glibc/sysdeps/i386/rshift.S
2001-07-07 10:13:33 +00:00

96 lines
2.4 KiB
ArmAsm

/* i80386 __mpn_rshift --
Copyright (C) 1992, 1994, 1997, 1998, 1999, 2000 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. */
#include "sysdep.h"
#include "asm-syntax.h"
#include "bp-sym.h"
#include "bp-asm.h"
#define PARMS LINKAGE+12 /* space for 3 saved regs */
#define RES PARMS
#define S RES+PTR_SIZE
#define SIZE S+PTR_SIZE
#define CNT SIZE+4
.text
ENTRY (BP_SYM (__mpn_rshift))
ENTER
pushl %edi
pushl %esi
pushl %ebx
movl RES(%esp),%edi
movl S(%esp),%esi
movl SIZE(%esp),%edx
movl CNT(%esp),%ecx
#if __BOUNDED_POINTERS__
shll $2, %edx /* convert limbs to bytes */
CHECK_BOUNDS_BOTH_WIDE (%edi, RES(%esp), %edx)
CHECK_BOUNDS_BOTH_WIDE (%esi, S(%esp), %edx)
shrl $2, %edx
#endif
leal -4(%edi,%edx,4),%edi
leal (%esi,%edx,4),%esi
negl %edx
movl (%esi,%edx,4),%ebx /* read least significant limb */
xorl %eax,%eax
shrdl %cl,%ebx,%eax /* compute carry limb */
incl %edx
jz L(end)
pushl %eax /* push carry limb onto stack */
testb $1,%dl
jnz L(1) /* enter loop in the middle */
movl %ebx,%eax
ALIGN (3)
L(oop): movl (%esi,%edx,4),%ebx /* load next higher limb */
shrdl %cl,%ebx,%eax /* compute result limb */
movl %eax,(%edi,%edx,4) /* store it */
incl %edx
L(1): movl (%esi,%edx,4),%eax
shrdl %cl,%eax,%ebx
movl %ebx,(%edi,%edx,4)
incl %edx
jnz L(oop)
shrl %cl,%eax /* compute most significant limb */
movl %eax,(%edi) /* store it */
popl %eax /* pop carry limb */
popl %ebx
popl %esi
popl %edi
LEAVE
ret
L(end): shrl %cl,%ebx /* compute most significant limb */
movl %ebx,(%edi) /* store it */
popl %ebx
popl %esi
popl %edi
LEAVE
ret
END (BP_SYM (__mpn_rshift))