minix/lib/i86/string/strrchr.s
2005-04-21 14:53:53 +00:00

33 lines
706 B
ArmAsm
Executable file

! strrchr() Author: Kees J. Bot
! 27 Jan 1994
.sect .text; .sect .rom; .sect .data; .sect .bss
! char *strrchr(const char *s, int c)
! Look for the last occurrence a character in a string.
!
.sect .text
.define _strrchr
_strrchr:
push bp
mov bp, sp
push di
mov di, 4(bp) ! di = string
mov cx, #-1
xorb al, al
cld
repne scasb ! Look for the end of the string
not cx ! -1 - cx = Length of the string + null
dec di ! Put di back on the zero byte
movb al, 6(bp) ! The character to look for
std ! Downwards search
repne scasb
cld ! Direction bit back to default
jne failure
lea ax, 1(di) ! Found it
pop di
pop bp
ret
failure:xor ax, ax ! Not there
pop di
pop bp
ret