about summary refs log tree commit diff
path: root/sysdeps/x86_64/multiarch/strncat-evex.S
blob: 1ef3a222094aa9f00f1b3106bd133aee6b858f59 (plain) (blame)
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
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
/* {wcs|str}ncat  with 256/512-bit EVEX.
   Copyright (C) 2022 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
   <https://www.gnu.org/licenses/>.  */

#include <isa-level.h>

#if ISA_SHOULD_BUILD (4)

	/* Use evex-masked stores for small sizes. Turned off at the
	   moment.  */
# define USE_EVEX_MASKED_STORE	0

# include <sysdep.h>

# ifndef VEC_SIZE
#  include "x86-evex256-vecs.h"
# endif

# ifndef STRNCAT
#  define STRNCAT	__strncat_evex
# endif


# ifdef USE_AS_WCSCPY
#  define MOVCHAR	movl
#  define VMOVU_MASK	vmovdqu32
#  define VPMIN	vpminud
#  define VPTESTN	vptestnmd
#  define VPTEST	vptestmd
#  define VPCMPEQ	vpcmpeqd
#  define CHAR_SIZE	4

#  define REP_MOVS	rep movsd

#  define VMASK_REG	VR10
#  define FIND_FIRST_ONE(src, dst)	movl $CHAR_PER_VEC, %dst; bsf %src, %dst

#  define USE_WIDE_CHAR
# else
#  define MOVCHAR	movb
#  define VMOVU_MASK	vmovdqu8
#  define VPMIN	vpminub
#  define VPTESTN	vptestnmb
#  define VPTEST	vptestmb
#  define VPCMPEQ	vpcmpeqb
#  define CHAR_SIZE	1

#  define REP_MOVS	rep movsb

#  define VMASK_REG	VRCX
#  define FIND_FIRST_ONE(src, dst)	tzcnt %src, %dst

# endif

# include "strncpy-or-cat-overflow-def.h"

# include "reg-macros.h"


# define VZERO	VMM(7)
# define VZERO_128	VMM_128(7)

# define PAGE_SIZE	4096
# define CHAR_PER_VEC	(VEC_SIZE / CHAR_SIZE)

	.section SECTION(.text), "ax", @progbits
ENTRY(STRNCAT)
# ifdef __ILP32__
	/* Clear the upper 32 bits.  */
	movl	%edx, %edx
# endif

	movq	%rdi, %rax

	/* NB: It's safe to filter out zero-length strings WITHOUT
	   setting null-term. Destination MUST be a null-terminated
	   string so essentially the work is already done.  */
# ifdef USE_AS_WCSCPY
	leaq	-1(%rdx), %rcx
	shrq	$56, %rcx
	jnz	L(zero_len)
# else
	test	%rdx, %rdx
	jle	L(zero_len)
# endif

# include "strcat-strlen-evex.h.S"

	movl	%esi, %ecx
	andl	$(PAGE_SIZE - 1), %ecx
	cmpl	$(PAGE_SIZE - VEC_SIZE), %ecx
	ja	L(page_cross)
L(page_cross_continue):
	VMOVU	(%rsi), %VMM(0)
	VPTESTN	%VMM(0), %VMM(0), %k0

	/* If USE_EVEX_MASK_STORE is enabled then we just handle length
	   <= CHAR_PER_VEC with masked instructions (which have
	   potential for dramatically bad perf if dst splits a page and
	   is not in the TLB).  */
# if USE_EVEX_MASKED_STORE
	KMOV	%k0, %VRCX
	FIND_FIRST_ONE (VRCX, VR8)
	cmpq	%r8, %rdx
	jbe	L(less_1x_vec)

	test	%VRCX, %VRCX
	jz	L(more_1x_vec)

	blsmsk	%VRCX, %VRCX
	KMOV	%VRCX, %k1
	VMOVU_MASK %VMM(0), (%rdi){%k1}
	ret

L(less_1x_vec):
	mov	$-1, %VRCX
	bzhi	%VRDX, %VRCX, %VRCX
	KMOV	%VRCX, %k1
	MOVCHAR	$0, (%rdi, %rdx, CHAR_SIZE)
	VMOVU_MASK %VMM(0), (%rdi){%k1}

	ret
# else
	KMOV	%k0, %VMASK_REG
	/* tzcnt for strncat and `movl $CHAR_PER_VEC, %VRCX; bsf
	   %VMASK_REG, %VRCX` for wcsncat.  */
	FIND_FIRST_ONE (VMASK_REG, VRCX)
	cmpq	%rcx, %rdx
	jbe	L(less_1x_vec)

	/* If there were no zero-CHARs (rcx was zero before
	   FIND_FIRST_ONE), then ecx will be $CHAR_PER_VEC.  */
	cmpl	$CHAR_PER_VEC, %ecx
	je	L(more_1x_vec)

	movl	%ecx, %edx

L(less_1x_vec):
#  if VEC_SIZE == 64
	cmpl	$(32 / CHAR_SIZE), %edx
	jae	L(copy_32_63)
#  endif

	cmpl	$(16 / CHAR_SIZE), %edx
	jae	L(copy_16_31)


	cmpl	$(8 / CHAR_SIZE), %edx
	jae	L(copy_8_15)

#  ifdef USE_AS_WCSCPY
	vmovd	%VMM_128(0), (%rdi)
	MOVCHAR	$0, (%rdi, %rdx, CHAR_SIZE)
	ret
#  else

	cmpl	$4, %edx
	jae	L(copy_4_7)

	movzbl	(%rsi), %ecx
	cmpl	$1, %edx
	jbe	L(set_null_term)

	movzwl	1(%rsi), %esi
	movw	%si, 1(%rdi)

	.p2align 4,, 1
L(set_null_term):
	movb	%cl, (%rdi)
	MOVCHAR	$0, (%rdi, %rdx)
	ret
#  endif

#  if VEC_SIZE == 64
	.p2align 4,, 6
L(copy_32_63):
	VMOVU	-(32)(%rsi, %rdx, CHAR_SIZE), %VMM_256(1)
	VMOVU	%VMM_256(0), (%rdi)
	VMOVU	%VMM_256(1), -(32)(%rdi, %rdx, CHAR_SIZE)
	MOVCHAR	$0, (%rdi, %rdx, CHAR_SIZE)
	ret
#  endif
	.p2align 4,, 6
L(copy_16_31):
	/* Use xmm1 explicitly here as it won't require a `vzeroupper`
	   and will save code size.  */
	vmovdqu	-(16)(%rsi, %rdx, CHAR_SIZE), %xmm1
	VMOVU	%VMM_128(0), (%rdi)
	vmovdqu	%xmm1, -(16)(%rdi, %rdx, CHAR_SIZE)
	MOVCHAR	$0, (%rdi, %rdx, CHAR_SIZE)
	ret

	.p2align 4,, 2
L(copy_8_15):
	movq	-(8)(%rsi, %rdx, CHAR_SIZE), %rcx
	vmovq	%VMM_128(0), (%rdi)
	movq	%rcx, -(8)(%rdi, %rdx, CHAR_SIZE)
	MOVCHAR	$0, (%rdi, %rdx, CHAR_SIZE)
	ret

#  ifndef USE_AS_WCSCPY
	.p2align 4,, 12
L(copy_4_7):
	movl	-(4)(%rsi, %rdx, CHAR_SIZE), %ecx
	vmovd	%VMM_128(0), (%rdi)
	movl	%ecx, -(4)(%rdi, %rdx, CHAR_SIZE)
	MOVCHAR	$0, (%rdi, %rdx, CHAR_SIZE)
	ret
#  endif

# endif
	.p2align 4,, 4
L(zero_len):
# ifdef USE_AS_WCSCPY
	test	%rdx, %rdx
# endif
	jne	OVERFLOW_STRCAT
	ret

	.p2align 4,, 8
L(more_1x_vec):
	VMOVU	%VMM(0), (%rdi)

	/* We are going to align rsi here so will need to be able to re-
	   adjust rdi/rdx afterwords. NB: We filtered out huge lengths
	   so rsi + rdx * CHAR_SIZE cannot overflow.  */

	leaq	(VEC_SIZE * -1)(%rsi, %rdx, CHAR_SIZE), %rdx
	subq	%rsi, %rdi
	andq	$-(VEC_SIZE), %rsi
L(loop_last_4x_vec):
	addq	%rsi, %rdi
	subq	%rsi, %rdx
# ifdef USE_AS_WCSCPY
	shrq	$2, %rdx
# endif

	/* Will need this regardless.  */
	VMOVA	(VEC_SIZE * 1)(%rsi), %VMM(1)
	VPTESTN	%VMM(1), %VMM(1), %k0
	KMOV	%k0, %VMASK_REG

	cmpq	$(CHAR_PER_VEC * 2), %rdx
	ja	L(more_2x_vec)

L(last_2x_vec):
	FIND_FIRST_ONE (VMASK_REG, VRCX)
	cmpl	%ecx, %edx
	jbe	L(ret_vec_x1_len)

	/* If there were no zero-CHARs (rcx was zero before
	   FIND_FIRST_ONE), then ecx will be $CHAR_PER_VEC.  */
	cmpl	$CHAR_PER_VEC, %ecx
	jne	L(ret_vec_x1)

	VMOVA	(VEC_SIZE * 2)(%rsi), %VMM(2)
	VMOVU	%VMM(1), (VEC_SIZE * 1)(%rdi)
	VPTESTN	%VMM(2), %VMM(2), %k0
	KMOV	%k0, %VRCX
	addl	$-CHAR_PER_VEC, %edx
	bzhi	%VRDX, %VRCX, %VR8
	jz	L(ret_vec_x2_len)
L(ret_vec_x2):
	bsf	%VRCX, %VRDX
L(ret_vec_x2_len):
	VMOVU	(VEC_SIZE * 2 -(VEC_SIZE))(%rsi, %rdx, CHAR_SIZE), %VMM(0)
	MOVCHAR	$0, (VEC_SIZE * 2)(%rdi, %rdx, CHAR_SIZE)
	VMOVU	%VMM(0), (VEC_SIZE * 2 -(VEC_SIZE))(%rdi, %rdx, CHAR_SIZE)
	ret

	.p2align 4,, 4
L(ret_vec_x1_len):
	movl	%edx, %ecx
L(ret_vec_x1):
	VMOVU	(VEC_SIZE -(VEC_SIZE))(%rsi, %rcx, CHAR_SIZE), %VMM(0)
	MOVCHAR	$0, (VEC_SIZE)(%rdi, %rcx, CHAR_SIZE)
	VMOVU	%VMM(0), (VEC_SIZE-(VEC_SIZE))(%rdi, %rcx, CHAR_SIZE)
	VZEROUPPER_RETURN


	.p2align 4,, 8
L(last_4x_vec):
	addl	$-(CHAR_PER_VEC * 4), %edx
	VMOVA	(VEC_SIZE * 5)(%rsi), %VMM(1)
	VPTESTN	%VMM(1), %VMM(1), %k0
	KMOV	%k0, %VMASK_REG
	subq	$-(VEC_SIZE * 4), %rsi
	subq	$-(VEC_SIZE * 4), %rdi
	cmpl	$(CHAR_PER_VEC * 2), %edx
	jbe	L(last_2x_vec)
	.p2align 4,, 8
L(more_2x_vec):
# ifdef USE_AS_WCSCPY
	xorl	%ecx, %ecx
# endif
	bsf	%VMASK_REG, %VRCX
	jnz	L(ret_vec_x1)

	VMOVA	(VEC_SIZE * 2)(%rsi), %VMM(2)
	VMOVU	%VMM(1), (VEC_SIZE * 1)(%rdi)
	VPTESTN	%VMM(2), %VMM(2), %k0
	KMOV	%k0, %VRCX
	test	%VRCX, %VRCX
	jnz	L(ret_vec_x2)

	VMOVA	(VEC_SIZE * 3)(%rsi), %VMM(3)
	VMOVU	%VMM(2), (VEC_SIZE * 2)(%rdi)
	VPTESTN	%VMM(3), %VMM(3), %k0
	KMOV	%k0, %VMASK_REG

	cmpq	$(CHAR_PER_VEC * 4), %rdx
	ja	L(more_4x_vec)

	/* Adjust length before going to L(ret_vec_x3_len) or
	   L(ret_vec_x3).  */
	addl	$(CHAR_PER_VEC * -2), %edx

	FIND_FIRST_ONE (VMASK_REG, VRCX)
	cmpl	%ecx, %edx
	jbe	L(ret_vec_x3_len)

	/* If there were no zero-CHARs (rcx was zero before
	   FIND_FIRST_ONE), then ecx will be $CHAR_PER_VEC.  */
	cmpl	$CHAR_PER_VEC, %ecx
	jne	L(ret_vec_x3)

	VMOVA	(VEC_SIZE * 4)(%rsi), %VMM(4)
	VMOVU	%VMM(3), (VEC_SIZE * 3)(%rdi)
	VPTESTN	%VMM(4), %VMM(4), %k0
	KMOV	%k0, %VRCX
	addl	$-CHAR_PER_VEC, %edx
	bzhi	%VRDX, %VRCX, %VR8
	jz	L(ret_vec_x4_len)
L(ret_vec_x4):
	bsf	%VRCX, %VRDX
L(ret_vec_x4_len):
	VMOVU	(VEC_SIZE * 4 -(VEC_SIZE))(%rsi, %rdx, CHAR_SIZE), %VMM(0)
	MOVCHAR	$0, (VEC_SIZE * 4)(%rdi, %rdx, CHAR_SIZE)
	VMOVU	%VMM(0), (VEC_SIZE * 4 -(VEC_SIZE))(%rdi, %rdx, CHAR_SIZE)
	ret

	.p2align 4,, 4
L(ret_vec_x3_len):
	movl	%edx, %ecx
L(ret_vec_x3):
	VMOVU	(VEC_SIZE * 3 -(VEC_SIZE))(%rsi, %rcx, CHAR_SIZE), %VMM(0)
	MOVCHAR	$0, (VEC_SIZE * 3)(%rdi, %rcx, CHAR_SIZE)
	VMOVU	%VMM(0), (VEC_SIZE * 3-(VEC_SIZE))(%rdi, %rcx, CHAR_SIZE)
	ret

	.p2align 4,, 8
L(more_4x_vec):
# ifdef USE_AS_WCSCPY
	xorl	%ecx, %ecx
# endif
	bsf	%VMASK_REG, %VRCX
	jnz	L(ret_vec_x3)

	VMOVA	(VEC_SIZE * 4)(%rsi), %VMM(4)
	VMOVU	%VMM(3), (VEC_SIZE * 3)(%rdi)
	VPTESTN	%VMM(4), %VMM(4), %k0
	KMOV	%k0, %VRCX
	test	%VRCX, %VRCX
	jnz	L(ret_vec_x4)

	VMOVU	%VMM(4), (VEC_SIZE * 4)(%rdi)

	/* Check if we are near the end before aligning.  */
	cmpq	$(CHAR_PER_VEC * 8), %rdx
	jbe	L(last_4x_vec)


	/* Add rsi to rdx (length) before aligning rsi. NB: Since we
	   filtered out huge lengths this cannot overflow.  */
# ifdef USE_AS_WCSCPY
	leaq	(%rsi, %rdx, CHAR_SIZE), %rdx
# else
	addq	%rsi, %rdx
# endif

	/* Subtract rsi from rdi before aligning (add back will have
	   correct rdi for aligned rsi).  */
	subq	%rsi, %rdi
	subq	$-(VEC_SIZE * 5), %rsi
	andq	$(VEC_SIZE * -4), %rsi

	/* Load first half of the loop before entry.  */
	VMOVA	(VEC_SIZE * 0 + 0)(%rsi), %VMM(0)
	VMOVA	(VEC_SIZE * 1 + 0)(%rsi), %VMM(1)
	VMOVA	(VEC_SIZE * 2 + 0)(%rsi), %VMM(2)
	VMOVA	(VEC_SIZE * 3 + 0)(%rsi), %VMM(3)

	VPMIN	%VMM(0), %VMM(1), %VMM(4)
	VPMIN	%VMM(2), %VMM(3), %VMM(6)
	VPTESTN	%VMM(4), %VMM(4), %k2
	VPTESTN	%VMM(6), %VMM(6), %k4

	/* Offset rsi by VEC_SIZE so that we can jump to
	   L(loop_last_4x_vec).  */
	addq	$-(VEC_SIZE), %rsi
	KORTEST	%k2, %k4
	jnz	L(loop_4x_done)

	/* Store loop end in r9.  */
	leaq	-(VEC_SIZE * 5)(%rdx), %r9

	.p2align 4,, 11
L(loop_4x_vec):
	VMOVU	%VMM(0), (VEC_SIZE * 1 + 0)(%rdi, %rsi)
	VMOVU	%VMM(1), (VEC_SIZE * 2 + 0)(%rdi, %rsi)
	VMOVU	%VMM(2), (VEC_SIZE * 3 + 0)(%rdi, %rsi)
	VMOVU	%VMM(3), (VEC_SIZE * 4 + 0)(%rdi, %rsi)

	subq	$(VEC_SIZE * -4), %rsi
	cmpq	%rsi, %r9
	jbe	L(loop_last_4x_vec)

	VMOVA	(VEC_SIZE * 1 + 0)(%rsi), %VMM(0)
	VMOVA	(VEC_SIZE * 2 + 0)(%rsi), %VMM(1)
	VMOVA	(VEC_SIZE * 3 + 0)(%rsi), %VMM(2)
	VMOVA	(VEC_SIZE * 4 + 0)(%rsi), %VMM(3)

	VPMIN	%VMM(0), %VMM(1), %VMM(4)
	VPMIN	%VMM(2), %VMM(3), %VMM(6)
	VPTESTN	%VMM(4), %VMM(4), %k2
	VPTESTN	%VMM(6), %VMM(6), %k4
	KORTEST	%k2, %k4
	jz	L(loop_4x_vec)

L(loop_4x_done):
	VPTESTN	%VMM(0), %VMM(0), %k0
	KMOV	%k0, %VRCX
	/* Restore rdi (dst).  */
	addq	%rsi, %rdi

	/* L(ret_vec_x1) expects rcx to have position of zero-CHAR so
	   test with bsf.  */
	bsf	%VRCX, %VRCX
	jnz	L(ret_vec_x1)
	VMOVU	%VMM(0), (VEC_SIZE * 1 + 0)(%rdi)

	KMOV	%k2, %VRCX
	test	%VRCX, %VRCX
	jnz	L(ret_vec_x2)
	VMOVU	%VMM(1), (VEC_SIZE * 2 + 0)(%rdi)

	VPTESTN	%VMM(2), %VMM(2), %k0
	KMOV	%k0, %VRCX
	bsf	%VRCX, %VRCX
	jnz	L(ret_vec_x3)
	VMOVU	%VMM(2), (VEC_SIZE * 3 + 0)(%rdi)

	KMOV	%k4, %VRCX
	bsf	%VRCX, %VRCX
	VMOVU	((VEC_SIZE * 4)-(VEC_SIZE - CHAR_SIZE))(%rsi, %rcx, CHAR_SIZE), %VMM(0)
	VMOVU	%VMM(0), ((VEC_SIZE * 4 + 0)-(VEC_SIZE - CHAR_SIZE))(%rdi, %rcx, CHAR_SIZE)
	ret


	.p2align 4,, 4
L(page_cross):
	movq	%rsi, %r8
	andq	$(VEC_SIZE * -1), %r8
	VPCMPEQ	(%r8), %VZERO, %k0

# ifdef USE_AS_WCSCPY
	KMOV	%k0, %VR9
	shrl	$2, %ecx
	andl	$(CHAR_PER_VEC - 1), %ecx
	shrx	%VRCX, %VR9, %VRCX
# else
	KMOV	%k0, %VRCX
	shrx	%VRSI, %VRCX, %VRCX
# endif

	subl	%esi, %r8d
	andl	$(VEC_SIZE - 1), %r8d
# ifdef USE_AS_WCSCPY
	shrl	$2, %r8d
# endif
	cmpq	%r8, %rdx
	jbe	L(page_cross_small)
	/* Optimizing more for space as this is very cold code. This
	   saves 2x cache lines.  */

	/* This adds once to the later result which will get correct
	   copy bounds. NB: this can never zero-out a non-zero RCX as
	   to be in the page cross case rsi cannot be aligned and we
	   already right-shift rcx by the misalignment.  */
	shl	%VRCX
	jz	L(page_cross_continue)
	bsf	%VRCX, %VRCX
	REP_MOVS
	ret

L(page_cross_small):
	tzcnt	%VRCX, %VRCX
	jz	L(page_cross_setz)
	cmpl	%edx, %ecx
	cmova	%edx, %ecx

# ifdef USE_AS_WCSCPY
	rep	movsd
# else
	rep	movsb
# endif
L(page_cross_setz):
	MOVCHAR	$0, (%rdi)
	ret
END(STRNCAT)
#endif