| blob | 582d817979ed51c79219014864869da96bb5a294 |
1 /*
2 * arch/xtensa/lib/hal/memcopy.S -- Core HAL library functions
3 * xthal_memcpy and xthal_bcopy
4 *
5 * This file is subject to the terms and conditions of the GNU General Public
6 * License. See the file "COPYING" in the main directory of this archive
7 * for more details.
8 *
9 * Copyright (C) 2002 - 2012 Tensilica Inc.
10 */
12 #include <linux/linkage.h>
13 #include <asm/asmmacro.h>
14 #include <asm/core.h>
16 /*
17 * void *memcpy(void *dst, const void *src, size_t len);
18 *
19 * This function is intended to do the same thing as the standard
20 * library function memcpy() for most cases.
21 * However, where the source and/or destination references
22 * an instruction RAM or ROM or a data RAM or ROM, that
23 * source and/or destination will always be accessed with
24 * 32-bit load and store instructions (as required for these
25 * types of devices).
26 *
27 * !!!!!!! XTFIXME:
28 * !!!!!!! Handling of IRAM/IROM has not yet
29 * !!!!!!! been implemented.
30 *
31 * The (general case) algorithm is as follows:
32 * If destination is unaligned, align it by conditionally
33 * copying 1 and 2 bytes.
34 * If source is aligned,
35 * do 16 bytes with a loop, and then finish up with
36 * 8, 4, 2, and 1 byte copies conditional on the length;
37 * else (if source is unaligned),
38 * do the same, but use SRC to align the source data.
39 * This code tries to use fall-through branches for the common
40 * case of aligned source and destination and multiple
41 * of 4 (or 8) length.
42 *
43 * Register use:
44 * a0/ return address
45 * a1/ stack pointer
46 * a2/ return value
47 * a3/ src
48 * a4/ length
49 * a5/ dst
50 * a6/ tmp
51 * a7/ tmp
52 * a8/ tmp
53 * a9/ tmp
54 * a10/ tmp
55 * a11/ tmp
56 */
58 .text
60 /*
61 * Byte by byte copy
62 */
63 .align 4
64 .byte 0 # 1 mod 4 alignment for LOOPNEZ
65 # (0 mod 4 alignment for LBEG)
66 .Lbytecopy:
67 #if XCHAL_HAVE_LOOPS
68 loopnez a4, .Lbytecopydone
69 #else /* !XCHAL_HAVE_LOOPS */
70 beqz a4, .Lbytecopydone
71 add a7, a3, a4 # a7 = end address for source
72 #endif /* !XCHAL_HAVE_LOOPS */
73 .Lnextbyte:
74 l8ui a6, a3, 0
75 addi a3, a3, 1
76 s8i a6, a5, 0
77 addi a5, a5, 1
78 #if !XCHAL_HAVE_LOOPS
79 bne a3, a7, .Lnextbyte # continue loop if $a3:src != $a7:src_end
80 #endif /* !XCHAL_HAVE_LOOPS */
81 .Lbytecopydone:
82 abi_ret_default
84 /*
85 * Destination is unaligned
86 */
88 .align 4
89 .Ldst1mod2: # dst is only byte aligned
90 _bltui a4, 7, .Lbytecopy # do short copies byte by byte
92 # copy 1 byte
93 l8ui a6, a3, 0
94 addi a3, a3, 1
95 addi a4, a4, -1
96 s8i a6, a5, 0
97 addi a5, a5, 1
98 _bbci.l a5, 1, .Ldstaligned # if dst is now aligned, then
99 # return to main algorithm
100 .Ldst2mod4: # dst 16-bit aligned
101 # copy 2 bytes
102 _bltui a4, 6, .Lbytecopy # do short copies byte by byte
103 l8ui a6, a3, 0
104 l8ui a7, a3, 1
105 addi a3, a3, 2
106 addi a4, a4, -2
107 s8i a6, a5, 0
108 s8i a7, a5, 1
109 addi a5, a5, 2
110 j .Ldstaligned # dst is now aligned, return to main algorithm
112 ENTRY(__memcpy)
113 WEAK(memcpy)
115 abi_entry_default
116 # a2/ dst, a3/ src, a4/ len
117 mov a5, a2 # copy dst so that a2 is return value
118 .Lcommon:
119 _bbsi.l a2, 0, .Ldst1mod2 # if dst is 1 mod 2
120 _bbsi.l a2, 1, .Ldst2mod4 # if dst is 2 mod 4
121 .Ldstaligned: # return here from .Ldst?mod? once dst is aligned
122 srli a7, a4, 4 # number of loop iterations with 16B
123 # per iteration
124 movi a8, 3 # if source is not aligned,
125 _bany a3, a8, .Lsrcunaligned # then use shifting copy
126 /*
127 * Destination and source are word-aligned, use word copy.
128 */
129 # copy 16 bytes per iteration for word-aligned dst and word-aligned src
130 #if XCHAL_HAVE_LOOPS
131 loopnez a7, .Loop1done
132 #else /* !XCHAL_HAVE_LOOPS */
133 beqz a7, .Loop1done
134 slli a8, a7, 4
135 add a8, a8, a3 # a8 = end of last 16B source chunk
136 #endif /* !XCHAL_HAVE_LOOPS */
137 .Loop1:
138 l32i a6, a3, 0
139 l32i a7, a3, 4
140 s32i a6, a5, 0
141 l32i a6, a3, 8
142 s32i a7, a5, 4
143 l32i a7, a3, 12
144 s32i a6, a5, 8
145 addi a3, a3, 16
146 s32i a7, a5, 12
147 addi a5, a5, 16
148 #if !XCHAL_HAVE_LOOPS
149 bne a3, a8, .Loop1 # continue loop if a3:src != a8:src_end
150 #endif /* !XCHAL_HAVE_LOOPS */
151 .Loop1done:
152 bbci.l a4, 3, .L2
153 # copy 8 bytes
154 l32i a6, a3, 0
155 l32i a7, a3, 4
156 addi a3, a3, 8
157 s32i a6, a5, 0
158 s32i a7, a5, 4
159 addi a5, a5, 8
160 .L2:
161 bbsi.l a4, 2, .L3
162 bbsi.l a4, 1, .L4
163 bbsi.l a4, 0, .L5
164 abi_ret_default
165 .L3:
166 # copy 4 bytes
167 l32i a6, a3, 0
168 addi a3, a3, 4
169 s32i a6, a5, 0
170 addi a5, a5, 4
171 bbsi.l a4, 1, .L4
172 bbsi.l a4, 0, .L5
173 abi_ret_default
174 .L4:
175 # copy 2 bytes
176 l16ui a6, a3, 0
177 addi a3, a3, 2
178 s16i a6, a5, 0
179 addi a5, a5, 2
180 bbsi.l a4, 0, .L5
181 abi_ret_default
182 .L5:
183 # copy 1 byte
184 l8ui a6, a3, 0
185 s8i a6, a5, 0
186 abi_ret_default
188 /*
189 * Destination is aligned, Source is unaligned
190 */
192 .align 4
193 .Lsrcunaligned:
194 _beqz a4, .Ldone # avoid loading anything for zero-length copies
195 # copy 16 bytes per iteration for word-aligned dst and unaligned src
196 __ssa8 a3 # set shift amount from byte offset
198 /* set to 1 when running on ISS (simulator) with the
199 lint or ferret client, or 0 to save a few cycles */
200 #define SIM_CHECKS_ALIGNMENT 1
201 #if XCHAL_UNALIGNED_LOAD_EXCEPTION || SIM_CHECKS_ALIGNMENT
202 and a11, a3, a8 # save unalignment offset for below
203 sub a3, a3, a11 # align a3
204 #endif
205 l32i a6, a3, 0 # load first word
206 #if XCHAL_HAVE_LOOPS
207 loopnez a7, .Loop2done
208 #else /* !XCHAL_HAVE_LOOPS */
209 beqz a7, .Loop2done
210 slli a10, a7, 4
211 add a10, a10, a3 # a10 = end of last 16B source chunk
212 #endif /* !XCHAL_HAVE_LOOPS */
213 .Loop2:
214 l32i a7, a3, 4
215 l32i a8, a3, 8
216 __src_b a6, a6, a7
217 s32i a6, a5, 0
218 l32i a9, a3, 12
219 __src_b a7, a7, a8
220 s32i a7, a5, 4
221 l32i a6, a3, 16
222 __src_b a8, a8, a9
223 s32i a8, a5, 8
224 addi a3, a3, 16
225 __src_b a9, a9, a6
226 s32i a9, a5, 12
227 addi a5, a5, 16
228 #if !XCHAL_HAVE_LOOPS
229 bne a3, a10, .Loop2 # continue loop if a3:src != a10:src_end
230 #endif /* !XCHAL_HAVE_LOOPS */
231 .Loop2done:
232 bbci.l a4, 3, .L12
233 # copy 8 bytes
234 l32i a7, a3, 4
235 l32i a8, a3, 8
236 __src_b a6, a6, a7
237 s32i a6, a5, 0
238 addi a3, a3, 8
239 __src_b a7, a7, a8
240 s32i a7, a5, 4
241 addi a5, a5, 8
242 mov a6, a8
243 .L12:
244 bbci.l a4, 2, .L13
245 # copy 4 bytes
246 l32i a7, a3, 4
247 addi a3, a3, 4
248 __src_b a6, a6, a7
249 s32i a6, a5, 0
250 addi a5, a5, 4
251 mov a6, a7
252 .L13:
253 #if XCHAL_UNALIGNED_LOAD_EXCEPTION || SIM_CHECKS_ALIGNMENT
254 add a3, a3, a11 # readjust a3 with correct misalignment
255 #endif
256 bbsi.l a4, 1, .L14
257 bbsi.l a4, 0, .L15
258 .Ldone: abi_ret_default
259 .L14:
260 # copy 2 bytes
261 l8ui a6, a3, 0
262 l8ui a7, a3, 1
263 addi a3, a3, 2
264 s8i a6, a5, 0
265 s8i a7, a5, 1
266 addi a5, a5, 2
267 bbsi.l a4, 0, .L15
268 abi_ret_default
269 .L15:
270 # copy 1 byte
271 l8ui a6, a3, 0
272 s8i a6, a5, 0
273 abi_ret_default
275 ENDPROC(__memcpy)
277 /*
278 * void bcopy(const void *src, void *dest, size_t n);
279 */
281 ENTRY(bcopy)
283 abi_entry_default
284 # a2=src, a3=dst, a4=len
285 mov a5, a3
286 mov a3, a2
287 mov a2, a5
288 j .Lmovecommon # go to common code for memmove+bcopy
290 ENDPROC(bcopy)
292 /*
293 * void *memmove(void *dst, const void *src, size_t len);
294 *
295 * This function is intended to do the same thing as the standard
296 * library function memmove() for most cases.
297 * However, where the source and/or destination references
298 * an instruction RAM or ROM or a data RAM or ROM, that
299 * source and/or destination will always be accessed with
300 * 32-bit load and store instructions (as required for these
301 * types of devices).
302 *
303 * !!!!!!! XTFIXME:
304 * !!!!!!! Handling of IRAM/IROM has not yet
305 * !!!!!!! been implemented.
306 *
307 * The (general case) algorithm is as follows:
308 * If end of source doesn't overlap destination then use memcpy.
309 * Otherwise do memcpy backwards.
310 *
311 * Register use:
312 * a0/ return address
313 * a1/ stack pointer
314 * a2/ return value
315 * a3/ src
316 * a4/ length
317 * a5/ dst
318 * a6/ tmp
319 * a7/ tmp
320 * a8/ tmp
321 * a9/ tmp
322 * a10/ tmp
323 * a11/ tmp
324 */
326 /*
327 * Byte by byte copy
328 */
329 .align 4
330 .byte 0 # 1 mod 4 alignment for LOOPNEZ
331 # (0 mod 4 alignment for LBEG)
332 .Lbackbytecopy:
333 #if XCHAL_HAVE_LOOPS
334 loopnez a4, .Lbackbytecopydone
335 #else /* !XCHAL_HAVE_LOOPS */
336 beqz a4, .Lbackbytecopydone
337 sub a7, a3, a4 # a7 = start address for source
338 #endif /* !XCHAL_HAVE_LOOPS */
339 .Lbacknextbyte:
340 addi a3, a3, -1
341 l8ui a6, a3, 0
342 addi a5, a5, -1
343 s8i a6, a5, 0
344 #if !XCHAL_HAVE_LOOPS
345 bne a3, a7, .Lbacknextbyte # continue loop if
346 # $a3:src != $a7:src_start
347 #endif /* !XCHAL_HAVE_LOOPS */
348 .Lbackbytecopydone:
349 abi_ret_default
351 /*
352 * Destination is unaligned
353 */
355 .align 4
356 .Lbackdst1mod2: # dst is only byte aligned
357 _bltui a4, 7, .Lbackbytecopy # do short copies byte by byte
359 # copy 1 byte
360 addi a3, a3, -1
361 l8ui a6, a3, 0
362 addi a5, a5, -1
363 s8i a6, a5, 0
364 addi a4, a4, -1
365 _bbci.l a5, 1, .Lbackdstaligned # if dst is now aligned, then
366 # return to main algorithm
367 .Lbackdst2mod4: # dst 16-bit aligned
368 # copy 2 bytes
369 _bltui a4, 6, .Lbackbytecopy # do short copies byte by byte
370 addi a3, a3, -2
371 l8ui a6, a3, 0
372 l8ui a7, a3, 1
373 addi a5, a5, -2
374 s8i a6, a5, 0
375 s8i a7, a5, 1
376 addi a4, a4, -2
377 j .Lbackdstaligned # dst is now aligned,
378 # return to main algorithm
380 ENTRY(__memmove)
381 WEAK(memmove)
383 abi_entry_default
384 # a2/ dst, a3/ src, a4/ len
385 mov a5, a2 # copy dst so that a2 is return value
386 .Lmovecommon:
387 sub a6, a5, a3
388 bgeu a6, a4, .Lcommon
390 add a5, a5, a4
391 add a3, a3, a4
393 _bbsi.l a5, 0, .Lbackdst1mod2 # if dst is 1 mod 2
394 _bbsi.l a5, 1, .Lbackdst2mod4 # if dst is 2 mod 4
395 .Lbackdstaligned: # return here from .Lbackdst?mod? once dst is aligned
396 srli a7, a4, 4 # number of loop iterations with 16B
397 # per iteration
398 movi a8, 3 # if source is not aligned,
399 _bany a3, a8, .Lbacksrcunaligned # then use shifting copy
400 /*
401 * Destination and source are word-aligned, use word copy.
402 */
403 # copy 16 bytes per iteration for word-aligned dst and word-aligned src
404 #if XCHAL_HAVE_LOOPS
405 loopnez a7, .backLoop1done
406 #else /* !XCHAL_HAVE_LOOPS */
407 beqz a7, .backLoop1done
408 slli a8, a7, 4
409 sub a8, a3, a8 # a8 = start of first 16B source chunk
410 #endif /* !XCHAL_HAVE_LOOPS */
411 .backLoop1:
412 addi a3, a3, -16
413 l32i a7, a3, 12
414 l32i a6, a3, 8
415 addi a5, a5, -16
416 s32i a7, a5, 12
417 l32i a7, a3, 4
418 s32i a6, a5, 8
419 l32i a6, a3, 0
420 s32i a7, a5, 4
421 s32i a6, a5, 0
422 #if !XCHAL_HAVE_LOOPS
423 bne a3, a8, .backLoop1 # continue loop if a3:src != a8:src_start
424 #endif /* !XCHAL_HAVE_LOOPS */
425 .backLoop1done:
426 bbci.l a4, 3, .Lback2
427 # copy 8 bytes
428 addi a3, a3, -8
429 l32i a6, a3, 0
430 l32i a7, a3, 4
431 addi a5, a5, -8
432 s32i a6, a5, 0
433 s32i a7, a5, 4
434 .Lback2:
435 bbsi.l a4, 2, .Lback3
436 bbsi.l a4, 1, .Lback4
437 bbsi.l a4, 0, .Lback5
438 abi_ret_default
439 .Lback3:
440 # copy 4 bytes
441 addi a3, a3, -4
442 l32i a6, a3, 0
443 addi a5, a5, -4
444 s32i a6, a5, 0
445 bbsi.l a4, 1, .Lback4
446 bbsi.l a4, 0, .Lback5
447 abi_ret_default
448 .Lback4:
449 # copy 2 bytes
450 addi a3, a3, -2
451 l16ui a6, a3, 0
452 addi a5, a5, -2
453 s16i a6, a5, 0
454 bbsi.l a4, 0, .Lback5
455 abi_ret_default
456 .Lback5:
457 # copy 1 byte
458 addi a3, a3, -1
459 l8ui a6, a3, 0
460 addi a5, a5, -1
461 s8i a6, a5, 0
462 abi_ret_default
464 /*
465 * Destination is aligned, Source is unaligned
466 */
468 .align 4
469 .Lbacksrcunaligned:
470 _beqz a4, .Lbackdone # avoid loading anything for zero-length copies
471 # copy 16 bytes per iteration for word-aligned dst and unaligned src
472 __ssa8 a3 # set shift amount from byte offset
473 #define SIM_CHECKS_ALIGNMENT 1 /* set to 1 when running on ISS with
474 * the lint or ferret client, or 0
475 * to save a few cycles */
476 #if XCHAL_UNALIGNED_LOAD_EXCEPTION || SIM_CHECKS_ALIGNMENT
477 and a11, a3, a8 # save unalignment offset for below
478 sub a3, a3, a11 # align a3
479 #endif
480 l32i a6, a3, 0 # load first word
481 #if XCHAL_HAVE_LOOPS
482 loopnez a7, .backLoop2done
483 #else /* !XCHAL_HAVE_LOOPS */
484 beqz a7, .backLoop2done
485 slli a10, a7, 4
486 sub a10, a3, a10 # a10 = start of first 16B source chunk
487 #endif /* !XCHAL_HAVE_LOOPS */
488 .backLoop2:
489 addi a3, a3, -16
490 l32i a7, a3, 12
491 l32i a8, a3, 8
492 addi a5, a5, -16
493 __src_b a6, a7, a6
494 s32i a6, a5, 12
495 l32i a9, a3, 4
496 __src_b a7, a8, a7
497 s32i a7, a5, 8
498 l32i a6, a3, 0
499 __src_b a8, a9, a8
500 s32i a8, a5, 4
501 __src_b a9, a6, a9
502 s32i a9, a5, 0
503 #if !XCHAL_HAVE_LOOPS
504 bne a3, a10, .backLoop2 # continue loop if a3:src != a10:src_start
505 #endif /* !XCHAL_HAVE_LOOPS */
506 .backLoop2done:
507 bbci.l a4, 3, .Lback12
508 # copy 8 bytes
509 addi a3, a3, -8
510 l32i a7, a3, 4
511 l32i a8, a3, 0
512 addi a5, a5, -8
513 __src_b a6, a7, a6
514 s32i a6, a5, 4
515 __src_b a7, a8, a7
516 s32i a7, a5, 0
517 mov a6, a8
518 .Lback12:
519 bbci.l a4, 2, .Lback13
520 # copy 4 bytes
521 addi a3, a3, -4
522 l32i a7, a3, 0
523 addi a5, a5, -4
524 __src_b a6, a7, a6
525 s32i a6, a5, 0
526 mov a6, a7
527 .Lback13:
528 #if XCHAL_UNALIGNED_LOAD_EXCEPTION || SIM_CHECKS_ALIGNMENT
529 add a3, a3, a11 # readjust a3 with correct misalignment
530 #endif
531 bbsi.l a4, 1, .Lback14
532 bbsi.l a4, 0, .Lback15
533 .Lbackdone:
534 abi_ret_default
535 .Lback14:
536 # copy 2 bytes
537 addi a3, a3, -2
538 l8ui a6, a3, 0
539 l8ui a7, a3, 1
540 addi a5, a5, -2
541 s8i a6, a5, 0
542 s8i a7, a5, 1
543 bbsi.l a4, 0, .Lback15
544 abi_ret_default
545 .Lback15:
546 # copy 1 byte
547 addi a3, a3, -1
548 addi a5, a5, -1
549 l8ui a6, a3, 0
550 s8i a6, a5, 0
551 abi_ret_default
553 ENDPROC(__memmove)