minix/lib/libc/arch/i386/string/memchr.S
Arun Thomas 9a21d1a2fd Macros for symbols used in both ASM and C
-The macros take care of prepending the leading underscore when
 necessary.
2010-08-17 16:44:07 +00:00

29 lines
568 B
ArmAsm

/* memchr() Author: Kees J. Bot */
/* 2 Jan 1994 */
/* void *memchr(const void *s, int c, size_t n) */
/* Look for a character in a chunk of memory. */
/* */
#include <machine/asm.h>
ENTRY(memchr)
push %ebp
movl %esp, %ebp
push %edi
movl 8(%ebp), %edi /* edi = string */
movb 12(%ebp), %al /* The character to look for */
movl 16(%ebp), %ecx /* Length */
cmpb $1, %cl /* 'Z' bit must be clear if ecx = 0 */
cld
repne scasb
jne failure
leal -1(%edi), %eax /* Found */
pop %edi
pop %ebp
ret
failure:
xorl %eax, %eax
pop %edi
pop %ebp
ret