forked from KolibriOS/kolibrios
31 lines
823 B
ArmAsm
31 lines
823 B
ArmAsm
|
# _strnlen() Author: Kees J. Bot 1 Jan 1994
|
||
|
|
|
||
|
|
# size_t _strnlen(const char *s, size_t ecx)
|
||
|
|
# Return the length of a string.
|
||
|
|
|
||
|
|
.intel_syntax
|
||
|
|
|
||
|
|
.globl __strnlen
|
||
|
|
|
||
|
|
.text
|
||
|
|
.align 16
|
||
|
|
__strnlen:
|
||
|
|
push ebp
|
||
|
|
mov ebp, esp
|
||
|
|
push edi
|
||
|
|
mov edi, [ebp+8] # edi = string
|
||
|
|
xorb al, al # Look for a zero byte
|
||
|
|
mov edx, ecx # Save maximum count
|
||
|
|
cmpb cl, 1 # 'Z' bit must be clear if ecx = 0
|
||
|
|
cld
|
||
|
|
repne
|
||
|
|
scasb # Look for zero
|
||
|
|
jne no0
|
||
|
|
inc ecx # Don't count zero byte
|
||
|
|
no0:
|
||
|
|
mov eax, edx
|
||
|
|
sub eax, ecx # Compute bytes scanned
|
||
|
|
pop edi
|
||
|
|
pop ebp
|
||
|
|
ret
|