42 lines
753 B
ArmAsm
42 lines
753 B
ArmAsm
.file "strncmp.S"
|
|
|
|
.section .text
|
|
.global _strncmp
|
|
.type _strncmp,@function
|
|
_strncmp:
|
|
;; R1: string1
|
|
;; R2: string2
|
|
;; R3: max number of bytes to compare
|
|
#ifdef __RX_DISALLOW_STRING_INSNS__
|
|
cmp #0, r3 ; For a length of zero, return zero
|
|
beq 4f
|
|
|
|
2: mov.b [r1+], r4
|
|
mov.b [r2+], r5
|
|
cmp #0, r4
|
|
beq 3f
|
|
cmp #0, r5
|
|
beq 3f
|
|
sub #1, r3
|
|
beq 3f
|
|
cmp r4, r5
|
|
beq 2b
|
|
|
|
3: and #0xff, r4 ; We need to perform an unsigned comparison of the bytes.
|
|
and #0xff, r5
|
|
sub r5, r4, r1
|
|
rts
|
|
|
|
4: mov #0, r1
|
|
rts
|
|
#else
|
|
scmpu ; Perform the string comparison
|
|
bnc 1f ; If Carry is not set skip over
|
|
scne.L r1 ; Set result based on Z flag
|
|
rts ;
|
|
1: ;
|
|
mov #-1,r1 ; Carry not set, result should be negative
|
|
rts ;
|
|
#endif
|
|
.size _strncmp, . - _strncmp
|