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/*
* Defined in include/fbos/string.h
*
* size_t strlen(const char *str)
*
* Returns (a0): string length.
* Parameter (a0): string to measure.
* Clobbers: t0, t1.
*/
.globl strlen
.type strlen, @function
strlen:
mv t1, a0
1:
lbu t0, 0(t1)
beqz t0, 2f
addi t1, t1, 1
j 1b
2:
sub a0, t1, a0
ret
/*
* Defined in include/fbos/string.h
*
* int strcmp(const char *s1, const char *s2)
*
* Returns (a0): comparison result as in stdlib.
* Parameter (a0, a1): strings to compare.
* Clobbers: t0, t1.
*/
.globl strcmp
.type strcmp, @function
strcmp:
1:
lbu t0, 0(a0)
lbu t1, 0(a1)
addi a0, a0, 1
addi a1, a1, 1
bne t0, t1, 2f
bnez t0, 1b
li a0, 0
ret
2:
sub a0, t0, t1
ret
/*
* Defined in include/fbos/string.h
*
* int memcmp(const void *ptr1, const void *ptr2, size_t n)
*
* Returns (a0): comparison result as in stdlib.
* Parameters (a0, a1): strings to compare.
* Clobbers: t0, t1.
*/
.global memcmp
.type memcmp, @function
memcmp:
1:
lbu t0, 0(a0)
lbu t1, 0(a1)
bne t0, t1, 2f
addi a0, a0, 1
addi a1, a1, 1
addi a2, a2, -1
bnez a2, 1b
li a0, 0
ret
2:
sub a0, t0, t1
ret
/*
* Defined in include/fbos/string.h
*
* void memcpy(const void *dest, const void *src, size_t count)
*
* Parameter a0: destination string.
* Parameter a1: source string.
* Parameter a2: number of bytes to copy.
* Clobbers: t0.
*/
.global memcpy
.type memcpy, @function
memcpy:
1:
beqz a2, 3f
2:
lbu t0, 0(a1)
sb t0, 0(a0)
addi a0, a0, 1
addi a1, a1, 1
addi a2, a2, -1
bnez a2, 2b
3:
ret
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