source: trunk/minix/lib/i386/string/memchr.s@ 9

!       memchr()                                        Author: Kees J. Bot
!                                                               2 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
        .align  16
_memchr:
        push    ebp
        mov     ebp, esp
        push    edi
        mov     edi, 8(ebp)     ! edi = string
        movb    al, 12(ebp)     ! The character to look for
        mov     ecx, 16(ebp)    ! Length
        cmpb    cl, 1           ! 'Z' bit must be clear if ecx = 0
        cld
        repne
        scasb
        jne     failure
        lea     eax, -1(edi)    ! Found
        pop     edi
        pop     ebp
        ret
failure:xor     eax, eax
        pop     edi
        pop     ebp
        ret