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author | 2025-03-08 22:04:20 +0800 | |
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committer | 2025-03-08 22:04:20 +0800 | |
commit | a07bb8fd1299070229f0e8f3dcb57ffd5ef9870a (patch) | |
tree | 84f21bd0bf7071bc5fc7dd989e77d7ceb5476682 /arch/mips/cavium-octeon/octeon-memcpy.S | |
download | ohosKernel-a07bb8fd1299070229f0e8f3dcb57ffd5ef9870a.tar.gz ohosKernel-a07bb8fd1299070229f0e8f3dcb57ffd5ef9870a.zip |
Initial commit: OpenHarmony-v4.0-ReleaseOpenHarmony-v4.0-Release
Diffstat (limited to 'arch/mips/cavium-octeon/octeon-memcpy.S')
-rw-r--r-- | arch/mips/cavium-octeon/octeon-memcpy.S | 482 |
1 files changed, 482 insertions, 0 deletions
diff --git a/arch/mips/cavium-octeon/octeon-memcpy.S b/arch/mips/cavium-octeon/octeon-memcpy.S new file mode 100644 index 000000000..0a7c9834b --- /dev/null +++ b/arch/mips/cavium-octeon/octeon-memcpy.S | |||
@@ -0,0 +1,482 @@ | |||
1 | /* | ||
2 | * This file is subject to the terms and conditions of the GNU General Public | ||
3 | * License. See the file "COPYING" in the main directory of this archive | ||
4 | * for more details. | ||
5 | * | ||
6 | * Unified implementation of memcpy, memmove and the __copy_user backend. | ||
7 | * | ||
8 | * Copyright (C) 1998, 99, 2000, 01, 2002 Ralf Baechle (ralf@gnu.org) | ||
9 | * Copyright (C) 1999, 2000, 01, 2002 Silicon Graphics, Inc. | ||
10 | * Copyright (C) 2002 Broadcom, Inc. | ||
11 | * memcpy/copy_user author: Mark Vandevoorde | ||
12 | * | ||
13 | * Mnemonic names for arguments to memcpy/__copy_user | ||
14 | */ | ||
15 | |||
16 | #include <asm/asm.h> | ||
17 | #include <asm/asm-offsets.h> | ||
18 | #include <asm/export.h> | ||
19 | #include <asm/regdef.h> | ||
20 | |||
21 | #define dst a0 | ||
22 | #define src a1 | ||
23 | #define len a2 | ||
24 | |||
25 | /* | ||
26 | * Spec | ||
27 | * | ||
28 | * memcpy copies len bytes from src to dst and sets v0 to dst. | ||
29 | * It assumes that | ||
30 | * - src and dst don't overlap | ||
31 | * - src is readable | ||
32 | * - dst is writable | ||
33 | * memcpy uses the standard calling convention | ||
34 | * | ||
35 | * __copy_user copies up to len bytes from src to dst and sets a2 (len) to | ||
36 | * the number of uncopied bytes due to an exception caused by a read or write. | ||
37 | * __copy_user assumes that src and dst don't overlap, and that the call is | ||
38 | * implementing one of the following: | ||
39 | * copy_to_user | ||
40 | * - src is readable (no exceptions when reading src) | ||
41 | * copy_from_user | ||
42 | * - dst is writable (no exceptions when writing dst) | ||
43 | * __copy_user uses a non-standard calling convention; see | ||
44 | * arch/mips/include/asm/uaccess.h | ||
45 | * | ||
46 | * When an exception happens on a load, the handler must | ||
47 | # ensure that all of the destination buffer is overwritten to prevent | ||
48 | * leaking information to user mode programs. | ||
49 | */ | ||
50 | |||
51 | /* | ||
52 | * Implementation | ||
53 | */ | ||
54 | |||
55 | /* | ||
56 | * The exception handler for loads requires that: | ||
57 | * 1- AT contain the address of the byte just past the end of the source | ||
58 | * of the copy, | ||
59 | * 2- src_entry <= src < AT, and | ||
60 | * 3- (dst - src) == (dst_entry - src_entry), | ||
61 | * The _entry suffix denotes values when __copy_user was called. | ||
62 | * | ||
63 | * (1) is set up up by uaccess.h and maintained by not writing AT in copy_user | ||
64 | * (2) is met by incrementing src by the number of bytes copied | ||
65 | * (3) is met by not doing loads between a pair of increments of dst and src | ||
66 | * | ||
67 | * The exception handlers for stores adjust len (if necessary) and return. | ||
68 | * These handlers do not need to overwrite any data. | ||
69 | * | ||
70 | * For __rmemcpy and memmove an exception is always a kernel bug, therefore | ||
71 | * they're not protected. | ||
72 | */ | ||
73 | |||
74 | #define EXC(inst_reg,addr,handler) \ | ||
75 | 9: inst_reg, addr; \ | ||
76 | .section __ex_table,"a"; \ | ||
77 | PTR 9b, handler; \ | ||
78 | .previous | ||
79 | |||
80 | /* | ||
81 | * Only on the 64-bit kernel we can made use of 64-bit registers. | ||
82 | */ | ||
83 | |||
84 | #define LOAD ld | ||
85 | #define LOADL ldl | ||
86 | #define LOADR ldr | ||
87 | #define STOREL sdl | ||
88 | #define STORER sdr | ||
89 | #define STORE sd | ||
90 | #define ADD daddu | ||
91 | #define SUB dsubu | ||
92 | #define SRL dsrl | ||
93 | #define SRA dsra | ||
94 | #define SLL dsll | ||
95 | #define SLLV dsllv | ||
96 | #define SRLV dsrlv | ||
97 | #define NBYTES 8 | ||
98 | #define LOG_NBYTES 3 | ||
99 | |||
100 | /* | ||
101 | * As we are sharing code base with the mips32 tree (which use the o32 ABI | ||
102 | * register definitions). We need to redefine the register definitions from | ||
103 | * the n64 ABI register naming to the o32 ABI register naming. | ||
104 | */ | ||
105 | #undef t0 | ||
106 | #undef t1 | ||
107 | #undef t2 | ||
108 | #undef t3 | ||
109 | #define t0 $8 | ||
110 | #define t1 $9 | ||
111 | #define t2 $10 | ||
112 | #define t3 $11 | ||
113 | #define t4 $12 | ||
114 | #define t5 $13 | ||
115 | #define t6 $14 | ||
116 | #define t7 $15 | ||
117 | |||
118 | #ifdef CONFIG_CPU_LITTLE_ENDIAN | ||
119 | #define LDFIRST LOADR | ||
120 | #define LDREST LOADL | ||
121 | #define STFIRST STORER | ||
122 | #define STREST STOREL | ||
123 | #define SHIFT_DISCARD SLLV | ||
124 | #else | ||
125 | #define LDFIRST LOADL | ||
126 | #define LDREST LOADR | ||
127 | #define STFIRST STOREL | ||
128 | #define STREST STORER | ||
129 | #define SHIFT_DISCARD SRLV | ||
130 | #endif | ||
131 | |||
132 | #define FIRST(unit) ((unit)*NBYTES) | ||
133 | #define REST(unit) (FIRST(unit)+NBYTES-1) | ||
134 | #define UNIT(unit) FIRST(unit) | ||
135 | |||
136 | #define ADDRMASK (NBYTES-1) | ||
137 | |||
138 | .text | ||
139 | .set noreorder | ||
140 | .set noat | ||
141 | |||
142 | /* | ||
143 | * A combined memcpy/__copy_user | ||
144 | * __copy_user sets len to 0 for success; else to an upper bound of | ||
145 | * the number of uncopied bytes. | ||
146 | * memcpy sets v0 to dst. | ||
147 | */ | ||
148 | .align 5 | ||
149 | LEAF(memcpy) /* a0=dst a1=src a2=len */ | ||
150 | EXPORT_SYMBOL(memcpy) | ||
151 | move v0, dst /* return value */ | ||
152 | __memcpy: | ||
153 | FEXPORT(__copy_user) | ||
154 | EXPORT_SYMBOL(__copy_user) | ||
155 | /* | ||
156 | * Note: dst & src may be unaligned, len may be 0 | ||
157 | * Temps | ||
158 | */ | ||
159 | # | ||
160 | # Octeon doesn't care if the destination is unaligned. The hardware | ||
161 | # can fix it faster than we can special case the assembly. | ||
162 | # | ||
163 | pref 0, 0(src) | ||
164 | sltu t0, len, NBYTES # Check if < 1 word | ||
165 | bnez t0, copy_bytes_checklen | ||
166 | and t0, src, ADDRMASK # Check if src unaligned | ||
167 | bnez t0, src_unaligned | ||
168 | sltu t0, len, 4*NBYTES # Check if < 4 words | ||
169 | bnez t0, less_than_4units | ||
170 | sltu t0, len, 8*NBYTES # Check if < 8 words | ||
171 | bnez t0, less_than_8units | ||
172 | sltu t0, len, 16*NBYTES # Check if < 16 words | ||
173 | bnez t0, cleanup_both_aligned | ||
174 | sltu t0, len, 128+1 # Check if len < 129 | ||
175 | bnez t0, 1f # Skip prefetch if len is too short | ||
176 | sltu t0, len, 256+1 # Check if len < 257 | ||
177 | bnez t0, 1f # Skip prefetch if len is too short | ||
178 | pref 0, 128(src) # We must not prefetch invalid addresses | ||
179 | # | ||
180 | # This is where we loop if there is more than 128 bytes left | ||
181 | 2: pref 0, 256(src) # We must not prefetch invalid addresses | ||
182 | # | ||
183 | # This is where we loop if we can't prefetch anymore | ||
184 | 1: | ||
185 | EXC( LOAD t0, UNIT(0)(src), l_exc) | ||
186 | EXC( LOAD t1, UNIT(1)(src), l_exc_copy) | ||
187 | EXC( LOAD t2, UNIT(2)(src), l_exc_copy) | ||
188 | EXC( LOAD t3, UNIT(3)(src), l_exc_copy) | ||
189 | SUB len, len, 16*NBYTES | ||
190 | EXC( STORE t0, UNIT(0)(dst), s_exc_p16u) | ||
191 | EXC( STORE t1, UNIT(1)(dst), s_exc_p15u) | ||
192 | EXC( STORE t2, UNIT(2)(dst), s_exc_p14u) | ||
193 | EXC( STORE t3, UNIT(3)(dst), s_exc_p13u) | ||
194 | EXC( LOAD t0, UNIT(4)(src), l_exc_copy) | ||
195 | EXC( LOAD t1, UNIT(5)(src), l_exc_copy) | ||
196 | EXC( LOAD t2, UNIT(6)(src), l_exc_copy) | ||
197 | EXC( LOAD t3, UNIT(7)(src), l_exc_copy) | ||
198 | EXC( STORE t0, UNIT(4)(dst), s_exc_p12u) | ||
199 | EXC( STORE t1, UNIT(5)(dst), s_exc_p11u) | ||
200 | EXC( STORE t2, UNIT(6)(dst), s_exc_p10u) | ||
201 | ADD src, src, 16*NBYTES | ||
202 | EXC( STORE t3, UNIT(7)(dst), s_exc_p9u) | ||
203 | ADD dst, dst, 16*NBYTES | ||
204 | EXC( LOAD t0, UNIT(-8)(src), l_exc_copy_rewind16) | ||
205 | EXC( LOAD t1, UNIT(-7)(src), l_exc_copy_rewind16) | ||
206 | EXC( LOAD t2, UNIT(-6)(src), l_exc_copy_rewind16) | ||
207 | EXC( LOAD t3, UNIT(-5)(src), l_exc_copy_rewind16) | ||
208 | EXC( STORE t0, UNIT(-8)(dst), s_exc_p8u) | ||
209 | EXC( STORE t1, UNIT(-7)(dst), s_exc_p7u) | ||
210 | EXC( STORE t2, UNIT(-6)(dst), s_exc_p6u) | ||
211 | EXC( STORE t3, UNIT(-5)(dst), s_exc_p5u) | ||
212 | EXC( LOAD t0, UNIT(-4)(src), l_exc_copy_rewind16) | ||
213 | EXC( LOAD t1, UNIT(-3)(src), l_exc_copy_rewind16) | ||
214 | EXC( LOAD t2, UNIT(-2)(src), l_exc_copy_rewind16) | ||
215 | EXC( LOAD t3, UNIT(-1)(src), l_exc_copy_rewind16) | ||
216 | EXC( STORE t0, UNIT(-4)(dst), s_exc_p4u) | ||
217 | EXC( STORE t1, UNIT(-3)(dst), s_exc_p3u) | ||
218 | EXC( STORE t2, UNIT(-2)(dst), s_exc_p2u) | ||
219 | EXC( STORE t3, UNIT(-1)(dst), s_exc_p1u) | ||
220 | sltu t0, len, 256+1 # See if we can prefetch more | ||
221 | beqz t0, 2b | ||
222 | sltu t0, len, 128 # See if we can loop more time | ||
223 | beqz t0, 1b | ||
224 | nop | ||
225 | # | ||
226 | # Jump here if there are less than 16*NBYTES left. | ||
227 | # | ||
228 | cleanup_both_aligned: | ||
229 | beqz len, done | ||
230 | sltu t0, len, 8*NBYTES | ||
231 | bnez t0, less_than_8units | ||
232 | nop | ||
233 | EXC( LOAD t0, UNIT(0)(src), l_exc) | ||
234 | EXC( LOAD t1, UNIT(1)(src), l_exc_copy) | ||
235 | EXC( LOAD t2, UNIT(2)(src), l_exc_copy) | ||
236 | EXC( LOAD t3, UNIT(3)(src), l_exc_copy) | ||
237 | SUB len, len, 8*NBYTES | ||
238 | EXC( STORE t0, UNIT(0)(dst), s_exc_p8u) | ||
239 | EXC( STORE t1, UNIT(1)(dst), s_exc_p7u) | ||
240 | EXC( STORE t2, UNIT(2)(dst), s_exc_p6u) | ||
241 | EXC( STORE t3, UNIT(3)(dst), s_exc_p5u) | ||
242 | EXC( LOAD t0, UNIT(4)(src), l_exc_copy) | ||
243 | EXC( LOAD t1, UNIT(5)(src), l_exc_copy) | ||
244 | EXC( LOAD t2, UNIT(6)(src), l_exc_copy) | ||
245 | EXC( LOAD t3, UNIT(7)(src), l_exc_copy) | ||
246 | EXC( STORE t0, UNIT(4)(dst), s_exc_p4u) | ||
247 | EXC( STORE t1, UNIT(5)(dst), s_exc_p3u) | ||
248 | EXC( STORE t2, UNIT(6)(dst), s_exc_p2u) | ||
249 | EXC( STORE t3, UNIT(7)(dst), s_exc_p1u) | ||
250 | ADD src, src, 8*NBYTES | ||
251 | beqz len, done | ||
252 | ADD dst, dst, 8*NBYTES | ||
253 | # | ||
254 | # Jump here if there are less than 8*NBYTES left. | ||
255 | # | ||
256 | less_than_8units: | ||
257 | sltu t0, len, 4*NBYTES | ||
258 | bnez t0, less_than_4units | ||
259 | nop | ||
260 | EXC( LOAD t0, UNIT(0)(src), l_exc) | ||
261 | EXC( LOAD t1, UNIT(1)(src), l_exc_copy) | ||
262 | EXC( LOAD t2, UNIT(2)(src), l_exc_copy) | ||
263 | EXC( LOAD t3, UNIT(3)(src), l_exc_copy) | ||
264 | SUB len, len, 4*NBYTES | ||
265 | EXC( STORE t0, UNIT(0)(dst), s_exc_p4u) | ||
266 | EXC( STORE t1, UNIT(1)(dst), s_exc_p3u) | ||
267 | EXC( STORE t2, UNIT(2)(dst), s_exc_p2u) | ||
268 | EXC( STORE t3, UNIT(3)(dst), s_exc_p1u) | ||
269 | ADD src, src, 4*NBYTES | ||
270 | beqz len, done | ||
271 | ADD dst, dst, 4*NBYTES | ||
272 | # | ||
273 | # Jump here if there are less than 4*NBYTES left. This means | ||
274 | # we may need to copy up to 3 NBYTES words. | ||
275 | # | ||
276 | less_than_4units: | ||
277 | sltu t0, len, 1*NBYTES | ||
278 | bnez t0, copy_bytes_checklen | ||
279 | nop | ||
280 | # | ||
281 | # 1) Copy NBYTES, then check length again | ||
282 | # | ||
283 | EXC( LOAD t0, 0(src), l_exc) | ||
284 | SUB len, len, NBYTES | ||
285 | sltu t1, len, 8 | ||
286 | EXC( STORE t0, 0(dst), s_exc_p1u) | ||
287 | ADD src, src, NBYTES | ||
288 | bnez t1, copy_bytes_checklen | ||
289 | ADD dst, dst, NBYTES | ||
290 | # | ||
291 | # 2) Copy NBYTES, then check length again | ||
292 | # | ||
293 | EXC( LOAD t0, 0(src), l_exc) | ||
294 | SUB len, len, NBYTES | ||
295 | sltu t1, len, 8 | ||
296 | EXC( STORE t0, 0(dst), s_exc_p1u) | ||
297 | ADD src, src, NBYTES | ||
298 | bnez t1, copy_bytes_checklen | ||
299 | ADD dst, dst, NBYTES | ||
300 | # | ||
301 | # 3) Copy NBYTES, then check length again | ||
302 | # | ||
303 | EXC( LOAD t0, 0(src), l_exc) | ||
304 | SUB len, len, NBYTES | ||
305 | ADD src, src, NBYTES | ||
306 | ADD dst, dst, NBYTES | ||
307 | b copy_bytes_checklen | ||
308 | EXC( STORE t0, -8(dst), s_exc_p1u) | ||
309 | |||
310 | src_unaligned: | ||
311 | #define rem t8 | ||
312 | SRL t0, len, LOG_NBYTES+2 # +2 for 4 units/iter | ||
313 | beqz t0, cleanup_src_unaligned | ||
314 | and rem, len, (4*NBYTES-1) # rem = len % 4*NBYTES | ||
315 | 1: | ||
316 | /* | ||
317 | * Avoid consecutive LD*'s to the same register since some mips | ||
318 | * implementations can't issue them in the same cycle. | ||
319 | * It's OK to load FIRST(N+1) before REST(N) because the two addresses | ||
320 | * are to the same unit (unless src is aligned, but it's not). | ||
321 | */ | ||
322 | EXC( LDFIRST t0, FIRST(0)(src), l_exc) | ||
323 | EXC( LDFIRST t1, FIRST(1)(src), l_exc_copy) | ||
324 | SUB len, len, 4*NBYTES | ||
325 | EXC( LDREST t0, REST(0)(src), l_exc_copy) | ||
326 | EXC( LDREST t1, REST(1)(src), l_exc_copy) | ||
327 | EXC( LDFIRST t2, FIRST(2)(src), l_exc_copy) | ||
328 | EXC( LDFIRST t3, FIRST(3)(src), l_exc_copy) | ||
329 | EXC( LDREST t2, REST(2)(src), l_exc_copy) | ||
330 | EXC( LDREST t3, REST(3)(src), l_exc_copy) | ||
331 | ADD src, src, 4*NBYTES | ||
332 | EXC( STORE t0, UNIT(0)(dst), s_exc_p4u) | ||
333 | EXC( STORE t1, UNIT(1)(dst), s_exc_p3u) | ||
334 | EXC( STORE t2, UNIT(2)(dst), s_exc_p2u) | ||
335 | EXC( STORE t3, UNIT(3)(dst), s_exc_p1u) | ||
336 | bne len, rem, 1b | ||
337 | ADD dst, dst, 4*NBYTES | ||
338 | |||
339 | cleanup_src_unaligned: | ||
340 | beqz len, done | ||
341 | and rem, len, NBYTES-1 # rem = len % NBYTES | ||
342 | beq rem, len, copy_bytes | ||
343 | nop | ||
344 | 1: | ||
345 | EXC( LDFIRST t0, FIRST(0)(src), l_exc) | ||
346 | EXC( LDREST t0, REST(0)(src), l_exc_copy) | ||
347 | SUB len, len, NBYTES | ||
348 | EXC( STORE t0, 0(dst), s_exc_p1u) | ||
349 | ADD src, src, NBYTES | ||
350 | bne len, rem, 1b | ||
351 | ADD dst, dst, NBYTES | ||
352 | |||
353 | copy_bytes_checklen: | ||
354 | beqz len, done | ||
355 | nop | ||
356 | copy_bytes: | ||
357 | /* 0 < len < NBYTES */ | ||
358 | #define COPY_BYTE(N) \ | ||
359 | EXC( lb t0, N(src), l_exc); \ | ||
360 | SUB len, len, 1; \ | ||
361 | beqz len, done; \ | ||
362 | EXC( sb t0, N(dst), s_exc_p1) | ||
363 | |||
364 | COPY_BYTE(0) | ||
365 | COPY_BYTE(1) | ||
366 | COPY_BYTE(2) | ||
367 | COPY_BYTE(3) | ||
368 | COPY_BYTE(4) | ||
369 | COPY_BYTE(5) | ||
370 | EXC( lb t0, NBYTES-2(src), l_exc) | ||
371 | SUB len, len, 1 | ||
372 | jr ra | ||
373 | EXC( sb t0, NBYTES-2(dst), s_exc_p1) | ||
374 | done: | ||
375 | jr ra | ||
376 | nop | ||
377 | END(memcpy) | ||
378 | |||
379 | l_exc_copy_rewind16: | ||
380 | /* Rewind src and dst by 16*NBYTES for l_exc_copy */ | ||
381 | SUB src, src, 16*NBYTES | ||
382 | SUB dst, dst, 16*NBYTES | ||
383 | l_exc_copy: | ||
384 | /* | ||
385 | * Copy bytes from src until faulting load address (or until a | ||
386 | * lb faults) | ||
387 | * | ||
388 | * When reached by a faulting LDFIRST/LDREST, THREAD_BUADDR($28) | ||
389 | * may be more than a byte beyond the last address. | ||
390 | * Hence, the lb below may get an exception. | ||
391 | * | ||
392 | * Assumes src < THREAD_BUADDR($28) | ||
393 | */ | ||
394 | LOAD t0, TI_TASK($28) | ||
395 | LOAD t0, THREAD_BUADDR(t0) | ||
396 | 1: | ||
397 | EXC( lb t1, 0(src), l_exc) | ||
398 | ADD src, src, 1 | ||
399 | sb t1, 0(dst) # can't fault -- we're copy_from_user | ||
400 | bne src, t0, 1b | ||
401 | ADD dst, dst, 1 | ||
402 | l_exc: | ||
403 | LOAD t0, TI_TASK($28) | ||
404 | LOAD t0, THREAD_BUADDR(t0) # t0 is just past last good address | ||
405 | SUB len, AT, t0 # len number of uncopied bytes | ||
406 | jr ra | ||
407 | nop | ||
408 | |||
409 | |||
410 | #define SEXC(n) \ | ||
411 | s_exc_p ## n ## u: \ | ||
412 | jr ra; \ | ||
413 | ADD len, len, n*NBYTES | ||
414 | |||
415 | SEXC(16) | ||
416 | SEXC(15) | ||
417 | SEXC(14) | ||
418 | SEXC(13) | ||
419 | SEXC(12) | ||
420 | SEXC(11) | ||
421 | SEXC(10) | ||
422 | SEXC(9) | ||
423 | SEXC(8) | ||
424 | SEXC(7) | ||
425 | SEXC(6) | ||
426 | SEXC(5) | ||
427 | SEXC(4) | ||
428 | SEXC(3) | ||
429 | SEXC(2) | ||
430 | SEXC(1) | ||
431 | |||
432 | s_exc_p1: | ||
433 | jr ra | ||
434 | ADD len, len, 1 | ||
435 | s_exc: | ||
436 | jr ra | ||
437 | nop | ||
438 | |||
439 | .align 5 | ||
440 | LEAF(memmove) | ||
441 | EXPORT_SYMBOL(memmove) | ||
442 | ADD t0, a0, a2 | ||
443 | ADD t1, a1, a2 | ||
444 | sltu t0, a1, t0 # dst + len <= src -> memcpy | ||
445 | sltu t1, a0, t1 # dst >= src + len -> memcpy | ||
446 | and t0, t1 | ||
447 | beqz t0, __memcpy | ||
448 | move v0, a0 /* return value */ | ||
449 | beqz a2, r_out | ||
450 | END(memmove) | ||
451 | |||
452 | /* fall through to __rmemcpy */ | ||
453 | LEAF(__rmemcpy) /* a0=dst a1=src a2=len */ | ||
454 | sltu t0, a1, a0 | ||
455 | beqz t0, r_end_bytes_up # src >= dst | ||
456 | nop | ||
457 | ADD a0, a2 # dst = dst + len | ||
458 | ADD a1, a2 # src = src + len | ||
459 | |||
460 | r_end_bytes: | ||
461 | lb t0, -1(a1) | ||
462 | SUB a2, a2, 0x1 | ||
463 | sb t0, -1(a0) | ||
464 | SUB a1, a1, 0x1 | ||
465 | bnez a2, r_end_bytes | ||
466 | SUB a0, a0, 0x1 | ||
467 | |||
468 | r_out: | ||
469 | jr ra | ||
470 | move a2, zero | ||
471 | |||
472 | r_end_bytes_up: | ||
473 | lb t0, (a1) | ||
474 | SUB a2, a2, 0x1 | ||
475 | sb t0, (a0) | ||
476 | ADD a1, a1, 0x1 | ||
477 | bnez a2, r_end_bytes_up | ||
478 | ADD a0, a0, 0x1 | ||
479 | |||
480 | jr ra | ||
481 | move a2, zero | ||
482 | END(__rmemcpy) | ||