minix/lib/i386/string/memchr.s

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2005-04-21 16:53:53 +02:00
! 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