mpir/mpn/x86w/rshift.asm
brgladman 9c467c6415
2008-07-04 10:39:15 +00:00

89 lines
2.3 KiB
NASM

; Copyright 1992, 1994, 1996, 1999, 2000, 2001, 2002 Free Software
; Foundation, Inc.
;
; This file is part of the GNU MP Library.
;
; The GNU MP Library 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.
;
; The GNU MP Library 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 the GNU MP Library; see the file COPYING.LIB. If
; not, write to the Free Software Foundation, Inc., 59 Temple Place -
; Suite 330, Boston, MA 02111-1307, USA.
;
; Translation of AT&T syntax code by Brian Gladman
%include "x86i.inc"
%define PARAM_SHIFT esp+frame+16
%define PARAM_SIZE esp+frame+12
%define PARAM_SRC esp+frame+8
%define PARAM_DST esp+frame+4
%assign frame frame+12
section .text
global ___gmpn_rshift
%ifdef DLL
export ___gmpn_rshift
%endif
align 8
___gmpn_rshift:
push edi
push esi
push ebx
mov edi,[PARAM_DST]
mov esi,[PARAM_SRC]
mov edx,[PARAM_SIZE]
mov ecx,[PARAM_SHIFT]
lea edi,[-4+edi+edx*4]
lea esi,[esi+edx*4]
neg edx
mov ebx,[esi+edx*4] ; read least significant limb
xor eax,eax
shrd eax,ebx,cl
inc edx
jz Lend
push eax ; push carry limb onto stack
test dl,1
jnz L1 ; enter Lop in the middle
mov eax,ebx
align 8
Lop:
mov ebx,[esi+edx*4] ; load next higher limb
shrd eax,ebx,cl
mov [edi+edx*4],eax ; store it
inc edx
L1:
mov eax,[esi+edx*4]
shrd ebx,eax,cl
mov [edi+edx*4],ebx
inc edx
jnz Lop
shr eax,cl ; compute most significant limb
mov [edi],eax ; store it
pop eax ; pop carry limb
pop ebx
pop esi
pop edi
ret
Lend:
shr ebx,cl ; compute most significant limb
mov [edi],ebx ; store it
pop ebx
pop esi
pop edi
ret
end