source: trunk/minix/lib/i86/string/memchr.s@ 9

!       memchr()                                        Author: Kees J. Bot
!                                                               27 Jan 1994
.sect .text; .sect .rom; .sect .data; .sect .bss

! void *memchr(const void *s, int c, size_t n)
!       Look for a character in a chunk of memory.
!
.sect .text
.define _memchr
_memchr:
        push    bp
        mov     bp, sp
        push    di
        mov     di, 4(bp)       ! di = string
        movb    al, 6(bp)       ! The character to look for
        mov     cx, 8(bp)       ! Length
        cmpb    cl, #1          ! 'Z' bit must be clear if cx = 0
        cld
  repne scasb
        jne     failure
        lea     ax, -1(di)      ! Found
        pop     di
        pop     bp
        ret
failure:xor     ax, ax
        pop     di
        pop     bp
        ret