aboutsummaryrefslogtreecommitdiff
path: root/sysdeps/i386/lshift.S
blob: 737ce3ed2bed24a0b4bc4dd52003dbf95ef80335 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
/* i80386 __mpn_lshift --
   Copyright (C) 1992, 1994, 1997, 1998, 1999 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 Library General Public License as published by
   the Free Software Foundation; either version 2 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 Library General Public
   License for more details.

   You should have received a copy of the GNU Library 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. */

/*
  INPUT PARAMETERS
  res_ptr	(sp + 4)
  s_ptr		(sp + 8)
  size		(sp + 12)
  cnt		(sp + 16)
*/

#include "sysdep.h"
#include "asm-syntax.h"

	.text
ENTRY(__mpn_lshift)
	pushl	%edi
	pushl	%esi
	pushl	%ebx

	movl	16(%esp),%edi		/* res_ptr */
	movl	20(%esp),%esi		/* s_ptr */
	movl	24(%esp),%edx		/* size */
	movl	28(%esp),%ecx		/* cnt */

	subl	$4,%esi			/* adjust s_ptr */

	movl	(%esi,%edx,4),%ebx	/* read most significant limb */
	xorl	%eax,%eax
	shldl	%cl,%ebx,%eax		/* compute carry limb */
	decl	%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 lower limb */
	shldl	%cl,%ebx,%eax		/* compute result limb */
	movl	%eax,(%edi,%edx,4)	/* store it */
	decl	%edx
L(1):	movl	(%esi,%edx,4),%eax
	shldl	%cl,%eax,%ebx
	movl	%ebx,(%edi,%edx,4)
	decl	%edx
	jnz	L(oop)

	shll	%cl,%eax		/* compute least significant limb */
	movl	%eax,(%edi)		/* store it */

	popl	%eax			/* pop carry limb */

	popl	%ebx
	popl	%esi
	popl	%edi
	ret

L(end):	shll	%cl,%ebx		/* compute least significant limb */
	movl	%ebx,(%edi)		/* store it */

	popl	%ebx
	popl	%esi
	popl	%edi
	ret
END(__mpn_lshift)