movq %mm3, %mm2
.Lende: psrlq %mm1, %mm2
movq %mm2, -8(%rdi)
emms
FUNC_EXIT()
ret
