1/* fast SSE2 memrchr with 64 byte loop and pmaxub instruction using
2
3   Copyright (C) 2011-2021 Free Software Foundation, Inc.
4   This file is part of the GNU C Library.
5
6   The GNU C Library is free software; you can redistribute it and/or
7   modify it under the terms of the GNU Lesser General Public
8   License as published by the Free Software Foundation; either
9   version 2.1 of the License, or (at your option) any later version.
10
11   The GNU C Library is distributed in the hope that it will be useful,
12   but WITHOUT ANY WARRANTY; without even the implied warranty of
13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14   Lesser General Public License for more details.
15
16   You should have received a copy of the GNU Lesser General Public
17   License along with the GNU C Library; if not, see
18   <https://www.gnu.org/licenses/>.  */
19
20#include <sysdep.h>
21
22	.text
23ENTRY (__memrchr)
24	movd	%esi, %xmm1
25
26	sub	$16, %RDX_LP
27	jbe	L(length_less16)
28
29	punpcklbw	%xmm1, %xmm1
30	punpcklbw	%xmm1, %xmm1
31
32	add	%RDX_LP, %RDI_LP
33	pshufd	$0, %xmm1, %xmm1
34
35	movdqu	(%rdi), %xmm0
36	pcmpeqb	%xmm1, %xmm0
37
38/* Check if there is a match.  */
39	pmovmskb	%xmm0, %eax
40	test	%eax, %eax
41	jnz	L(matches0)
42
43	sub	$64, %rdi
44	mov	%edi, %ecx
45	and	$15, %ecx
46	jz	L(loop_prolog)
47
48	add	$16, %rdi
49	add	$16, %rdx
50	and	$-16, %rdi
51	sub	%rcx, %rdx
52
53	.p2align 4
54L(loop_prolog):
55	sub	$64, %rdx
56	jbe	L(exit_loop)
57
58	movdqa	48(%rdi), %xmm0
59	pcmpeqb	%xmm1, %xmm0
60	pmovmskb	%xmm0, %eax
61	test	%eax, %eax
62	jnz	L(matches48)
63
64	movdqa	32(%rdi), %xmm2
65	pcmpeqb	%xmm1, %xmm2
66	pmovmskb	%xmm2, %eax
67	test	%eax, %eax
68	jnz	L(matches32)
69
70	movdqa	16(%rdi), %xmm3
71	pcmpeqb	%xmm1, %xmm3
72	pmovmskb	%xmm3, %eax
73	test	%eax, %eax
74	jnz	L(matches16)
75
76	movdqa	(%rdi), %xmm4
77	pcmpeqb	%xmm1, %xmm4
78	pmovmskb	%xmm4, %eax
79	test	%eax, %eax
80	jnz	L(matches0)
81
82	sub	$64, %rdi
83	sub	$64, %rdx
84	jbe	L(exit_loop)
85
86	movdqa	48(%rdi), %xmm0
87	pcmpeqb	%xmm1, %xmm0
88	pmovmskb	%xmm0, %eax
89	test	%eax, %eax
90	jnz	L(matches48)
91
92	movdqa	32(%rdi), %xmm2
93	pcmpeqb	%xmm1, %xmm2
94	pmovmskb	%xmm2, %eax
95	test	%eax, %eax
96	jnz	L(matches32)
97
98	movdqa	16(%rdi), %xmm3
99	pcmpeqb	%xmm1, %xmm3
100	pmovmskb	%xmm3, %eax
101	test	%eax, %eax
102	jnz	L(matches16)
103
104	movdqa	(%rdi), %xmm3
105	pcmpeqb	%xmm1, %xmm3
106	pmovmskb	%xmm3, %eax
107	test	%eax, %eax
108	jnz	L(matches0)
109
110	mov	%edi, %ecx
111	and	$63, %ecx
112	jz	L(align64_loop)
113
114	add	$64, %rdi
115	add	$64, %rdx
116	and	$-64, %rdi
117	sub	%rcx, %rdx
118
119	.p2align 4
120L(align64_loop):
121	sub	$64, %rdi
122	sub	$64, %rdx
123	jbe	L(exit_loop)
124
125	movdqa	(%rdi), %xmm0
126	movdqa	16(%rdi), %xmm2
127	movdqa	32(%rdi), %xmm3
128	movdqa	48(%rdi), %xmm4
129
130	pcmpeqb	%xmm1, %xmm0
131	pcmpeqb	%xmm1, %xmm2
132	pcmpeqb	%xmm1, %xmm3
133	pcmpeqb	%xmm1, %xmm4
134
135	pmaxub	%xmm3, %xmm0
136	pmaxub	%xmm4, %xmm2
137	pmaxub	%xmm0, %xmm2
138	pmovmskb	%xmm2, %eax
139
140	test	%eax, %eax
141	jz	L(align64_loop)
142
143	pmovmskb	%xmm4, %eax
144	test	%eax, %eax
145	jnz	L(matches48)
146
147	pmovmskb	%xmm3, %eax
148	test	%eax, %eax
149	jnz	L(matches32)
150
151	movdqa	16(%rdi), %xmm2
152
153	pcmpeqb	%xmm1, %xmm2
154	pcmpeqb	(%rdi), %xmm1
155
156	pmovmskb	%xmm2, %eax
157	test	%eax, %eax
158	jnz	L(matches16)
159
160	pmovmskb	%xmm1, %eax
161	bsr	%eax, %eax
162
163	add	%rdi, %rax
164	ret
165
166	.p2align 4
167L(exit_loop):
168	add	$64, %edx
169	cmp	$32, %edx
170	jbe	L(exit_loop_32)
171
172	movdqa	48(%rdi), %xmm0
173	pcmpeqb	%xmm1, %xmm0
174	pmovmskb	%xmm0, %eax
175	test	%eax, %eax
176	jnz	L(matches48)
177
178	movdqa	32(%rdi), %xmm2
179	pcmpeqb	%xmm1, %xmm2
180	pmovmskb	%xmm2, %eax
181	test	%eax, %eax
182	jnz	L(matches32)
183
184	movdqa	16(%rdi), %xmm3
185	pcmpeqb	%xmm1, %xmm3
186	pmovmskb	%xmm3, %eax
187	test	%eax, %eax
188	jnz	L(matches16_1)
189	cmp	$48, %edx
190	jbe	L(return_null)
191
192	pcmpeqb	(%rdi), %xmm1
193	pmovmskb	%xmm1, %eax
194	test	%eax, %eax
195	jnz	L(matches0_1)
196	xor	%eax, %eax
197	ret
198
199	.p2align 4
200L(exit_loop_32):
201	movdqa	48(%rdi), %xmm0
202	pcmpeqb	%xmm1, %xmm0
203	pmovmskb	%xmm0, %eax
204	test	%eax, %eax
205	jnz	L(matches48_1)
206	cmp	$16, %edx
207	jbe	L(return_null)
208
209	pcmpeqb	32(%rdi), %xmm1
210	pmovmskb	%xmm1, %eax
211	test	%eax, %eax
212	jnz	L(matches32_1)
213	xor	%eax, %eax
214	ret
215
216	.p2align 4
217L(matches0):
218	bsr	%eax, %eax
219	add	%rdi, %rax
220	ret
221
222	.p2align 4
223L(matches16):
224	bsr	%eax, %eax
225	lea	16(%rax, %rdi), %rax
226	ret
227
228	.p2align 4
229L(matches32):
230	bsr	%eax, %eax
231	lea	32(%rax, %rdi), %rax
232	ret
233
234	.p2align 4
235L(matches48):
236	bsr	%eax, %eax
237	lea	48(%rax, %rdi), %rax
238	ret
239
240	.p2align 4
241L(matches0_1):
242	bsr	%eax, %eax
243	sub	$64, %rdx
244	add	%rax, %rdx
245	jl	L(return_null)
246	add	%rdi, %rax
247	ret
248
249	.p2align 4
250L(matches16_1):
251	bsr	%eax, %eax
252	sub	$48, %rdx
253	add	%rax, %rdx
254	jl	L(return_null)
255	lea	16(%rdi, %rax), %rax
256	ret
257
258	.p2align 4
259L(matches32_1):
260	bsr	%eax, %eax
261	sub	$32, %rdx
262	add	%rax, %rdx
263	jl	L(return_null)
264	lea	32(%rdi, %rax), %rax
265	ret
266
267	.p2align 4
268L(matches48_1):
269	bsr	%eax, %eax
270	sub	$16, %rdx
271	add	%rax, %rdx
272	jl	L(return_null)
273	lea	48(%rdi, %rax), %rax
274	ret
275
276	.p2align 4
277L(return_null):
278	xor	%eax, %eax
279	ret
280
281	.p2align 4
282L(length_less16_offset0):
283	test	%edx, %edx
284	jz	L(return_null)
285
286	mov	%dl, %cl
287	pcmpeqb	(%rdi), %xmm1
288
289	mov	$1, %edx
290	sal	%cl, %edx
291	sub	$1, %edx
292
293	pmovmskb	%xmm1, %eax
294
295	and	%edx, %eax
296	test	%eax, %eax
297	jz	L(return_null)
298
299	bsr	%eax, %eax
300	add	%rdi, %rax
301	ret
302
303	.p2align 4
304L(length_less16):
305	punpcklbw	%xmm1, %xmm1
306	punpcklbw	%xmm1, %xmm1
307
308	add	$16, %edx
309
310	pshufd	$0, %xmm1, %xmm1
311
312	mov	%edi, %ecx
313	and	$15, %ecx
314	jz	L(length_less16_offset0)
315
316	mov	%cl, %dh
317	mov	%ecx, %esi
318	add	%dl, %dh
319	and	$-16, %rdi
320
321	sub	$16, %dh
322	ja	L(length_less16_part2)
323
324	pcmpeqb	(%rdi), %xmm1
325	pmovmskb	%xmm1, %eax
326
327	sar	%cl, %eax
328	mov	%dl, %cl
329
330	mov	$1, %edx
331	sal	%cl, %edx
332	sub	$1, %edx
333
334	and	%edx, %eax
335	test	%eax, %eax
336	jz	L(return_null)
337
338	bsr	%eax, %eax
339	add	%rdi, %rax
340	add	%rsi, %rax
341	ret
342
343	.p2align 4
344L(length_less16_part2):
345	movdqa	16(%rdi), %xmm2
346	pcmpeqb	%xmm1, %xmm2
347	pmovmskb	%xmm2, %eax
348
349	mov	%dh, %cl
350	mov	$1, %edx
351	sal	%cl, %edx
352	sub	$1, %edx
353
354	and	%edx, %eax
355
356	test	%eax, %eax
357	jnz	L(length_less16_part2_return)
358
359	pcmpeqb	(%rdi), %xmm1
360	pmovmskb	%xmm1, %eax
361
362	mov	%esi, %ecx
363	sar	%cl, %eax
364	test	%eax, %eax
365	jz	L(return_null)
366
367	bsr	%eax, %eax
368	add	%rdi, %rax
369	add	%rsi, %rax
370	ret
371
372	.p2align 4
373L(length_less16_part2_return):
374	bsr	%eax, %eax
375	lea	16(%rax, %rdi), %rax
376	ret
377
378END (__memrchr)
379weak_alias (__memrchr, memrchr)
380