ARM: fix build error in arch/arm/kernel/process.c
[linux-3.10.git] / arch / arm / lib / uaccess.S
1 /*
2  *  linux/arch/arm/lib/uaccess.S
3  *
4  *  Copyright (C) 1995, 1996,1997,1998 Russell King
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  *
10  *  Routines to block copy data to/from user memory
11  *   These are highly optimised both for the 4k page size
12  *   and for various alignments.
13  */
14 #include <linux/linkage.h>
15 #include <asm/assembler.h>
16 #include <asm/errno.h>
17
18                 .text
19
20 #define PAGE_SHIFT 12
21
22 /* Prototype: int __copy_to_user(void *to, const char *from, size_t n)
23  * Purpose  : copy a block to user memory from kernel memory
24  * Params   : to   - user memory
25  *          : from - kernel memory
26  *          : n    - number of bytes to copy
27  * Returns  : Number of bytes NOT copied.
28  */
29
30 .Lc2u_dest_not_aligned:
31                 rsb     ip, ip, #4
32                 cmp     ip, #2
33                 ldrb    r3, [r1], #1
34 USER(           strbt   r3, [r0], #1)                   @ May fault
35                 ldrgeb  r3, [r1], #1
36 USER(           strgebt r3, [r0], #1)                   @ May fault
37                 ldrgtb  r3, [r1], #1
38 USER(           strgtbt r3, [r0], #1)                   @ May fault
39                 sub     r2, r2, ip
40                 b       .Lc2u_dest_aligned
41
42 ENTRY(__copy_to_user)
43                 stmfd   sp!, {r2, r4 - r7, lr}
44                 cmp     r2, #4
45                 blt     .Lc2u_not_enough
46                 ands    ip, r0, #3
47                 bne     .Lc2u_dest_not_aligned
48 .Lc2u_dest_aligned:
49
50                 ands    ip, r1, #3
51                 bne     .Lc2u_src_not_aligned
52 /*
53  * Seeing as there has to be at least 8 bytes to copy, we can
54  * copy one word, and force a user-mode page fault...
55  */
56
57 .Lc2u_0fupi:    subs    r2, r2, #4
58                 addmi   ip, r2, #4
59                 bmi     .Lc2u_0nowords
60                 ldr     r3, [r1], #4
61 USER(           strt    r3, [r0], #4)                   @ May fault
62                 mov     ip, r0, lsl #32 - PAGE_SHIFT    @ On each page, use a ld/st??t instruction
63                 rsb     ip, ip, #0
64                 movs    ip, ip, lsr #32 - PAGE_SHIFT
65                 beq     .Lc2u_0fupi
66 /*
67  * ip = max no. of bytes to copy before needing another "strt" insn
68  */
69                 cmp     r2, ip
70                 movlt   ip, r2
71                 sub     r2, r2, ip
72                 subs    ip, ip, #32
73                 blt     .Lc2u_0rem8lp
74
75 .Lc2u_0cpy8lp:  ldmia   r1!, {r3 - r6}
76                 stmia   r0!, {r3 - r6}                  @ Shouldnt fault
77                 ldmia   r1!, {r3 - r6}
78                 subs    ip, ip, #32
79                 stmia   r0!, {r3 - r6}                  @ Shouldnt fault
80                 bpl     .Lc2u_0cpy8lp
81
82 .Lc2u_0rem8lp:  cmn     ip, #16
83                 ldmgeia r1!, {r3 - r6}
84                 stmgeia r0!, {r3 - r6}                  @ Shouldnt fault
85                 tst     ip, #8
86                 ldmneia r1!, {r3 - r4}
87                 stmneia r0!, {r3 - r4}                  @ Shouldnt fault
88                 tst     ip, #4
89                 ldrne   r3, [r1], #4
90                 strnet  r3, [r0], #4                    @ Shouldnt fault
91                 ands    ip, ip, #3
92                 beq     .Lc2u_0fupi
93 .Lc2u_0nowords: teq     ip, #0
94                 beq     .Lc2u_finished
95 .Lc2u_nowords:  cmp     ip, #2
96                 ldrb    r3, [r1], #1
97 USER(           strbt   r3, [r0], #1)                   @ May fault
98                 ldrgeb  r3, [r1], #1
99 USER(           strgebt r3, [r0], #1)                   @ May fault
100                 ldrgtb  r3, [r1], #1
101 USER(           strgtbt r3, [r0], #1)                   @ May fault
102                 b       .Lc2u_finished
103
104 .Lc2u_not_enough:
105                 movs    ip, r2
106                 bne     .Lc2u_nowords
107 .Lc2u_finished: mov     r0, #0
108                 ldmfd   sp!, {r2, r4 - r7, pc}
109
110 .Lc2u_src_not_aligned:
111                 bic     r1, r1, #3
112                 ldr     r7, [r1], #4
113                 cmp     ip, #2
114                 bgt     .Lc2u_3fupi
115                 beq     .Lc2u_2fupi
116 .Lc2u_1fupi:    subs    r2, r2, #4
117                 addmi   ip, r2, #4
118                 bmi     .Lc2u_1nowords
119                 mov     r3, r7, pull #8
120                 ldr     r7, [r1], #4
121                 orr     r3, r3, r7, push #24
122 USER(           strt    r3, [r0], #4)                   @ May fault
123                 mov     ip, r0, lsl #32 - PAGE_SHIFT
124                 rsb     ip, ip, #0
125                 movs    ip, ip, lsr #32 - PAGE_SHIFT
126                 beq     .Lc2u_1fupi
127                 cmp     r2, ip
128                 movlt   ip, r2
129                 sub     r2, r2, ip
130                 subs    ip, ip, #16
131                 blt     .Lc2u_1rem8lp
132
133 .Lc2u_1cpy8lp:  mov     r3, r7, pull #8
134                 ldmia   r1!, {r4 - r7}
135                 subs    ip, ip, #16
136                 orr     r3, r3, r4, push #24
137                 mov     r4, r4, pull #8
138                 orr     r4, r4, r5, push #24
139                 mov     r5, r5, pull #8
140                 orr     r5, r5, r6, push #24
141                 mov     r6, r6, pull #8
142                 orr     r6, r6, r7, push #24
143                 stmia   r0!, {r3 - r6}                  @ Shouldnt fault
144                 bpl     .Lc2u_1cpy8lp
145
146 .Lc2u_1rem8lp:  tst     ip, #8
147                 movne   r3, r7, pull #8
148                 ldmneia r1!, {r4, r7}
149                 orrne   r3, r3, r4, push #24
150                 movne   r4, r4, pull #8
151                 orrne   r4, r4, r7, push #24
152                 stmneia r0!, {r3 - r4}                  @ Shouldnt fault
153                 tst     ip, #4
154                 movne   r3, r7, pull #8
155                 ldrne   r7, [r1], #4
156                 orrne   r3, r3, r7, push #24
157                 strnet  r3, [r0], #4                    @ Shouldnt fault
158                 ands    ip, ip, #3
159                 beq     .Lc2u_1fupi
160 .Lc2u_1nowords: mov     r3, r7, get_byte_1
161                 teq     ip, #0
162                 beq     .Lc2u_finished
163                 cmp     ip, #2
164 USER(           strbt   r3, [r0], #1)                   @ May fault
165                 movge   r3, r7, get_byte_2
166 USER(           strgebt r3, [r0], #1)                   @ May fault
167                 movgt   r3, r7, get_byte_3
168 USER(           strgtbt r3, [r0], #1)                   @ May fault
169                 b       .Lc2u_finished
170
171 .Lc2u_2fupi:    subs    r2, r2, #4
172                 addmi   ip, r2, #4
173                 bmi     .Lc2u_2nowords
174                 mov     r3, r7, pull #16
175                 ldr     r7, [r1], #4
176                 orr     r3, r3, r7, push #16
177 USER(           strt    r3, [r0], #4)                   @ May fault
178                 mov     ip, r0, lsl #32 - PAGE_SHIFT
179                 rsb     ip, ip, #0
180                 movs    ip, ip, lsr #32 - PAGE_SHIFT
181                 beq     .Lc2u_2fupi
182                 cmp     r2, ip
183                 movlt   ip, r2
184                 sub     r2, r2, ip
185                 subs    ip, ip, #16
186                 blt     .Lc2u_2rem8lp
187
188 .Lc2u_2cpy8lp:  mov     r3, r7, pull #16
189                 ldmia   r1!, {r4 - r7}
190                 subs    ip, ip, #16
191                 orr     r3, r3, r4, push #16
192                 mov     r4, r4, pull #16
193                 orr     r4, r4, r5, push #16
194                 mov     r5, r5, pull #16
195                 orr     r5, r5, r6, push #16
196                 mov     r6, r6, pull #16
197                 orr     r6, r6, r7, push #16
198                 stmia   r0!, {r3 - r6}                  @ Shouldnt fault
199                 bpl     .Lc2u_2cpy8lp
200
201 .Lc2u_2rem8lp:  tst     ip, #8
202                 movne   r3, r7, pull #16
203                 ldmneia r1!, {r4, r7}
204                 orrne   r3, r3, r4, push #16
205                 movne   r4, r4, pull #16
206                 orrne   r4, r4, r7, push #16
207                 stmneia r0!, {r3 - r4}                  @ Shouldnt fault
208                 tst     ip, #4
209                 movne   r3, r7, pull #16
210                 ldrne   r7, [r1], #4
211                 orrne   r3, r3, r7, push #16
212                 strnet  r3, [r0], #4                    @ Shouldnt fault
213                 ands    ip, ip, #3
214                 beq     .Lc2u_2fupi
215 .Lc2u_2nowords: mov     r3, r7, get_byte_2
216                 teq     ip, #0
217                 beq     .Lc2u_finished
218                 cmp     ip, #2
219 USER(           strbt   r3, [r0], #1)                   @ May fault
220                 movge   r3, r7, get_byte_3
221 USER(           strgebt r3, [r0], #1)                   @ May fault
222                 ldrgtb  r3, [r1], #0
223 USER(           strgtbt r3, [r0], #1)                   @ May fault
224                 b       .Lc2u_finished
225
226 .Lc2u_3fupi:    subs    r2, r2, #4
227                 addmi   ip, r2, #4
228                 bmi     .Lc2u_3nowords
229                 mov     r3, r7, pull #24
230                 ldr     r7, [r1], #4
231                 orr     r3, r3, r7, push #8
232 USER(           strt    r3, [r0], #4)                   @ May fault
233                 mov     ip, r0, lsl #32 - PAGE_SHIFT
234                 rsb     ip, ip, #0
235                 movs    ip, ip, lsr #32 - PAGE_SHIFT
236                 beq     .Lc2u_3fupi
237                 cmp     r2, ip
238                 movlt   ip, r2
239                 sub     r2, r2, ip
240                 subs    ip, ip, #16
241                 blt     .Lc2u_3rem8lp
242
243 .Lc2u_3cpy8lp:  mov     r3, r7, pull #24
244                 ldmia   r1!, {r4 - r7}
245                 subs    ip, ip, #16
246                 orr     r3, r3, r4, push #8
247                 mov     r4, r4, pull #24
248                 orr     r4, r4, r5, push #8
249                 mov     r5, r5, pull #24
250                 orr     r5, r5, r6, push #8
251                 mov     r6, r6, pull #24
252                 orr     r6, r6, r7, push #8
253                 stmia   r0!, {r3 - r6}                  @ Shouldnt fault
254                 bpl     .Lc2u_3cpy8lp
255
256 .Lc2u_3rem8lp:  tst     ip, #8
257                 movne   r3, r7, pull #24
258                 ldmneia r1!, {r4, r7}
259                 orrne   r3, r3, r4, push #8
260                 movne   r4, r4, pull #24
261                 orrne   r4, r4, r7, push #8
262                 stmneia r0!, {r3 - r4}                  @ Shouldnt fault
263                 tst     ip, #4
264                 movne   r3, r7, pull #24
265                 ldrne   r7, [r1], #4
266                 orrne   r3, r3, r7, push #8
267                 strnet  r3, [r0], #4                    @ Shouldnt fault
268                 ands    ip, ip, #3
269                 beq     .Lc2u_3fupi
270 .Lc2u_3nowords: mov     r3, r7, get_byte_3
271                 teq     ip, #0
272                 beq     .Lc2u_finished
273                 cmp     ip, #2
274 USER(           strbt   r3, [r0], #1)                   @ May fault
275                 ldrgeb  r3, [r1], #1
276 USER(           strgebt r3, [r0], #1)                   @ May fault
277                 ldrgtb  r3, [r1], #0
278 USER(           strgtbt r3, [r0], #1)                   @ May fault
279                 b       .Lc2u_finished
280 ENDPROC(__copy_to_user)
281
282                 .pushsection .fixup,"ax"
283                 .align  0
284 9001:           ldmfd   sp!, {r0, r4 - r7, pc}
285                 .popsection
286
287 /* Prototype: unsigned long __copy_from_user(void *to,const void *from,unsigned long n);
288  * Purpose  : copy a block from user memory to kernel memory
289  * Params   : to   - kernel memory
290  *          : from - user memory
291  *          : n    - number of bytes to copy
292  * Returns  : Number of bytes NOT copied.
293  */
294 .Lcfu_dest_not_aligned:
295                 rsb     ip, ip, #4
296                 cmp     ip, #2
297 USER(           ldrbt   r3, [r1], #1)                   @ May fault
298                 strb    r3, [r0], #1
299 USER(           ldrgebt r3, [r1], #1)                   @ May fault
300                 strgeb  r3, [r0], #1
301 USER(           ldrgtbt r3, [r1], #1)                   @ May fault
302                 strgtb  r3, [r0], #1
303                 sub     r2, r2, ip
304                 b       .Lcfu_dest_aligned
305
306 ENTRY(__copy_from_user)
307                 stmfd   sp!, {r0, r2, r4 - r7, lr}
308                 cmp     r2, #4
309                 blt     .Lcfu_not_enough
310                 ands    ip, r0, #3
311                 bne     .Lcfu_dest_not_aligned
312 .Lcfu_dest_aligned:
313                 ands    ip, r1, #3
314                 bne     .Lcfu_src_not_aligned
315
316 /*
317  * Seeing as there has to be at least 8 bytes to copy, we can
318  * copy one word, and force a user-mode page fault...
319  */
320
321 .Lcfu_0fupi:    subs    r2, r2, #4
322                 addmi   ip, r2, #4
323                 bmi     .Lcfu_0nowords
324 USER(           ldrt    r3, [r1], #4)
325                 str     r3, [r0], #4
326                 mov     ip, r1, lsl #32 - PAGE_SHIFT    @ On each page, use a ld/st??t instruction
327                 rsb     ip, ip, #0
328                 movs    ip, ip, lsr #32 - PAGE_SHIFT
329                 beq     .Lcfu_0fupi
330 /*
331  * ip = max no. of bytes to copy before needing another "strt" insn
332  */
333                 cmp     r2, ip
334                 movlt   ip, r2
335                 sub     r2, r2, ip
336                 subs    ip, ip, #32
337                 blt     .Lcfu_0rem8lp
338
339 .Lcfu_0cpy8lp:  ldmia   r1!, {r3 - r6}                  @ Shouldnt fault
340                 stmia   r0!, {r3 - r6}
341                 ldmia   r1!, {r3 - r6}                  @ Shouldnt fault
342                 subs    ip, ip, #32
343                 stmia   r0!, {r3 - r6}
344                 bpl     .Lcfu_0cpy8lp
345
346 .Lcfu_0rem8lp:  cmn     ip, #16
347                 ldmgeia r1!, {r3 - r6}                  @ Shouldnt fault
348                 stmgeia r0!, {r3 - r6}
349                 tst     ip, #8
350                 ldmneia r1!, {r3 - r4}                  @ Shouldnt fault
351                 stmneia r0!, {r3 - r4}
352                 tst     ip, #4
353                 ldrnet  r3, [r1], #4                    @ Shouldnt fault
354                 strne   r3, [r0], #4
355                 ands    ip, ip, #3
356                 beq     .Lcfu_0fupi
357 .Lcfu_0nowords: teq     ip, #0
358                 beq     .Lcfu_finished
359 .Lcfu_nowords:  cmp     ip, #2
360 USER(           ldrbt   r3, [r1], #1)                   @ May fault
361                 strb    r3, [r0], #1
362 USER(           ldrgebt r3, [r1], #1)                   @ May fault
363                 strgeb  r3, [r0], #1
364 USER(           ldrgtbt r3, [r1], #1)                   @ May fault
365                 strgtb  r3, [r0], #1
366                 b       .Lcfu_finished
367
368 .Lcfu_not_enough:
369                 movs    ip, r2
370                 bne     .Lcfu_nowords
371 .Lcfu_finished: mov     r0, #0
372                 add     sp, sp, #8
373                 ldmfd   sp!, {r4 - r7, pc}
374
375 .Lcfu_src_not_aligned:
376                 bic     r1, r1, #3
377 USER(           ldrt    r7, [r1], #4)                   @ May fault
378                 cmp     ip, #2
379                 bgt     .Lcfu_3fupi
380                 beq     .Lcfu_2fupi
381 .Lcfu_1fupi:    subs    r2, r2, #4
382                 addmi   ip, r2, #4
383                 bmi     .Lcfu_1nowords
384                 mov     r3, r7, pull #8
385 USER(           ldrt    r7, [r1], #4)                   @ May fault
386                 orr     r3, r3, r7, push #24
387                 str     r3, [r0], #4
388                 mov     ip, r1, lsl #32 - PAGE_SHIFT
389                 rsb     ip, ip, #0
390                 movs    ip, ip, lsr #32 - PAGE_SHIFT
391                 beq     .Lcfu_1fupi
392                 cmp     r2, ip
393                 movlt   ip, r2
394                 sub     r2, r2, ip
395                 subs    ip, ip, #16
396                 blt     .Lcfu_1rem8lp
397
398 .Lcfu_1cpy8lp:  mov     r3, r7, pull #8
399                 ldmia   r1!, {r4 - r7}                  @ Shouldnt fault
400                 subs    ip, ip, #16
401                 orr     r3, r3, r4, push #24
402                 mov     r4, r4, pull #8
403                 orr     r4, r4, r5, push #24
404                 mov     r5, r5, pull #8
405                 orr     r5, r5, r6, push #24
406                 mov     r6, r6, pull #8
407                 orr     r6, r6, r7, push #24
408                 stmia   r0!, {r3 - r6}
409                 bpl     .Lcfu_1cpy8lp
410
411 .Lcfu_1rem8lp:  tst     ip, #8
412                 movne   r3, r7, pull #8
413                 ldmneia r1!, {r4, r7}                   @ Shouldnt fault
414                 orrne   r3, r3, r4, push #24
415                 movne   r4, r4, pull #8
416                 orrne   r4, r4, r7, push #24
417                 stmneia r0!, {r3 - r4}
418                 tst     ip, #4
419                 movne   r3, r7, pull #8
420 USER(           ldrnet  r7, [r1], #4)                   @ May fault
421                 orrne   r3, r3, r7, push #24
422                 strne   r3, [r0], #4
423                 ands    ip, ip, #3
424                 beq     .Lcfu_1fupi
425 .Lcfu_1nowords: mov     r3, r7, get_byte_1
426                 teq     ip, #0
427                 beq     .Lcfu_finished
428                 cmp     ip, #2
429                 strb    r3, [r0], #1
430                 movge   r3, r7, get_byte_2
431                 strgeb  r3, [r0], #1
432                 movgt   r3, r7, get_byte_3
433                 strgtb  r3, [r0], #1
434                 b       .Lcfu_finished
435
436 .Lcfu_2fupi:    subs    r2, r2, #4
437                 addmi   ip, r2, #4
438                 bmi     .Lcfu_2nowords
439                 mov     r3, r7, pull #16
440 USER(           ldrt    r7, [r1], #4)                   @ May fault
441                 orr     r3, r3, r7, push #16
442                 str     r3, [r0], #4
443                 mov     ip, r1, lsl #32 - PAGE_SHIFT
444                 rsb     ip, ip, #0
445                 movs    ip, ip, lsr #32 - PAGE_SHIFT
446                 beq     .Lcfu_2fupi
447                 cmp     r2, ip
448                 movlt   ip, r2
449                 sub     r2, r2, ip
450                 subs    ip, ip, #16
451                 blt     .Lcfu_2rem8lp
452
453
454 .Lcfu_2cpy8lp:  mov     r3, r7, pull #16
455                 ldmia   r1!, {r4 - r7}                  @ Shouldnt fault
456                 subs    ip, ip, #16
457                 orr     r3, r3, r4, push #16
458                 mov     r4, r4, pull #16
459                 orr     r4, r4, r5, push #16
460                 mov     r5, r5, pull #16
461                 orr     r5, r5, r6, push #16
462                 mov     r6, r6, pull #16
463                 orr     r6, r6, r7, push #16
464                 stmia   r0!, {r3 - r6}
465                 bpl     .Lcfu_2cpy8lp
466
467 .Lcfu_2rem8lp:  tst     ip, #8
468                 movne   r3, r7, pull #16
469                 ldmneia r1!, {r4, r7}                   @ Shouldnt fault
470                 orrne   r3, r3, r4, push #16
471                 movne   r4, r4, pull #16
472                 orrne   r4, r4, r7, push #16
473                 stmneia r0!, {r3 - r4}
474                 tst     ip, #4
475                 movne   r3, r7, pull #16
476 USER(           ldrnet  r7, [r1], #4)                   @ May fault
477                 orrne   r3, r3, r7, push #16
478                 strne   r3, [r0], #4
479                 ands    ip, ip, #3
480                 beq     .Lcfu_2fupi
481 .Lcfu_2nowords: mov     r3, r7, get_byte_2
482                 teq     ip, #0
483                 beq     .Lcfu_finished
484                 cmp     ip, #2
485                 strb    r3, [r0], #1
486                 movge   r3, r7, get_byte_3
487                 strgeb  r3, [r0], #1
488 USER(           ldrgtbt r3, [r1], #0)                   @ May fault
489                 strgtb  r3, [r0], #1
490                 b       .Lcfu_finished
491
492 .Lcfu_3fupi:    subs    r2, r2, #4
493                 addmi   ip, r2, #4
494                 bmi     .Lcfu_3nowords
495                 mov     r3, r7, pull #24
496 USER(           ldrt    r7, [r1], #4)                   @ May fault
497                 orr     r3, r3, r7, push #8
498                 str     r3, [r0], #4
499                 mov     ip, r1, lsl #32 - PAGE_SHIFT
500                 rsb     ip, ip, #0
501                 movs    ip, ip, lsr #32 - PAGE_SHIFT
502                 beq     .Lcfu_3fupi
503                 cmp     r2, ip
504                 movlt   ip, r2
505                 sub     r2, r2, ip
506                 subs    ip, ip, #16
507                 blt     .Lcfu_3rem8lp
508
509 .Lcfu_3cpy8lp:  mov     r3, r7, pull #24
510                 ldmia   r1!, {r4 - r7}                  @ Shouldnt fault
511                 orr     r3, r3, r4, push #8
512                 mov     r4, r4, pull #24
513                 orr     r4, r4, r5, push #8
514                 mov     r5, r5, pull #24
515                 orr     r5, r5, r6, push #8
516                 mov     r6, r6, pull #24
517                 orr     r6, r6, r7, push #8
518                 stmia   r0!, {r3 - r6}
519                 subs    ip, ip, #16
520                 bpl     .Lcfu_3cpy8lp
521
522 .Lcfu_3rem8lp:  tst     ip, #8
523                 movne   r3, r7, pull #24
524                 ldmneia r1!, {r4, r7}                   @ Shouldnt fault
525                 orrne   r3, r3, r4, push #8
526                 movne   r4, r4, pull #24
527                 orrne   r4, r4, r7, push #8
528                 stmneia r0!, {r3 - r4}
529                 tst     ip, #4
530                 movne   r3, r7, pull #24
531 USER(           ldrnet  r7, [r1], #4)                   @ May fault
532                 orrne   r3, r3, r7, push #8
533                 strne   r3, [r0], #4
534                 ands    ip, ip, #3
535                 beq     .Lcfu_3fupi
536 .Lcfu_3nowords: mov     r3, r7, get_byte_3
537                 teq     ip, #0
538                 beq     .Lcfu_finished
539                 cmp     ip, #2
540                 strb    r3, [r0], #1
541 USER(           ldrgebt r3, [r1], #1)                   @ May fault
542                 strgeb  r3, [r0], #1
543 USER(           ldrgtbt r3, [r1], #1)                   @ May fault
544                 strgtb  r3, [r0], #1
545                 b       .Lcfu_finished
546 ENDPROC(__copy_from_user)
547
548                 .pushsection .fixup,"ax"
549                 .align  0
550                 /*
551                  * We took an exception.  r0 contains a pointer to
552                  * the byte not copied.
553                  */
554 9001:           ldr     r2, [sp], #4                    @ void *to
555                 sub     r2, r0, r2                      @ bytes copied
556                 ldr     r1, [sp], #4                    @ unsigned long count
557                 subs    r4, r1, r2                      @ bytes left to copy
558                 movne   r1, r4
559                 blne    __memzero
560                 mov     r0, r4
561                 ldmfd   sp!, {r4 - r7, pc}
562                 .popsection
563