1/* i80386 __mpn_lshift --
2 Copyright (C) 1992-2022 Free Software Foundation, Inc.
3 This file is part of the GNU MP Library.
4
5 The GNU MP Library is free software; you can redistribute it and/or modify
6 it under the terms of the GNU Lesser General Public License as published by
7 the Free Software Foundation; either version 2.1 of the License, or (at your
8 option) any later version.
9
10 The GNU MP Library is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
12 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
13 License for more details.
14
15 You should have received a copy of the GNU Lesser General Public License
16 along with the GNU MP Library; see the file COPYING.LIB. If not,
17 see <https://www.gnu.org/licenses/>. */
18
19#include "sysdep.h"
20#include "asm-syntax.h"
21
22#define PARMS 4+12 /* space for 3 saved regs */
23#define RES PARMS
24#define S RES+4
25#define SIZE S+4
26#define CNT SIZE+4
27
28 .text
29ENTRY (__mpn_lshift)
30
31 pushl %edi
32 cfi_adjust_cfa_offset (4)
33 pushl %esi
34 cfi_adjust_cfa_offset (4)
35 pushl %ebx
36 cfi_adjust_cfa_offset (4)
37
38 movl RES(%esp),%edi
39 cfi_rel_offset (edi, 8)
40 movl S(%esp),%esi
41 cfi_rel_offset (esi, 4)
42 movl SIZE(%esp),%edx
43 movl CNT(%esp),%ecx
44 subl $4,%esi /* adjust s_ptr */
45
46 movl (%esi,%edx,4),%ebx /* read most significant limb */
47 cfi_rel_offset (ebx, 0)
48 cfi_remember_state
49 xorl %eax,%eax
50 shldl %cl,%ebx,%eax /* compute carry limb */
51 decl %edx
52 jz L(end)
53 pushl %eax /* push carry limb onto stack */
54 cfi_adjust_cfa_offset (4)
55 testb $1,%dl
56 jnz L(1) /* enter loop in the middle */
57 movl %ebx,%eax
58
59 ALIGN (3)
60L(oop): movl (%esi,%edx,4),%ebx /* load next lower limb */
61 shldl %cl,%ebx,%eax /* compute result limb */
62 movl %eax,(%edi,%edx,4) /* store it */
63 decl %edx
64L(1): movl (%esi,%edx,4),%eax
65 shldl %cl,%eax,%ebx
66 movl %ebx,(%edi,%edx,4)
67 decl %edx
68 jnz L(oop)
69
70 shll %cl,%eax /* compute least significant limb */
71 movl %eax,(%edi) /* store it */
72
73 popl %eax /* pop carry limb */
74 cfi_adjust_cfa_offset (-4)
75
76 popl %ebx
77 cfi_adjust_cfa_offset (-4)
78 cfi_restore (ebx)
79 popl %esi
80 cfi_adjust_cfa_offset (-4)
81 cfi_restore (esi)
82 popl %edi
83 cfi_adjust_cfa_offset (-4)
84 cfi_restore (edi)
85
86 ret
87
88 cfi_restore_state
89L(end): shll %cl,%ebx /* compute least significant limb */
90 movl %ebx,(%edi) /* store it */
91
92 popl %ebx
93 cfi_adjust_cfa_offset (-4)
94 cfi_restore (ebx)
95 popl %esi
96 cfi_adjust_cfa_offset (-4)
97 cfi_restore (esi)
98 popl %edi
99 cfi_adjust_cfa_offset (-4)
100 cfi_restore (edi)
101
102 ret
103END (__mpn_lshift)
104

source code of glibc/sysdeps/i386/lshift.S