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6c6ab1fc | 1 | /* Optimized strrchr implementation for PowerPC64/POWER7 using cmpb insn. |
d614a753 | 2 | Copyright (C) 2017-2020 Free Software Foundation, Inc. |
6c6ab1fc RS |
3 | This file is part of the GNU C Library. |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Lesser General Public | |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
9 | ||
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
16 | License along with the GNU C Library; if not, see | |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
6c6ab1fc RS |
18 | |
19 | #include <sysdep.h> | |
20 | ||
21 | /* char *[r3] strrchr (char *s [r3], int c [r4]) */ | |
066020c5 | 22 | |
6c6ab1fc RS |
23 | #ifdef __LITTLE_ENDIAN__ |
24 | /* Find the match position from v6 and place result in r6. */ | |
25 | # define CALCULATE_MATCH() \ | |
066020c5 | 26 | vbpermq v6, v6, v10; \ |
6c6ab1fc | 27 | vsldoi v6, v6, v6, 6; \ |
066020c5 | 28 | mfvrd r7, v6; \ |
6c6ab1fc RS |
29 | cntlzd r6, r7; \ |
30 | subfic r6, r6, 15; | |
31 | /* | |
32 | * Find the first null position to mask bytes after null. | |
33 | * (reg): vcmpequb result: v2 for 1st qw v3 for 2nd qw. | |
34 | * Result placed at v2. | |
35 | */ | |
36 | # define FIND_NULL_POS(reg) \ | |
37 | vspltisb v11, -1; \ | |
066020c5 | 38 | vadduqm v11, reg, v11; \ |
6c6ab1fc | 39 | vandc v11, v11, reg; \ |
066020c5 | 40 | vpopcntd v2, v11; \ |
6c6ab1fc RS |
41 | vspltb v11, v2, 15; \ |
42 | vcmpequb. v11, v11, v9; \ | |
43 | blt cr6, 1f; \ | |
44 | vsldoi v9, v0, v9, 1; \ | |
45 | vslo v2, v2, v9; \ | |
46 | 1: \ | |
47 | vsumsws v2, v2, v0; | |
48 | #else | |
49 | # define CALCULATE_MATCH() \ | |
066020c5 RFF |
50 | vbpermq v6, v6, v10; \ |
51 | mfvrd r7, v6; \ | |
6c6ab1fc RS |
52 | addi r6, r7, -1; \ |
53 | andc r6, r6, r7; \ | |
54 | popcntd r6, r6; \ | |
55 | subfic r6, r6, 15; | |
56 | # define FIND_NULL_POS(reg) \ | |
066020c5 | 57 | vclzd v2, reg; \ |
6c6ab1fc RS |
58 | vspltb v11, v2, 7; \ |
59 | vcmpequb. v11, v11, v9; \ | |
60 | blt cr6, 1f; \ | |
61 | vsldoi v9, v0, v9, 1; \ | |
62 | vsro v2, v2, v9; \ | |
63 | 1: \ | |
64 | vsumsws v2, v2, v0; | |
65 | #endif /* !__LITTLE_ENDIAN__ */ | |
12f50337 RS |
66 | |
67 | #ifndef STRRCHR | |
68 | # define STRRCHR strrchr | |
69 | #endif | |
066020c5 | 70 | .machine power8 |
12f50337 | 71 | ENTRY_TOCLESS (STRRCHR) |
6c6ab1fc RS |
72 | CALL_MCOUNT 2 |
73 | dcbt 0,r3 | |
74 | clrrdi r8,r3,3 /* Align the address to doubleword boundary. */ | |
75 | cmpdi cr7,r4,0 | |
76 | ld r12,0(r8) /* Load doubleword from memory. */ | |
77 | li r9,0 /* Used to store last occurence. */ | |
78 | li r0,0 /* Doubleword with null chars to use | |
79 | with cmpb. */ | |
80 | ||
81 | rlwinm r6,r3,3,26,28 /* Calculate padding. */ | |
82 | ||
83 | beq cr7,L(null_match) | |
84 | ||
85 | /* Replicate byte to doubleword. */ | |
86 | insrdi r4,r4,8,48 | |
87 | insrdi r4,r4,16,32 | |
88 | insrdi r4,r4,32,0 | |
89 | ||
90 | /* r4 is changed now. If it's passed more chars, then | |
91 | check for null again. */ | |
92 | cmpdi cr7,r4,0 | |
93 | beq cr7,L(null_match) | |
94 | /* Now r4 has a doubleword of c bytes and r0 has | |
95 | a doubleword of null bytes. */ | |
96 | ||
97 | cmpb r10,r12,r4 /* Compare each byte against c byte. */ | |
98 | cmpb r11,r12,r0 /* Compare each byte against null byte. */ | |
99 | ||
100 | /* Move the doublewords left and right to discard the bits that are | |
101 | not part of the string and bring them back as zeros. */ | |
102 | #ifdef __LITTLE_ENDIAN__ | |
103 | srd r10,r10,r6 | |
104 | srd r11,r11,r6 | |
105 | sld r10,r10,r6 | |
106 | sld r11,r11,r6 | |
107 | #else | |
108 | sld r10,r10,r6 | |
109 | sld r11,r11,r6 | |
110 | srd r10,r10,r6 | |
111 | srd r11,r11,r6 | |
112 | #endif | |
113 | or r5,r10,r11 /* OR the results to speed things up. */ | |
114 | cmpdi cr7,r5,0 /* If r5 == 0, no c or null bytes | |
115 | have been found. */ | |
116 | bne cr7,L(done) | |
117 | ||
118 | L(align): | |
119 | andi. r12, r8, 15 | |
120 | ||
121 | /* Are we now aligned to a doubleword boundary? If so, skip to | |
122 | the main loop. Otherwise, go through the alignment code. */ | |
123 | ||
124 | bne cr0, L(loop) | |
125 | ||
126 | /* Handle WORD2 of pair. */ | |
127 | ldu r12,8(r8) | |
128 | cmpb r10,r12,r4 | |
129 | cmpb r11,r12,r0 | |
130 | or r5,r10,r11 | |
131 | cmpdi cr7,r5,0 | |
132 | bne cr7,L(done) | |
133 | b L(loop) /* We branch here (rather than falling through) | |
134 | to skip the nops due to heavy alignment | |
135 | of the loop below. */ | |
136 | .p2align 5 | |
137 | L(loop): | |
138 | /* Load two doublewords, compare and merge in a | |
139 | single register for speed. This is an attempt | |
140 | to speed up the null-checking process for bigger strings. */ | |
141 | ld r12,8(r8) | |
142 | ldu r7,16(r8) | |
143 | cmpb r10,r12,r4 | |
144 | cmpb r11,r12,r0 | |
145 | cmpb r6,r7,r4 | |
146 | cmpb r7,r7,r0 | |
147 | or r12,r10,r11 | |
148 | or r5,r6,r7 | |
149 | or r5,r12,r5 | |
150 | cmpdi cr7,r5,0 | |
151 | beq cr7,L(vector) | |
152 | ||
153 | /* OK, one (or both) of the doublewords contains a c/null byte. Check | |
154 | the first doubleword and decrement the address in case the first | |
155 | doubleword really contains a c/null byte. */ | |
156 | cmpdi cr6,r12,0 | |
157 | addi r8,r8,-8 | |
158 | bne cr6,L(done) | |
159 | ||
160 | /* The c/null byte must be in the second doubleword. Adjust the | |
161 | address again and move the result of cmpb to r10 so we can calculate | |
162 | the pointer. */ | |
163 | ||
164 | mr r10,r6 | |
165 | mr r11,r7 | |
166 | addi r8,r8,8 | |
167 | ||
168 | /* r10/r11 have the output of the cmpb instructions, that is, | |
169 | 0xff in the same position as the c/null byte in the original | |
170 | doubleword from the string. Use that to calculate the pointer. */ | |
171 | ||
172 | L(done): | |
173 | /* If there are more than one 0xff in r11, find the first position of | |
174 | 0xff in r11 and fill r10 with 0 from that position. */ | |
175 | cmpdi cr7,r11,0 | |
176 | beq cr7,L(no_null) | |
177 | #ifdef __LITTLE_ENDIAN__ | |
178 | addi r3,r11,-1 | |
179 | andc r3,r3,r11 | |
180 | popcntd r0,r3 | |
181 | #else | |
182 | cntlzd r0,r11 | |
183 | #endif | |
184 | subfic r0,r0,63 | |
185 | li r6,-1 | |
186 | #ifdef __LITTLE_ENDIAN__ | |
187 | srd r0,r6,r0 | |
188 | #else | |
189 | sld r0,r6,r0 | |
190 | #endif | |
191 | and r10,r0,r10 | |
192 | L(no_null): | |
193 | #ifdef __LITTLE_ENDIAN__ | |
194 | cntlzd r0,r10 /* Count leading zeros before c matches. */ | |
195 | addi r3,r10,-1 | |
196 | andc r3,r3,r10 | |
197 | addi r10,r11,-1 | |
198 | andc r10,r10,r11 | |
199 | cmpld cr7,r3,r10 | |
200 | bgt cr7,L(no_match) | |
201 | #else | |
202 | addi r3,r10,-1 /* Count trailing zeros before c matches. */ | |
203 | andc r3,r3,r10 | |
204 | popcntd r0,r3 | |
205 | cmpld cr7,r11,r10 | |
206 | bgt cr7,L(no_match) | |
207 | #endif | |
208 | srdi r0,r0,3 /* Convert trailing zeros to bytes. */ | |
209 | subfic r0,r0,7 | |
210 | add r9,r8,r0 /* Return address of the matching c byte | |
211 | or null in case c was not found. */ | |
212 | li r0,0 | |
213 | cmpdi cr7,r11,0 /* If r11 == 0, no null's have been found. */ | |
214 | beq cr7,L(align) | |
215 | ||
216 | .align 4 | |
217 | L(no_match): | |
218 | mr r3,r9 | |
219 | blr | |
220 | ||
221 | /* Check the first 32B in GPR's and move to vectorized loop. */ | |
222 | .p2align 5 | |
223 | L(vector): | |
224 | addi r3, r8, 8 | |
225 | /* Make sure 32B aligned. */ | |
226 | andi. r10, r3, 31 | |
227 | bne cr0, L(loop) | |
228 | vspltisb v0, 0 | |
229 | /* Precompute vbpermq constant. */ | |
230 | vspltisb v10, 3 | |
231 | lvsl v11, r0, r0 | |
232 | vslb v10, v11, v10 | |
066020c5 | 233 | mtvrd v1, r4 |
6c6ab1fc RS |
234 | li r5, 16 |
235 | vspltb v1, v1, 7 | |
236 | /* Compare 32 bytes in each loop. */ | |
237 | L(continue): | |
238 | lvx v4, 0, r3 | |
239 | lvx v5, r3, r5 | |
240 | vcmpequb v2, v0, v4 | |
241 | vcmpequb v3, v0, v5 | |
242 | vcmpequb v6, v1, v4 | |
243 | vcmpequb v7, v1, v5 | |
244 | vor v8, v2, v3 | |
245 | vor v9, v6, v7 | |
246 | vor v11, v8, v9 | |
247 | vcmpequb. v11, v0, v11 | |
248 | addi r3, r3, 32 | |
249 | blt cr6, L(continue) | |
250 | vcmpequb. v8, v0, v8 | |
251 | blt cr6, L(match) | |
252 | ||
253 | /* One (or both) of the quadwords contains c/null. */ | |
254 | vspltisb v8, 2 | |
255 | vspltisb v9, 5 | |
256 | /* Precompute values used for comparison. */ | |
257 | vsl v9, v8, v9 /* v9 = 0x4040404040404040. */ | |
258 | vaddubm v8, v9, v9 | |
259 | vsldoi v8, v0, v8, 1 /* v8 = 0x80. */ | |
260 | ||
261 | /* Check if null is in second qw. */ | |
262 | vcmpequb. v11, v0, v2 | |
263 | blt cr6, L(secondqw) | |
264 | ||
265 | /* Null found in first qw. */ | |
266 | addi r8, r3, -32 | |
267 | /* Calculate the null position. */ | |
268 | FIND_NULL_POS(v2) | |
269 | /* Check if null is in the first byte. */ | |
270 | vcmpequb. v11, v0, v2 | |
271 | blt cr6, L(no_match) | |
272 | vsububm v2, v8, v2 | |
273 | /* Mask unwanted bytes after null. */ | |
274 | #ifdef __LITTLE_ENDIAN__ | |
275 | vslo v6, v6, v2 | |
276 | vsro v6, v6, v2 | |
277 | #else | |
278 | vsro v6, v6, v2 | |
279 | vslo v6, v6, v2 | |
280 | #endif | |
281 | vcmpequb. v11, v0, v6 | |
282 | blt cr6, L(no_match) | |
283 | /* Found a match before null. */ | |
284 | CALCULATE_MATCH() | |
285 | add r3, r8, r6 | |
286 | blr | |
287 | ||
288 | L(secondqw): | |
289 | addi r8, r3, -16 | |
290 | FIND_NULL_POS(v3) | |
291 | vcmpequb. v11, v0, v2 | |
292 | blt cr6, L(no_match1) | |
293 | vsububm v2, v8, v2 | |
294 | /* Mask unwanted bytes after null. */ | |
295 | #ifdef __LITTLE_ENDIAN__ | |
296 | vslo v7, v7, v2 | |
297 | vsro v7, v7, v2 | |
298 | #else | |
299 | vsro v7, v7, v2 | |
300 | vslo v7, v7, v2 | |
301 | #endif | |
302 | vcmpequb. v11, v0, v7 | |
303 | blt cr6, L(no_match1) | |
304 | addi r8, r8, 16 | |
305 | vor v6, v0, v7 | |
306 | L(no_match1): | |
307 | addi r8, r8, -16 | |
308 | vcmpequb. v11, v0, v6 | |
309 | blt cr6, L(no_match) | |
310 | /* Found a match before null. */ | |
311 | CALCULATE_MATCH() | |
312 | add r3, r8, r6 | |
313 | blr | |
314 | ||
315 | L(match): | |
316 | /* One (or both) of the quadwords contains a match. */ | |
317 | mr r8, r3 | |
318 | vcmpequb. v8, v0, v7 | |
319 | blt cr6, L(firstqw) | |
320 | /* Match found in second qw. */ | |
321 | addi r8, r8, 16 | |
322 | vor v6, v0, v7 | |
323 | L(firstqw): | |
324 | addi r8, r8, -32 | |
325 | CALCULATE_MATCH() | |
326 | add r9, r8, r6 /* Compute final length. */ | |
327 | b L(continue) | |
328 | /* We are here because strrchr was called with a null byte. */ | |
329 | .align 4 | |
330 | L(null_match): | |
331 | /* r0 has a doubleword of null bytes. */ | |
332 | ||
333 | cmpb r5,r12,r0 /* Compare each byte against null bytes. */ | |
334 | ||
335 | /* Move the doublewords left and right to discard the bits that are | |
336 | not part of the string and bring them back as zeros. */ | |
337 | #ifdef __LITTLE_ENDIAN__ | |
338 | srd r5,r5,r6 | |
339 | sld r5,r5,r6 | |
340 | #else | |
341 | sld r5,r5,r6 | |
342 | srd r5,r5,r6 | |
343 | #endif | |
344 | cmpdi cr7,r5,0 /* If r5 == 0, no c or null bytes | |
345 | have been found. */ | |
346 | bne cr7,L(done_null) | |
347 | ||
348 | andi. r12, r8, 15 | |
349 | ||
350 | /* Are we now aligned to a quadword boundary? If so, skip to | |
351 | the main loop. Otherwise, go through the alignment code. */ | |
352 | ||
353 | bne cr0, L(loop_null) | |
354 | ||
355 | /* Handle WORD2 of pair. */ | |
356 | ldu r12,8(r8) | |
357 | cmpb r5,r12,r0 | |
358 | cmpdi cr7,r5,0 | |
359 | bne cr7,L(done_null) | |
360 | b L(loop_null) /* We branch here (rather than falling through) | |
361 | to skip the nops due to heavy alignment | |
362 | of the loop below. */ | |
363 | ||
364 | /* Main loop to look for the end of the string. Since it's a | |
365 | small loop (< 8 instructions), align it to 32-bytes. */ | |
366 | .p2align 5 | |
367 | L(loop_null): | |
368 | /* Load two doublewords, compare and merge in a | |
369 | single register for speed. This is an attempt | |
370 | to speed up the null-checking process for bigger strings. */ | |
371 | ld r12,8(r8) | |
372 | ldu r11,16(r8) | |
373 | cmpb r5,r12,r0 | |
374 | cmpb r10,r11,r0 | |
375 | or r6,r5,r10 | |
376 | cmpdi cr7,r6,0 | |
377 | beq cr7,L(vector1) | |
378 | ||
379 | /* OK, one (or both) of the doublewords contains a null byte. Check | |
380 | the first doubleword and decrement the address in case the first | |
381 | doubleword really contains a null byte. */ | |
382 | ||
383 | cmpdi cr6,r5,0 | |
384 | addi r8,r8,-8 | |
385 | bne cr6,L(done_null) | |
386 | ||
387 | /* The null byte must be in the second doubleword. Adjust the address | |
388 | again and move the result of cmpb to r10 so we can calculate the | |
389 | pointer. */ | |
390 | ||
391 | mr r5,r10 | |
392 | addi r8,r8,8 | |
393 | ||
394 | /* r5 has the output of the cmpb instruction, that is, it contains | |
395 | 0xff in the same position as the null byte in the original | |
396 | doubleword from the string. Use that to calculate the pointer. */ | |
397 | L(done_null): | |
398 | #ifdef __LITTLE_ENDIAN__ | |
399 | addi r0,r5,-1 | |
400 | andc r0,r0,r5 | |
401 | popcntd r0,r0 | |
402 | #else | |
403 | cntlzd r0,r5 /* Count leading zeros before the match. */ | |
404 | #endif | |
405 | srdi r0,r0,3 /* Convert trailing zeros to bytes. */ | |
406 | add r3,r8,r0 /* Return address of the matching null byte. */ | |
407 | blr | |
408 | /* Check the first 32B in GPR's and move to vectorized loop. */ | |
409 | .p2align 5 | |
410 | L(vector1): | |
411 | addi r3, r8, 8 | |
412 | /* Make sure 32B aligned. */ | |
413 | andi. r10, r3, 31 | |
414 | bne cr0, L(loop_null) | |
415 | vspltisb v0, 0 | |
416 | /* Precompute vbpermq constant. */ | |
417 | vspltisb v10, 3 | |
418 | lvsl v11, r0, r0 | |
419 | vslb v10, v11, v10 | |
420 | li r5, 16 | |
421 | /* Compare 32 bytes in each loop. */ | |
422 | L(continue1): | |
423 | lvx v4, 0, r3 | |
424 | lvx v5, r3, r5 | |
425 | vcmpequb v2, v0, v4 | |
426 | vcmpequb v3, v0, v5 | |
427 | vor v8, v2, v3 | |
428 | vcmpequb. v11, v0, v8 | |
429 | addi r3, r3, 32 | |
430 | blt cr6, L(continue1) | |
431 | addi r3, r3, -32 | |
066020c5 RFF |
432 | vbpermq v2, v2, v10 |
433 | vbpermq v3, v3, v10 | |
6c6ab1fc RS |
434 | /* Shift each component into its correct position for merging. */ |
435 | #ifdef __LITTLE_ENDIAN__ | |
436 | vsldoi v3, v3, v3, 2 | |
437 | #else | |
438 | vsldoi v2, v2, v2, 6 | |
439 | vsldoi v3, v3, v3, 4 | |
440 | #endif | |
441 | /* Merge the results and move to a GPR. */ | |
442 | vor v4, v3, v2 | |
066020c5 | 443 | mfvrd r5, v4 |
6c6ab1fc RS |
444 | #ifdef __LITTLE_ENDIAN__ |
445 | addi r6, r5, -1 | |
446 | andc r6, r6, r5 | |
447 | popcntd r6, r6 | |
448 | #else | |
449 | cntlzd r6, r5 /* Count leading zeros before the match. */ | |
450 | #endif | |
451 | add r3, r3, r6 /* Compute final length. */ | |
452 | blr | |
12f50337 | 453 | END_GEN_TB (STRRCHR, TB_TOCLESS) |
6c6ab1fc RS |
454 | weak_alias (strrchr, rindex) |
455 | libc_hidden_builtin_def (strrchr) |