Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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 */
11
12#include <linux/linkage.h>
13#include <asm/asmmacro.h>
14#include <asm/core.h>
15
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 */
57
58 .text
59
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
83
84/*
85 * Destination is unaligned
86 */
87
88 .align 4
89.Ldst1mod2: # dst is only byte aligned
90 _bltui a4, 7, .Lbytecopy # do short copies byte by byte
91
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
111
112ENTRY(__memcpy)
113WEAK(memcpy)
114
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
187
188/*
189 * Destination is aligned, Source is unaligned
190 */
191
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
197
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
274
275ENDPROC(__memcpy)
276EXPORT_SYMBOL(__memcpy)
277EXPORT_SYMBOL(memcpy)
278
279/*
280 * void *memmove(void *dst, const void *src, size_t len);
281 *
282 * This function is intended to do the same thing as the standard
283 * library function memmove() for most cases.
284 * However, where the source and/or destination references
285 * an instruction RAM or ROM or a data RAM or ROM, that
286 * source and/or destination will always be accessed with
287 * 32-bit load and store instructions (as required for these
288 * types of devices).
289 *
290 * !!!!!!! XTFIXME:
291 * !!!!!!! Handling of IRAM/IROM has not yet
292 * !!!!!!! been implemented.
293 *
294 * The (general case) algorithm is as follows:
295 * If end of source doesn't overlap destination then use memcpy.
296 * Otherwise do memcpy backwards.
297 *
298 * Register use:
299 * a0/ return address
300 * a1/ stack pointer
301 * a2/ return value
302 * a3/ src
303 * a4/ length
304 * a5/ dst
305 * a6/ tmp
306 * a7/ tmp
307 * a8/ tmp
308 * a9/ tmp
309 * a10/ tmp
310 * a11/ tmp
311 */
312
313/*
314 * Byte by byte copy
315 */
316 .align 4
317 .byte 0 # 1 mod 4 alignment for LOOPNEZ
318 # (0 mod 4 alignment for LBEG)
319.Lbackbytecopy:
320#if XCHAL_HAVE_LOOPS
321 loopnez a4, .Lbackbytecopydone
322#else /* !XCHAL_HAVE_LOOPS */
323 beqz a4, .Lbackbytecopydone
324 sub a7, a3, a4 # a7 = start address for source
325#endif /* !XCHAL_HAVE_LOOPS */
326.Lbacknextbyte:
327 addi a3, a3, -1
328 l8ui a6, a3, 0
329 addi a5, a5, -1
330 s8i a6, a5, 0
331#if !XCHAL_HAVE_LOOPS
332 bne a3, a7, .Lbacknextbyte # continue loop if
333 # $a3:src != $a7:src_start
334#endif /* !XCHAL_HAVE_LOOPS */
335.Lbackbytecopydone:
336 abi_ret_default
337
338/*
339 * Destination is unaligned
340 */
341
342 .align 4
343.Lbackdst1mod2: # dst is only byte aligned
344 _bltui a4, 7, .Lbackbytecopy # do short copies byte by byte
345
346 # copy 1 byte
347 addi a3, a3, -1
348 l8ui a6, a3, 0
349 addi a5, a5, -1
350 s8i a6, a5, 0
351 addi a4, a4, -1
352 _bbci.l a5, 1, .Lbackdstaligned # if dst is now aligned, then
353 # return to main algorithm
354.Lbackdst2mod4: # dst 16-bit aligned
355 # copy 2 bytes
356 _bltui a4, 6, .Lbackbytecopy # do short copies byte by byte
357 addi a3, a3, -2
358 l8ui a6, a3, 0
359 l8ui a7, a3, 1
360 addi a5, a5, -2
361 s8i a6, a5, 0
362 s8i a7, a5, 1
363 addi a4, a4, -2
364 j .Lbackdstaligned # dst is now aligned,
365 # return to main algorithm
366
367ENTRY(__memmove)
368WEAK(memmove)
369
370 abi_entry_default
371 # a2/ dst, a3/ src, a4/ len
372 mov a5, a2 # copy dst so that a2 is return value
373.Lmovecommon:
374 sub a6, a5, a3
375 bgeu a6, a4, .Lcommon
376
377 add a5, a5, a4
378 add a3, a3, a4
379
380 _bbsi.l a5, 0, .Lbackdst1mod2 # if dst is 1 mod 2
381 _bbsi.l a5, 1, .Lbackdst2mod4 # if dst is 2 mod 4
382.Lbackdstaligned: # return here from .Lbackdst?mod? once dst is aligned
383 srli a7, a4, 4 # number of loop iterations with 16B
384 # per iteration
385 movi a8, 3 # if source is not aligned,
386 _bany a3, a8, .Lbacksrcunaligned # then use shifting copy
387 /*
388 * Destination and source are word-aligned, use word copy.
389 */
390 # copy 16 bytes per iteration for word-aligned dst and word-aligned src
391#if XCHAL_HAVE_LOOPS
392 loopnez a7, .LbackLoop1done
393#else /* !XCHAL_HAVE_LOOPS */
394 beqz a7, .LbackLoop1done
395 slli a8, a7, 4
396 sub a8, a3, a8 # a8 = start of first 16B source chunk
397#endif /* !XCHAL_HAVE_LOOPS */
398.LbackLoop1:
399 addi a3, a3, -16
400 l32i a7, a3, 12
401 l32i a6, a3, 8
402 addi a5, a5, -16
403 s32i a7, a5, 12
404 l32i a7, a3, 4
405 s32i a6, a5, 8
406 l32i a6, a3, 0
407 s32i a7, a5, 4
408 s32i a6, a5, 0
409#if !XCHAL_HAVE_LOOPS
410 bne a3, a8, .LbackLoop1 # continue loop if a3:src != a8:src_start
411#endif /* !XCHAL_HAVE_LOOPS */
412.LbackLoop1done:
413 bbci.l a4, 3, .Lback2
414 # copy 8 bytes
415 addi a3, a3, -8
416 l32i a6, a3, 0
417 l32i a7, a3, 4
418 addi a5, a5, -8
419 s32i a6, a5, 0
420 s32i a7, a5, 4
421.Lback2:
422 bbsi.l a4, 2, .Lback3
423 bbsi.l a4, 1, .Lback4
424 bbsi.l a4, 0, .Lback5
425 abi_ret_default
426.Lback3:
427 # copy 4 bytes
428 addi a3, a3, -4
429 l32i a6, a3, 0
430 addi a5, a5, -4
431 s32i a6, a5, 0
432 bbsi.l a4, 1, .Lback4
433 bbsi.l a4, 0, .Lback5
434 abi_ret_default
435.Lback4:
436 # copy 2 bytes
437 addi a3, a3, -2
438 l16ui a6, a3, 0
439 addi a5, a5, -2
440 s16i a6, a5, 0
441 bbsi.l a4, 0, .Lback5
442 abi_ret_default
443.Lback5:
444 # copy 1 byte
445 addi a3, a3, -1
446 l8ui a6, a3, 0
447 addi a5, a5, -1
448 s8i a6, a5, 0
449 abi_ret_default
450
451/*
452 * Destination is aligned, Source is unaligned
453 */
454
455 .align 4
456.Lbacksrcunaligned:
457 _beqz a4, .Lbackdone # avoid loading anything for zero-length copies
458 # copy 16 bytes per iteration for word-aligned dst and unaligned src
459 __ssa8 a3 # set shift amount from byte offset
460#define SIM_CHECKS_ALIGNMENT 1 /* set to 1 when running on ISS with
461 * the lint or ferret client, or 0
462 * to save a few cycles */
463#if XCHAL_UNALIGNED_LOAD_EXCEPTION || SIM_CHECKS_ALIGNMENT
464 and a11, a3, a8 # save unalignment offset for below
465 sub a3, a3, a11 # align a3
466#endif
467 l32i a6, a3, 0 # load first word
468#if XCHAL_HAVE_LOOPS
469 loopnez a7, .LbackLoop2done
470#else /* !XCHAL_HAVE_LOOPS */
471 beqz a7, .LbackLoop2done
472 slli a10, a7, 4
473 sub a10, a3, a10 # a10 = start of first 16B source chunk
474#endif /* !XCHAL_HAVE_LOOPS */
475.LbackLoop2:
476 addi a3, a3, -16
477 l32i a7, a3, 12
478 l32i a8, a3, 8
479 addi a5, a5, -16
480 __src_b a6, a7, a6
481 s32i a6, a5, 12
482 l32i a9, a3, 4
483 __src_b a7, a8, a7
484 s32i a7, a5, 8
485 l32i a6, a3, 0
486 __src_b a8, a9, a8
487 s32i a8, a5, 4
488 __src_b a9, a6, a9
489 s32i a9, a5, 0
490#if !XCHAL_HAVE_LOOPS
491 bne a3, a10, .LbackLoop2 # continue loop if a3:src != a10:src_start
492#endif /* !XCHAL_HAVE_LOOPS */
493.LbackLoop2done:
494 bbci.l a4, 3, .Lback12
495 # copy 8 bytes
496 addi a3, a3, -8
497 l32i a7, a3, 4
498 l32i a8, a3, 0
499 addi a5, a5, -8
500 __src_b a6, a7, a6
501 s32i a6, a5, 4
502 __src_b a7, a8, a7
503 s32i a7, a5, 0
504 mov a6, a8
505.Lback12:
506 bbci.l a4, 2, .Lback13
507 # copy 4 bytes
508 addi a3, a3, -4
509 l32i a7, a3, 0
510 addi a5, a5, -4
511 __src_b a6, a7, a6
512 s32i a6, a5, 0
513 mov a6, a7
514.Lback13:
515#if XCHAL_UNALIGNED_LOAD_EXCEPTION || SIM_CHECKS_ALIGNMENT
516 add a3, a3, a11 # readjust a3 with correct misalignment
517#endif
518 bbsi.l a4, 1, .Lback14
519 bbsi.l a4, 0, .Lback15
520.Lbackdone:
521 abi_ret_default
522.Lback14:
523 # copy 2 bytes
524 addi a3, a3, -2
525 l8ui a6, a3, 0
526 l8ui a7, a3, 1
527 addi a5, a5, -2
528 s8i a6, a5, 0
529 s8i a7, a5, 1
530 bbsi.l a4, 0, .Lback15
531 abi_ret_default
532.Lback15:
533 # copy 1 byte
534 addi a3, a3, -1
535 addi a5, a5, -1
536 l8ui a6, a3, 0
537 s8i a6, a5, 0
538 abi_ret_default
539
540ENDPROC(__memmove)
541EXPORT_SYMBOL(__memmove)
542EXPORT_SYMBOL(memmove)