summaryrefslogtreecommitdiff
path: root/sysdeps/i386/i586/lshift.S
blob: 59d587934eaaccec4599024cd46c1e6f9326b120 (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
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
/* Pentium optimized __mpn_lshift --
   Copyright (C) 1992, 94, 95, 96, 97, 98, 2000 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C 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 C 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 C Library; 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+16		/* space for 4 saved regs */
#define RES	PARMS
#define S	RES+PTR_SIZE
#define SIZE	S+PTR_SIZE
#define CNT	SIZE+4

	.text
ENTRY (BP_SYM (__mpn_lshift))
	ENTER

	pushl	%edi
	pushl	%esi
	pushl	%ebp
	pushl	%ebx

	movl	RES(%esp),%edi
	movl	S(%esp),%esi
	movl	SIZE(%esp),%ebx
	movl	CNT(%esp),%ecx
#if __BOUNDED_POINTERS__
	shll	$2, %ebx		/* convert limbs to bytes */
	CHECK_BOUNDS_BOTH_WIDE (%edi, RES(%esp), %ebx)
	CHECK_BOUNDS_BOTH_WIDE (%esi, S(%esp), %ebx)
	shrl	$2, %ebx
#endif

/* We can use faster code for shift-by-1 under certain conditions.  */
	cmp	$1,%ecx
	jne	L(normal)
	leal	4(%esi),%eax
	cmpl	%edi,%eax
	jnc	L(special)		/* jump if s_ptr + 1 >= res_ptr */
	leal	(%esi,%ebx,4),%eax
	cmpl	%eax,%edi
	jnc	L(special)		/* jump if res_ptr >= s_ptr + size */

L(normal):
	leal	-4(%edi,%ebx,4),%edi
	leal	-4(%esi,%ebx,4),%esi

	movl	(%esi),%edx
	subl	$4,%esi
	xorl	%eax,%eax
	shldl	%cl,%edx,%eax		/* compute carry limb */
	pushl	%eax			/* push carry limb onto stack */

	decl	%ebx
	pushl	%ebx
	shrl	$3,%ebx
	jz	L(end)

	movl	(%edi),%eax		/* fetch destination cache line */

	ALIGN	(2)
L(oop):	movl	-28(%edi),%eax		/* fetch destination cache line */
	movl	%edx,%ebp

	movl	(%esi),%eax
	movl	-4(%esi),%edx
	shldl	%cl,%eax,%ebp
	shldl	%cl,%edx,%eax
	movl	%ebp,(%edi)
	movl	%eax,-4(%edi)

	movl	-8(%esi),%ebp
	movl	-12(%esi),%eax
	shldl	%cl,%ebp,%edx
	shldl	%cl,%eax,%ebp
	movl	%edx,-8(%edi)
	movl	%ebp,-12(%edi)

	movl	-16(%esi),%edx
	movl	-20(%esi),%ebp
	shldl	%cl,%edx,%eax
	shldl	%cl,%ebp,%edx
	movl	%eax,-16(%edi)
	movl	%edx,-20(%edi)

	movl	-24(%esi),%eax
	movl	-28(%esi),%edx
	shldl	%cl,%eax,%ebp
	shldl	%cl,%edx,%eax
	movl	%ebp,-24(%edi)
	movl	%eax,-28(%edi)

	subl	$32,%esi
	subl	$32,%edi
	decl	%ebx
	jnz	L(oop)

L(end):	popl	%ebx
	andl	$7,%ebx
	jz	L(end2)
L(oop2):
	movl	(%esi),%eax
	shldl	%cl,%eax,%edx
	movl	%edx,(%edi)
	movl	%eax,%edx
	subl	$4,%esi
	subl	$4,%edi
	decl	%ebx
	jnz	L(oop2)

L(end2):
	shll	%cl,%edx		/* compute least significant limb */
	movl	%edx,(%edi)		/* store it */

	popl	%eax			/* pop carry limb */

	popl	%ebx
	popl	%ebp
	popl	%esi
	popl	%edi

	LEAVE
	ret

/* We loop from least significant end of the arrays, which is only
   permissible if the source and destination don't overlap, since the
   function is documented to work for overlapping source and destination.
*/

L(special):
	movl	(%esi),%edx
	addl	$4,%esi

	decl	%ebx
	pushl	%ebx
	shrl	$3,%ebx

	addl	%edx,%edx
	incl	%ebx
	decl	%ebx
	jz	L(Lend)

	movl	(%edi),%eax		/* fetch destination cache line */

	ALIGN	(2)
L(Loop):
	movl	28(%edi),%eax		/* fetch destination cache line */
	movl	%edx,%ebp

	movl	(%esi),%eax
	movl	4(%esi),%edx
	adcl	%eax,%eax
	movl	%ebp,(%edi)
	adcl	%edx,%edx
	movl	%eax,4(%edi)

	movl	8(%esi),%ebp
	movl	12(%esi),%eax
	adcl	%ebp,%ebp
	movl	%edx,8(%edi)
	adcl	%eax,%eax
	movl	%ebp,12(%edi)

	movl	16(%esi),%edx
	movl	20(%esi),%ebp
	adcl	%edx,%edx
	movl	%eax,16(%edi)
	adcl	%ebp,%ebp
	movl	%edx,20(%edi)

	movl	24(%esi),%eax
	movl	28(%esi),%edx
	adcl	%eax,%eax
	movl	%ebp,24(%edi)
	adcl	%edx,%edx
	movl	%eax,28(%edi)

	leal	32(%esi),%esi		/* use leal not to clobber carry */
	leal	32(%edi),%edi
	decl	%ebx
	jnz	L(Loop)

L(Lend):
	popl	%ebx
	sbbl	%eax,%eax		/* save carry in %eax */
	andl	$7,%ebx
	jz	L(Lend2)
	addl	%eax,%eax		/* restore carry from eax */
L(Loop2):
	movl	%edx,%ebp
	movl	(%esi),%edx
	adcl	%edx,%edx
	movl	%ebp,(%edi)

	leal	4(%esi),%esi		/* use leal not to clobber carry */
	leal	4(%edi),%edi
	decl	%ebx
	jnz	L(Loop2)

	jmp	L(L1)
L(Lend2):
	addl	%eax,%eax		/* restore carry from eax */
L(L1):	movl	%edx,(%edi)		/* store last limb */

	sbbl	%eax,%eax
	negl	%eax

	popl	%ebx
	popl	%ebp
	popl	%esi
	popl	%edi

	LEAVE
	ret
END (BP_SYM (__mpn_lshift))