27 lines
559 B
ArmAsm
Executable file
27 lines
559 B
ArmAsm
Executable file
! _strnlen() Author: Kees J. Bot
|
|
! 27 Jan 1994
|
|
.sect .text; .sect .rom; .sect .data; .sect .bss
|
|
|
|
! size_t _strnlen(const char *s, size_t cx)
|
|
! Return the length of a string.
|
|
!
|
|
.sect .text
|
|
.define __strnlen
|
|
__strnlen:
|
|
push bp
|
|
mov bp, sp
|
|
push di
|
|
mov di, 4(bp) ! di = string
|
|
xorb al, al ! Look for a zero byte
|
|
mov dx, cx ! Save maximum count
|
|
cmpb cl, #1 ! 'Z' bit must be clear if cx = 0
|
|
cld
|
|
repne scasb ! Look for zero
|
|
jne no0
|
|
inc cx ! Don't count zero byte
|
|
no0: mov ax, dx
|
|
sub ax, cx ! Compute bytes scanned
|
|
pop di
|
|
pop bp
|
|
ret
|