719 lines
12 KiB
ArmAsm
719 lines
12 KiB
ArmAsm
/*
|
|
* String handling functions for PowerPC.
|
|
*
|
|
* Copyright (C) 1996 Paul Mackerras.
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version
|
|
* 2 of the License, or (at your option) any later version.
|
|
*/
|
|
#include <asm/processor.h>
|
|
#include <asm/cache.h>
|
|
#include <asm/errno.h>
|
|
#include <asm/ppc_asm.h>
|
|
|
|
#define COPY_16_BYTES \
|
|
lwz r7,4(r4); \
|
|
lwz r8,8(r4); \
|
|
lwz r9,12(r4); \
|
|
lwzu r10,16(r4); \
|
|
stw r7,4(r6); \
|
|
stw r8,8(r6); \
|
|
stw r9,12(r6); \
|
|
stwu r10,16(r6)
|
|
|
|
#define COPY_16_BYTES_WITHEX(n) \
|
|
8 ## n ## 0: \
|
|
lwz r7,4(r4); \
|
|
8 ## n ## 1: \
|
|
lwz r8,8(r4); \
|
|
8 ## n ## 2: \
|
|
lwz r9,12(r4); \
|
|
8 ## n ## 3: \
|
|
lwzu r10,16(r4); \
|
|
8 ## n ## 4: \
|
|
stw r7,4(r6); \
|
|
8 ## n ## 5: \
|
|
stw r8,8(r6); \
|
|
8 ## n ## 6: \
|
|
stw r9,12(r6); \
|
|
8 ## n ## 7: \
|
|
stwu r10,16(r6)
|
|
|
|
#define COPY_16_BYTES_EXCODE(n) \
|
|
9 ## n ## 0: \
|
|
addi r5,r5,-(16 * n); \
|
|
b 104f; \
|
|
9 ## n ## 1: \
|
|
addi r5,r5,-(16 * n); \
|
|
b 105f; \
|
|
.section __ex_table,"a"; \
|
|
.align 2; \
|
|
.long 8 ## n ## 0b,9 ## n ## 0b; \
|
|
.long 8 ## n ## 1b,9 ## n ## 0b; \
|
|
.long 8 ## n ## 2b,9 ## n ## 0b; \
|
|
.long 8 ## n ## 3b,9 ## n ## 0b; \
|
|
.long 8 ## n ## 4b,9 ## n ## 1b; \
|
|
.long 8 ## n ## 5b,9 ## n ## 1b; \
|
|
.long 8 ## n ## 6b,9 ## n ## 1b; \
|
|
.long 8 ## n ## 7b,9 ## n ## 1b; \
|
|
.text
|
|
|
|
.text
|
|
.stabs "arch/ppc/lib/",N_SO,0,0,0f
|
|
.stabs "string.S",N_SO,0,0,0f
|
|
|
|
CACHELINE_BYTES = L1_CACHE_BYTES
|
|
LG_CACHELINE_BYTES = L1_CACHE_SHIFT
|
|
CACHELINE_MASK = (L1_CACHE_BYTES-1)
|
|
|
|
_GLOBAL(strcpy)
|
|
addi r5,r3,-1
|
|
addi r4,r4,-1
|
|
1: lbzu r0,1(r4)
|
|
cmpwi 0,r0,0
|
|
stbu r0,1(r5)
|
|
bne 1b
|
|
blr
|
|
|
|
/* This clears out any unused part of the destination buffer,
|
|
just as the libc version does. -- paulus */
|
|
_GLOBAL(strncpy)
|
|
cmpwi 0,r5,0
|
|
beqlr
|
|
mtctr r5
|
|
addi r6,r3,-1
|
|
addi r4,r4,-1
|
|
1: lbzu r0,1(r4)
|
|
cmpwi 0,r0,0
|
|
stbu r0,1(r6)
|
|
bdnzf 2,1b /* dec ctr, branch if ctr != 0 && !cr0.eq */
|
|
bnelr /* if we didn't hit a null char, we're done */
|
|
mfctr r5
|
|
cmpwi 0,r5,0 /* any space left in destination buffer? */
|
|
beqlr /* we know r0 == 0 here */
|
|
2: stbu r0,1(r6) /* clear it out if so */
|
|
bdnz 2b
|
|
blr
|
|
|
|
_GLOBAL(strcat)
|
|
addi r5,r3,-1
|
|
addi r4,r4,-1
|
|
1: lbzu r0,1(r5)
|
|
cmpwi 0,r0,0
|
|
bne 1b
|
|
addi r5,r5,-1
|
|
1: lbzu r0,1(r4)
|
|
cmpwi 0,r0,0
|
|
stbu r0,1(r5)
|
|
bne 1b
|
|
blr
|
|
|
|
_GLOBAL(strcmp)
|
|
addi r5,r3,-1
|
|
addi r4,r4,-1
|
|
1: lbzu r3,1(r5)
|
|
cmpwi 1,r3,0
|
|
lbzu r0,1(r4)
|
|
subf. r3,r0,r3
|
|
beqlr 1
|
|
beq 1b
|
|
blr
|
|
|
|
_GLOBAL(strlen)
|
|
addi r4,r3,-1
|
|
1: lbzu r0,1(r4)
|
|
cmpwi 0,r0,0
|
|
bne 1b
|
|
subf r3,r3,r4
|
|
blr
|
|
|
|
/*
|
|
* Use dcbz on the complete cache lines in the destination
|
|
* to set them to zero. This requires that the destination
|
|
* area is cacheable. -- paulus
|
|
*/
|
|
_GLOBAL(cacheable_memzero)
|
|
mr r5,r4
|
|
li r4,0
|
|
addi r6,r3,-4
|
|
cmplwi 0,r5,4
|
|
blt 7f
|
|
stwu r4,4(r6)
|
|
beqlr
|
|
andi. r0,r6,3
|
|
add r5,r0,r5
|
|
subf r6,r0,r6
|
|
clrlwi r7,r6,32-LG_CACHELINE_BYTES
|
|
add r8,r7,r5
|
|
srwi r9,r8,LG_CACHELINE_BYTES
|
|
addic. r9,r9,-1 /* total number of complete cachelines */
|
|
ble 2f
|
|
xori r0,r7,CACHELINE_MASK & ~3
|
|
srwi. r0,r0,2
|
|
beq 3f
|
|
mtctr r0
|
|
4: stwu r4,4(r6)
|
|
bdnz 4b
|
|
3: mtctr r9
|
|
li r7,4
|
|
#if !defined(CONFIG_8xx)
|
|
10: dcbz r7,r6
|
|
#else
|
|
10: stw r4, 4(r6)
|
|
stw r4, 8(r6)
|
|
stw r4, 12(r6)
|
|
stw r4, 16(r6)
|
|
#if CACHE_LINE_SIZE >= 32
|
|
stw r4, 20(r6)
|
|
stw r4, 24(r6)
|
|
stw r4, 28(r6)
|
|
stw r4, 32(r6)
|
|
#endif /* CACHE_LINE_SIZE */
|
|
#endif
|
|
addi r6,r6,CACHELINE_BYTES
|
|
bdnz 10b
|
|
clrlwi r5,r8,32-LG_CACHELINE_BYTES
|
|
addi r5,r5,4
|
|
2: srwi r0,r5,2
|
|
mtctr r0
|
|
bdz 6f
|
|
1: stwu r4,4(r6)
|
|
bdnz 1b
|
|
6: andi. r5,r5,3
|
|
7: cmpwi 0,r5,0
|
|
beqlr
|
|
mtctr r5
|
|
addi r6,r6,3
|
|
8: stbu r4,1(r6)
|
|
bdnz 8b
|
|
blr
|
|
|
|
_GLOBAL(memset)
|
|
rlwimi r4,r4,8,16,23
|
|
rlwimi r4,r4,16,0,15
|
|
addi r6,r3,-4
|
|
cmplwi 0,r5,4
|
|
blt 7f
|
|
stwu r4,4(r6)
|
|
beqlr
|
|
andi. r0,r6,3
|
|
add r5,r0,r5
|
|
subf r6,r0,r6
|
|
srwi r0,r5,2
|
|
mtctr r0
|
|
bdz 6f
|
|
1: stwu r4,4(r6)
|
|
bdnz 1b
|
|
6: andi. r5,r5,3
|
|
7: cmpwi 0,r5,0
|
|
beqlr
|
|
mtctr r5
|
|
addi r6,r6,3
|
|
8: stbu r4,1(r6)
|
|
bdnz 8b
|
|
blr
|
|
|
|
/*
|
|
* This version uses dcbz on the complete cache lines in the
|
|
* destination area to reduce memory traffic. This requires that
|
|
* the destination area is cacheable.
|
|
* We only use this version if the source and dest don't overlap.
|
|
* -- paulus.
|
|
*/
|
|
_GLOBAL(cacheable_memcpy)
|
|
add r7,r3,r5 /* test if the src & dst overlap */
|
|
add r8,r4,r5
|
|
cmplw 0,r4,r7
|
|
cmplw 1,r3,r8
|
|
crand 0,0,4 /* cr0.lt &= cr1.lt */
|
|
blt memcpy /* if regions overlap */
|
|
|
|
addi r4,r4,-4
|
|
addi r6,r3,-4
|
|
neg r0,r3
|
|
andi. r0,r0,CACHELINE_MASK /* # bytes to start of cache line */
|
|
beq 58f
|
|
|
|
cmplw 0,r5,r0 /* is this more than total to do? */
|
|
blt 63f /* if not much to do */
|
|
andi. r8,r0,3 /* get it word-aligned first */
|
|
subf r5,r0,r5
|
|
mtctr r8
|
|
beq+ 61f
|
|
70: lbz r9,4(r4) /* do some bytes */
|
|
stb r9,4(r6)
|
|
addi r4,r4,1
|
|
addi r6,r6,1
|
|
bdnz 70b
|
|
61: srwi. r0,r0,2
|
|
mtctr r0
|
|
beq 58f
|
|
72: lwzu r9,4(r4) /* do some words */
|
|
stwu r9,4(r6)
|
|
bdnz 72b
|
|
|
|
58: srwi. r0,r5,LG_CACHELINE_BYTES /* # complete cachelines */
|
|
clrlwi r5,r5,32-LG_CACHELINE_BYTES
|
|
li r11,4
|
|
mtctr r0
|
|
beq 63f
|
|
53:
|
|
#if !defined(CONFIG_8xx)
|
|
dcbz r11,r6
|
|
#endif
|
|
COPY_16_BYTES
|
|
#if L1_CACHE_BYTES >= 32
|
|
COPY_16_BYTES
|
|
#if L1_CACHE_BYTES >= 64
|
|
COPY_16_BYTES
|
|
COPY_16_BYTES
|
|
#if L1_CACHE_BYTES >= 128
|
|
COPY_16_BYTES
|
|
COPY_16_BYTES
|
|
COPY_16_BYTES
|
|
COPY_16_BYTES
|
|
#endif
|
|
#endif
|
|
#endif
|
|
bdnz 53b
|
|
|
|
63: srwi. r0,r5,2
|
|
mtctr r0
|
|
beq 64f
|
|
30: lwzu r0,4(r4)
|
|
stwu r0,4(r6)
|
|
bdnz 30b
|
|
|
|
64: andi. r0,r5,3
|
|
mtctr r0
|
|
beq+ 65f
|
|
40: lbz r0,4(r4)
|
|
stb r0,4(r6)
|
|
addi r4,r4,1
|
|
addi r6,r6,1
|
|
bdnz 40b
|
|
65: blr
|
|
|
|
_GLOBAL(memmove)
|
|
cmplw 0,r3,r4
|
|
bgt backwards_memcpy
|
|
/* fall through */
|
|
|
|
_GLOBAL(memcpy)
|
|
srwi. r7,r5,3
|
|
addi r6,r3,-4
|
|
addi r4,r4,-4
|
|
beq 2f /* if less than 8 bytes to do */
|
|
andi. r0,r6,3 /* get dest word aligned */
|
|
mtctr r7
|
|
bne 5f
|
|
1: lwz r7,4(r4)
|
|
lwzu r8,8(r4)
|
|
stw r7,4(r6)
|
|
stwu r8,8(r6)
|
|
bdnz 1b
|
|
andi. r5,r5,7
|
|
2: cmplwi 0,r5,4
|
|
blt 3f
|
|
lwzu r0,4(r4)
|
|
addi r5,r5,-4
|
|
stwu r0,4(r6)
|
|
3: cmpwi 0,r5,0
|
|
beqlr
|
|
mtctr r5
|
|
addi r4,r4,3
|
|
addi r6,r6,3
|
|
4: lbzu r0,1(r4)
|
|
stbu r0,1(r6)
|
|
bdnz 4b
|
|
blr
|
|
5: subfic r0,r0,4
|
|
mtctr r0
|
|
6: lbz r7,4(r4)
|
|
addi r4,r4,1
|
|
stb r7,4(r6)
|
|
addi r6,r6,1
|
|
bdnz 6b
|
|
subf r5,r0,r5
|
|
rlwinm. r7,r5,32-3,3,31
|
|
beq 2b
|
|
mtctr r7
|
|
b 1b
|
|
|
|
_GLOBAL(backwards_memcpy)
|
|
rlwinm. r7,r5,32-3,3,31 /* r0 = r5 >> 3 */
|
|
add r6,r3,r5
|
|
add r4,r4,r5
|
|
beq 2f
|
|
andi. r0,r6,3
|
|
mtctr r7
|
|
bne 5f
|
|
1: lwz r7,-4(r4)
|
|
lwzu r8,-8(r4)
|
|
stw r7,-4(r6)
|
|
stwu r8,-8(r6)
|
|
bdnz 1b
|
|
andi. r5,r5,7
|
|
2: cmplwi 0,r5,4
|
|
blt 3f
|
|
lwzu r0,-4(r4)
|
|
subi r5,r5,4
|
|
stwu r0,-4(r6)
|
|
3: cmpwi 0,r5,0
|
|
beqlr
|
|
mtctr r5
|
|
4: lbzu r0,-1(r4)
|
|
stbu r0,-1(r6)
|
|
bdnz 4b
|
|
blr
|
|
5: mtctr r0
|
|
6: lbzu r7,-1(r4)
|
|
stbu r7,-1(r6)
|
|
bdnz 6b
|
|
subf r5,r0,r5
|
|
rlwinm. r7,r5,32-3,3,31
|
|
beq 2b
|
|
mtctr r7
|
|
b 1b
|
|
|
|
_GLOBAL(memcmp)
|
|
cmpwi 0,r5,0
|
|
ble- 2f
|
|
mtctr r5
|
|
addi r6,r3,-1
|
|
addi r4,r4,-1
|
|
1: lbzu r3,1(r6)
|
|
lbzu r0,1(r4)
|
|
subf. r3,r0,r3
|
|
bdnzt 2,1b
|
|
blr
|
|
2: li r3,0
|
|
blr
|
|
|
|
_GLOBAL(memchr)
|
|
cmpwi 0,r5,0
|
|
ble- 2f
|
|
mtctr r5
|
|
addi r3,r3,-1
|
|
1: lbzu r0,1(r3)
|
|
cmpw 0,r0,r4
|
|
bdnzf 2,1b
|
|
beqlr
|
|
2: li r3,0
|
|
blr
|
|
|
|
_GLOBAL(__copy_tofrom_user)
|
|
addi r4,r4,-4
|
|
addi r6,r3,-4
|
|
neg r0,r3
|
|
andi. r0,r0,CACHELINE_MASK /* # bytes to start of cache line */
|
|
beq 58f
|
|
|
|
cmplw 0,r5,r0 /* is this more than total to do? */
|
|
blt 63f /* if not much to do */
|
|
andi. r8,r0,3 /* get it word-aligned first */
|
|
mtctr r8
|
|
beq+ 61f
|
|
70: lbz r9,4(r4) /* do some bytes */
|
|
71: stb r9,4(r6)
|
|
addi r4,r4,1
|
|
addi r6,r6,1
|
|
bdnz 70b
|
|
61: subf r5,r0,r5
|
|
srwi. r0,r0,2
|
|
mtctr r0
|
|
beq 58f
|
|
72: lwzu r9,4(r4) /* do some words */
|
|
73: stwu r9,4(r6)
|
|
bdnz 72b
|
|
|
|
.section __ex_table,"a"
|
|
.align 2
|
|
.long 70b,100f
|
|
.long 71b,101f
|
|
.long 72b,102f
|
|
.long 73b,103f
|
|
.text
|
|
|
|
58: srwi. r0,r5,LG_CACHELINE_BYTES /* # complete cachelines */
|
|
clrlwi r5,r5,32-LG_CACHELINE_BYTES
|
|
li r11,4
|
|
beq 63f
|
|
|
|
#ifdef CONFIG_8xx
|
|
/* Don't use prefetch on 8xx */
|
|
mtctr r0
|
|
li r0,0
|
|
53: COPY_16_BYTES_WITHEX(0)
|
|
bdnz 53b
|
|
|
|
#else /* not CONFIG_8xx */
|
|
/* Here we decide how far ahead to prefetch the source */
|
|
li r3,4
|
|
cmpwi r0,1
|
|
li r7,0
|
|
ble 114f
|
|
li r7,1
|
|
#if MAX_COPY_PREFETCH > 1
|
|
/* Heuristically, for large transfers we prefetch
|
|
MAX_COPY_PREFETCH cachelines ahead. For small transfers
|
|
we prefetch 1 cacheline ahead. */
|
|
cmpwi r0,MAX_COPY_PREFETCH
|
|
ble 112f
|
|
li r7,MAX_COPY_PREFETCH
|
|
112: mtctr r7
|
|
111: dcbt r3,r4
|
|
addi r3,r3,CACHELINE_BYTES
|
|
bdnz 111b
|
|
#else
|
|
dcbt r3,r4
|
|
addi r3,r3,CACHELINE_BYTES
|
|
#endif /* MAX_COPY_PREFETCH > 1 */
|
|
|
|
114: subf r8,r7,r0
|
|
mr r0,r7
|
|
mtctr r8
|
|
|
|
53: dcbt r3,r4
|
|
54: dcbz r11,r6
|
|
.section __ex_table,"a"
|
|
.align 2
|
|
.long 54b,105f
|
|
.text
|
|
/* the main body of the cacheline loop */
|
|
COPY_16_BYTES_WITHEX(0)
|
|
#if L1_CACHE_BYTES >= 32
|
|
COPY_16_BYTES_WITHEX(1)
|
|
#if L1_CACHE_BYTES >= 64
|
|
COPY_16_BYTES_WITHEX(2)
|
|
COPY_16_BYTES_WITHEX(3)
|
|
#if L1_CACHE_BYTES >= 128
|
|
COPY_16_BYTES_WITHEX(4)
|
|
COPY_16_BYTES_WITHEX(5)
|
|
COPY_16_BYTES_WITHEX(6)
|
|
COPY_16_BYTES_WITHEX(7)
|
|
#endif
|
|
#endif
|
|
#endif
|
|
bdnz 53b
|
|
cmpwi r0,0
|
|
li r3,4
|
|
li r7,0
|
|
bne 114b
|
|
#endif /* CONFIG_8xx */
|
|
|
|
63: srwi. r0,r5,2
|
|
mtctr r0
|
|
beq 64f
|
|
30: lwzu r0,4(r4)
|
|
31: stwu r0,4(r6)
|
|
bdnz 30b
|
|
|
|
64: andi. r0,r5,3
|
|
mtctr r0
|
|
beq+ 65f
|
|
40: lbz r0,4(r4)
|
|
41: stb r0,4(r6)
|
|
addi r4,r4,1
|
|
addi r6,r6,1
|
|
bdnz 40b
|
|
65: li r3,0
|
|
blr
|
|
|
|
/* read fault, initial single-byte copy */
|
|
100: li r9,0
|
|
b 90f
|
|
/* write fault, initial single-byte copy */
|
|
101: li r9,1
|
|
90: subf r5,r8,r5
|
|
li r3,0
|
|
b 99f
|
|
/* read fault, initial word copy */
|
|
102: li r9,0
|
|
b 91f
|
|
/* write fault, initial word copy */
|
|
103: li r9,1
|
|
91: li r3,2
|
|
b 99f
|
|
|
|
/*
|
|
* this stuff handles faults in the cacheline loop and branches to either
|
|
* 104f (if in read part) or 105f (if in write part), after updating r5
|
|
*/
|
|
COPY_16_BYTES_EXCODE(0)
|
|
#if L1_CACHE_BYTES >= 32
|
|
COPY_16_BYTES_EXCODE(1)
|
|
#if L1_CACHE_BYTES >= 64
|
|
COPY_16_BYTES_EXCODE(2)
|
|
COPY_16_BYTES_EXCODE(3)
|
|
#if L1_CACHE_BYTES >= 128
|
|
COPY_16_BYTES_EXCODE(4)
|
|
COPY_16_BYTES_EXCODE(5)
|
|
COPY_16_BYTES_EXCODE(6)
|
|
COPY_16_BYTES_EXCODE(7)
|
|
#endif
|
|
#endif
|
|
#endif
|
|
|
|
/* read fault in cacheline loop */
|
|
104: li r9,0
|
|
b 92f
|
|
/* fault on dcbz (effectively a write fault) */
|
|
/* or write fault in cacheline loop */
|
|
105: li r9,1
|
|
92: li r3,LG_CACHELINE_BYTES
|
|
mfctr r8
|
|
add r0,r0,r8
|
|
b 106f
|
|
/* read fault in final word loop */
|
|
108: li r9,0
|
|
b 93f
|
|
/* write fault in final word loop */
|
|
109: li r9,1
|
|
93: andi. r5,r5,3
|
|
li r3,2
|
|
b 99f
|
|
/* read fault in final byte loop */
|
|
110: li r9,0
|
|
b 94f
|
|
/* write fault in final byte loop */
|
|
111: li r9,1
|
|
94: li r5,0
|
|
li r3,0
|
|
/*
|
|
* At this stage the number of bytes not copied is
|
|
* r5 + (ctr << r3), and r9 is 0 for read or 1 for write.
|
|
*/
|
|
99: mfctr r0
|
|
106: slw r3,r0,r3
|
|
add. r3,r3,r5
|
|
beq 120f /* shouldn't happen */
|
|
cmpwi 0,r9,0
|
|
bne 120f
|
|
/* for a read fault, first try to continue the copy one byte at a time */
|
|
mtctr r3
|
|
130: lbz r0,4(r4)
|
|
131: stb r0,4(r6)
|
|
addi r4,r4,1
|
|
addi r6,r6,1
|
|
bdnz 130b
|
|
/* then clear out the destination: r3 bytes starting at 4(r6) */
|
|
132: mfctr r3
|
|
srwi. r0,r3,2
|
|
li r9,0
|
|
mtctr r0
|
|
beq 113f
|
|
112: stwu r9,4(r6)
|
|
bdnz 112b
|
|
113: andi. r0,r3,3
|
|
mtctr r0
|
|
beq 120f
|
|
114: stb r9,4(r6)
|
|
addi r6,r6,1
|
|
bdnz 114b
|
|
120: blr
|
|
|
|
.section __ex_table,"a"
|
|
.align 2
|
|
.long 30b,108b
|
|
.long 31b,109b
|
|
.long 40b,110b
|
|
.long 41b,111b
|
|
.long 130b,132b
|
|
.long 131b,120b
|
|
.long 112b,120b
|
|
.long 114b,120b
|
|
.text
|
|
|
|
_GLOBAL(__clear_user)
|
|
addi r6,r3,-4
|
|
li r3,0
|
|
li r5,0
|
|
cmplwi 0,r4,4
|
|
blt 7f
|
|
/* clear a single word */
|
|
11: stwu r5,4(r6)
|
|
beqlr
|
|
/* clear word sized chunks */
|
|
andi. r0,r6,3
|
|
add r4,r0,r4
|
|
subf r6,r0,r6
|
|
srwi r0,r4,2
|
|
andi. r4,r4,3
|
|
mtctr r0
|
|
bdz 7f
|
|
1: stwu r5,4(r6)
|
|
bdnz 1b
|
|
/* clear byte sized chunks */
|
|
7: cmpwi 0,r4,0
|
|
beqlr
|
|
mtctr r4
|
|
addi r6,r6,3
|
|
8: stbu r5,1(r6)
|
|
bdnz 8b
|
|
blr
|
|
90: mr r3,r4
|
|
blr
|
|
91: mfctr r3
|
|
slwi r3,r3,2
|
|
add r3,r3,r4
|
|
blr
|
|
92: mfctr r3
|
|
blr
|
|
|
|
.section __ex_table,"a"
|
|
.align 2
|
|
.long 11b,90b
|
|
.long 1b,91b
|
|
.long 8b,92b
|
|
.text
|
|
|
|
_GLOBAL(__strncpy_from_user)
|
|
addi r6,r3,-1
|
|
addi r4,r4,-1
|
|
cmpwi 0,r5,0
|
|
beq 2f
|
|
mtctr r5
|
|
1: lbzu r0,1(r4)
|
|
cmpwi 0,r0,0
|
|
stbu r0,1(r6)
|
|
bdnzf 2,1b /* dec ctr, branch if ctr != 0 && !cr0.eq */
|
|
beq 3f
|
|
2: addi r6,r6,1
|
|
3: subf r3,r3,r6
|
|
blr
|
|
99: li r3,-EFAULT
|
|
blr
|
|
|
|
.section __ex_table,"a"
|
|
.align 2
|
|
.long 1b,99b
|
|
.text
|
|
|
|
/* r3 = str, r4 = len (> 0), r5 = top (highest addr) */
|
|
_GLOBAL(__strnlen_user)
|
|
addi r7,r3,-1
|
|
subf r6,r7,r5 /* top+1 - str */
|
|
cmplw 0,r4,r6
|
|
bge 0f
|
|
mr r6,r4
|
|
0: mtctr r6 /* ctr = min(len, top - str) */
|
|
1: lbzu r0,1(r7) /* get next byte */
|
|
cmpwi 0,r0,0
|
|
bdnzf 2,1b /* loop if --ctr != 0 && byte != 0 */
|
|
addi r7,r7,1
|
|
subf r3,r3,r7 /* number of bytes we have looked at */
|
|
beqlr /* return if we found a 0 byte */
|
|
cmpw 0,r3,r4 /* did we look at all len bytes? */
|
|
blt 99f /* if not, must have hit top */
|
|
addi r3,r4,1 /* return len + 1 to indicate no null found */
|
|
blr
|
|
99: li r3,0 /* bad address, return 0 */
|
|
blr
|
|
|
|
.section __ex_table,"a"
|
|
.align 2
|
|
.long 1b,99b
|