File: memset-vec-unaligned-erms.S

package info (click to toggle)
glibc 2.28-10
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, buster, buster-proposed-updates, experimental, sid
  • size: 272,168 kB
  • sloc: ansic: 1,008,602; asm: 259,607; makefile: 11,271; sh: 10,477; python: 6,910; cpp: 4,992; perl: 2,258; awk: 2,005; yacc: 290; pascal: 182; sed: 73
file content (282 lines) | stat: -rw-r--r-- 7,203 bytes parent folder | download | duplicates (3)
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
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
/* memset/bzero with unaligned store and rep stosb
   Copyright (C) 2016-2018 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, see
   <http://www.gnu.org/licenses/>.  */

/* memset is implemented as:
   1. Use overlapping store to avoid branch.
   2. If size is less than VEC, use integer register stores.
   3. If size is from VEC_SIZE to 2 * VEC_SIZE, use 2 VEC stores.
   4. If size is from 2 * VEC_SIZE to 4 * VEC_SIZE, use 4 VEC stores.
   5. If size is more to 4 * VEC_SIZE, align to 4 * VEC_SIZE with
      4 VEC stores and store 4 * VEC at a time until done.  */

#include <sysdep.h>

#ifndef MEMSET_CHK_SYMBOL
# define MEMSET_CHK_SYMBOL(p,s)		MEMSET_SYMBOL(p, s)
#endif

#ifndef WMEMSET_CHK_SYMBOL
# define WMEMSET_CHK_SYMBOL(p,s)	WMEMSET_SYMBOL(p, s)
#endif

#ifndef VZEROUPPER
# if VEC_SIZE > 16
#  define VZEROUPPER			vzeroupper
# else
#  define VZEROUPPER
# endif
#endif

#ifndef VZEROUPPER_SHORT_RETURN
# if VEC_SIZE > 16
#  define VZEROUPPER_SHORT_RETURN	vzeroupper
# else
#  define VZEROUPPER_SHORT_RETURN	rep
# endif
#endif

#ifndef MOVQ
# if VEC_SIZE > 16
#  define MOVQ				vmovq
# else
#  define MOVQ				movq
# endif
#endif

/* Threshold to use Enhanced REP STOSB.  Since there is overhead to set
   up REP STOSB operation, REP STOSB isn't faster on short data.  The
   memset micro benchmark in glibc shows that 2KB is the approximate
   value above which REP STOSB becomes faster on processors with
   Enhanced REP STOSB.  Since the stored value is fixed, larger register
   size has minimal impact on threshold.  */
#ifndef REP_STOSB_THRESHOLD
# define REP_STOSB_THRESHOLD		2048
#endif

#ifndef SECTION
# error SECTION is not defined!
#endif

	.section SECTION(.text),"ax",@progbits
#if VEC_SIZE == 16 && IS_IN (libc)
ENTRY (__bzero)
	mov	%RDI_LP, %RAX_LP /* Set return value.  */
	mov	%RSI_LP, %RDX_LP /* Set n.  */
	pxor	%xmm0, %xmm0
	jmp	L(entry_from_bzero)
END (__bzero)
weak_alias (__bzero, bzero)
#endif

#if IS_IN (libc)
# if defined SHARED
ENTRY_CHK (WMEMSET_CHK_SYMBOL (__wmemset_chk, unaligned))
	cmp	%RDX_LP, %RCX_LP
	jb	HIDDEN_JUMPTARGET (__chk_fail)
END_CHK (WMEMSET_CHK_SYMBOL (__wmemset_chk, unaligned))
# endif

ENTRY (WMEMSET_SYMBOL (__wmemset, unaligned))
	shl	$2, %RDX_LP
	WMEMSET_VDUP_TO_VEC0_AND_SET_RETURN (%esi, %rdi)
	jmp	L(entry_from_bzero)
END (WMEMSET_SYMBOL (__wmemset, unaligned))
#endif

#if defined SHARED && IS_IN (libc)
ENTRY_CHK (MEMSET_CHK_SYMBOL (__memset_chk, unaligned))
	cmp	%RDX_LP, %RCX_LP
	jb	HIDDEN_JUMPTARGET (__chk_fail)
END_CHK (MEMSET_CHK_SYMBOL (__memset_chk, unaligned))
#endif

ENTRY (MEMSET_SYMBOL (__memset, unaligned))
	MEMSET_VDUP_TO_VEC0_AND_SET_RETURN (%esi, %rdi)
# ifdef __ILP32__
	/* Clear the upper 32 bits.  */
	mov	%edx, %edx
# endif
L(entry_from_bzero):
	cmpq	$VEC_SIZE, %rdx
	jb	L(less_vec)
	cmpq	$(VEC_SIZE * 2), %rdx
	ja	L(more_2x_vec)
	/* From VEC and to 2 * VEC.  No branch when size == VEC_SIZE.  */
	VMOVU	%VEC(0), -VEC_SIZE(%rdi,%rdx)
	VMOVU	%VEC(0), (%rdi)
	VZEROUPPER
	ret
#if defined USE_MULTIARCH && IS_IN (libc)
END (MEMSET_SYMBOL (__memset, unaligned))

# if VEC_SIZE == 16
ENTRY (__memset_chk_erms)
	cmp	%RDX_LP, %RCX_LP
	jb	HIDDEN_JUMPTARGET (__chk_fail)
END (__memset_chk_erms)

/* Only used to measure performance of REP STOSB.  */
ENTRY (__memset_erms)
	/* Skip zero length.  */
	test	%RDX_LP, %RDX_LP
	jnz	 L(stosb)
	movq	%rdi, %rax
	ret
# else
/* Provide a hidden symbol to debugger.  */
	.hidden	MEMSET_SYMBOL (__memset, erms)
ENTRY (MEMSET_SYMBOL (__memset, erms))
# endif
L(stosb):
	/* Issue vzeroupper before rep stosb.  */
	VZEROUPPER
	mov	%RDX_LP, %RCX_LP
	movzbl	%sil, %eax
	mov	%RDI_LP, %RDX_LP
	rep stosb
	mov	%RDX_LP, %RAX_LP
	ret
# if VEC_SIZE == 16
END (__memset_erms)
# else
END (MEMSET_SYMBOL (__memset, erms))
# endif

# if defined SHARED && IS_IN (libc)
ENTRY_CHK (MEMSET_CHK_SYMBOL (__memset_chk, unaligned_erms))
	cmp	%RDX_LP, %RCX_LP
	jb	HIDDEN_JUMPTARGET (__chk_fail)
END_CHK (MEMSET_CHK_SYMBOL (__memset_chk, unaligned_erms))
# endif

ENTRY (MEMSET_SYMBOL (__memset, unaligned_erms))
	MEMSET_VDUP_TO_VEC0_AND_SET_RETURN (%esi, %rdi)
# ifdef __ILP32__
	/* Clear the upper 32 bits.  */
	mov	%edx, %edx
# endif
	cmp	$VEC_SIZE, %RDX_LP
	jb	L(less_vec)
	cmp	$(VEC_SIZE * 2), %RDX_LP
	ja	L(stosb_more_2x_vec)
	/* From VEC and to 2 * VEC.  No branch when size == VEC_SIZE.  */
	VMOVU	%VEC(0), -VEC_SIZE(%rdi,%rdx)
	VMOVU	%VEC(0), (%rdi)
	VZEROUPPER
	ret

L(stosb_more_2x_vec):
	cmpq	$REP_STOSB_THRESHOLD, %rdx
	ja	L(stosb)
#endif
L(more_2x_vec):
	cmpq  $(VEC_SIZE * 4), %rdx
	ja	L(loop_start)
	VMOVU	%VEC(0), (%rdi)
	VMOVU	%VEC(0), VEC_SIZE(%rdi)
	VMOVU	%VEC(0), -VEC_SIZE(%rdi,%rdx)
	VMOVU	%VEC(0), -(VEC_SIZE * 2)(%rdi,%rdx)
L(return):
	VZEROUPPER
	ret

L(loop_start):
	leaq	(VEC_SIZE * 4)(%rdi), %rcx
	VMOVU	%VEC(0), (%rdi)
	andq	$-(VEC_SIZE * 4), %rcx
	VMOVU	%VEC(0), -VEC_SIZE(%rdi,%rdx)
	VMOVU	%VEC(0), VEC_SIZE(%rdi)
	VMOVU	%VEC(0), -(VEC_SIZE * 2)(%rdi,%rdx)
	VMOVU	%VEC(0), (VEC_SIZE * 2)(%rdi)
	VMOVU	%VEC(0), -(VEC_SIZE * 3)(%rdi,%rdx)
	VMOVU	%VEC(0), (VEC_SIZE * 3)(%rdi)
	VMOVU	%VEC(0), -(VEC_SIZE * 4)(%rdi,%rdx)
	addq	%rdi, %rdx
	andq	$-(VEC_SIZE * 4), %rdx
	cmpq	%rdx, %rcx
	je	L(return)
L(loop):
	VMOVA	%VEC(0), (%rcx)
	VMOVA	%VEC(0), VEC_SIZE(%rcx)
	VMOVA	%VEC(0), (VEC_SIZE * 2)(%rcx)
	VMOVA	%VEC(0), (VEC_SIZE * 3)(%rcx)
	addq	$(VEC_SIZE * 4), %rcx
	cmpq	%rcx, %rdx
	jne	L(loop)
	VZEROUPPER_SHORT_RETURN
	ret
L(less_vec):
	/* Less than 1 VEC.  */
# if VEC_SIZE != 16 && VEC_SIZE != 32 && VEC_SIZE != 64
#  error Unsupported VEC_SIZE!
# endif
# if VEC_SIZE > 32
	cmpb	$32, %dl
	jae	L(between_32_63)
# endif
# if VEC_SIZE > 16
	cmpb	$16, %dl
	jae	L(between_16_31)
# endif
	MOVQ	%xmm0, %rcx
	cmpb	$8, %dl
	jae	L(between_8_15)
	cmpb	$4, %dl
	jae	L(between_4_7)
	cmpb	$1, %dl
	ja	L(between_2_3)
	jb	1f
	movb	%cl, (%rdi)
1:
	VZEROUPPER
	ret
# if VEC_SIZE > 32
	/* From 32 to 63.  No branch when size == 32.  */
L(between_32_63):
	vmovdqu	%ymm0, -32(%rdi,%rdx)
	vmovdqu	%ymm0, (%rdi)
	VZEROUPPER
	ret
# endif
# if VEC_SIZE > 16
	/* From 16 to 31.  No branch when size == 16.  */
L(between_16_31):
	vmovdqu	%xmm0, -16(%rdi,%rdx)
	vmovdqu	%xmm0, (%rdi)
	VZEROUPPER
	ret
# endif
	/* From 8 to 15.  No branch when size == 8.  */
L(between_8_15):
	movq	%rcx, -8(%rdi,%rdx)
	movq	%rcx, (%rdi)
	VZEROUPPER
	ret
L(between_4_7):
	/* From 4 to 7.  No branch when size == 4.  */
	movl	%ecx, -4(%rdi,%rdx)
	movl	%ecx, (%rdi)
	VZEROUPPER
	ret
L(between_2_3):
	/* From 2 to 3.  No branch when size == 2.  */
	movw	%cx, -2(%rdi,%rdx)
	movw	%cx, (%rdi)
	VZEROUPPER
	ret
END (MEMSET_SYMBOL (__memset, unaligned_erms))