1 /* $OpenBSD: memchr.S,v 1.3 2005/08/07 11:30:38 espie Exp $ */ 2 /* 3 * Written by J.T. Conklin <jtc (at) netbsd.org>. 4 * Public domain. 5 */ 6 7 #include <machine/asm.h> 8 9 ENTRY(memchr) 10 pushl %edi 11 movl 8(%esp),%edi /* string address */ 12 movl 12(%esp),%eax /* set character to search for */ 13 movl 16(%esp),%ecx /* set length of search */ 14 testl %ecx,%ecx /* test for len == 0 */ 15 jz L1 16 cld /* set search forward */ 17 repne /* search! */ 18 scasb 19 jne L1 /* scan failed, return null */ 20 leal -1(%edi),%eax /* adjust result of scan */ 21 popl %edi 22 ret 23 .align 2,0x90 24 L1: xorl %eax,%eax 25 popl %edi 26 ret 27
