NetBSD/lib/libc/arch/i386/string/memchr.S

/*
 * Written by J.T. Conklin <jtc@netbsd.org>.
 * Public domain.
 */

#include <machine/asm.h>

#if defined(LIBC_SCCS)
	RCSID("$Id: memchr.S,v 1.7 1995/04/28 22:54:15 jtc Exp $")
#endif

ENTRY(memchr)
	pushl	%edi
	movl	8(%esp),%edi		/* string address */
	movl	12(%esp),%eax		/* set character to search for */
	movl	16(%esp),%ecx		/* set length of search */
	testl	%ecx,%ecx		/* test for len == 0 */
	jz	L1
	cld				/* set search forward */
	repne				/* search! */
	scasb
	jne	L1			/* scan failed, return null */
	leal	-1(%edi),%eax		/* adjust result of scan */
	popl	%edi
	ret
	.align 2,0x90
L1:	xorl	%eax,%eax
	popl	%edi
	ret
make an arch directory in libc, and move all machine dirs into it 1993-10-07 03:17:24 +03:00			`/*`
Winning Strategies has placed this code into the Public Domain 1995-04-29 02:53:59 +04:00			`* Written by J.T. Conklin <jtc@netbsd.org>.`
			`* Public domain.`
make an arch directory in libc, and move all machine dirs into it 1993-10-07 03:17:24 +03:00			`*/`

Use RCSID macro for RCS ID's. 1994-03-12 04:39:55 +03:00			`#include <machine/asm.h>`

Change instances of LIBC_RCS back to LIBC_SCCS. If we are going to change th LIBC_RCS, the entire source tree should be updated at once. Remove && !defined(lint) from conditionals around rcs id's. No one is ever going to pass a *.s file through lint. 1993-10-21 04:39:55 +03:00			`#if defined(LIBC_SCCS)`
Winning Strategies has placed this code into the Public Domain 1995-04-29 02:53:59 +04:00			`RCSID("$Id: memchr.S,v 1.7 1995/04/28 22:54:15 jtc Exp $")`
Change instances of LIBC_RCS back to LIBC_SCCS. If we are going to change th LIBC_RCS, the entire source tree should be updated at once. Remove && !defined(lint) from conditionals around rcs id's. No one is ever going to pass a *.s file through lint. 1993-10-21 04:39:55 +03:00			`#endif`
make an arch directory in libc, and move all machine dirs into it 1993-10-07 03:17:24 +03:00
			`ENTRY(memchr)`
			`pushl %edi`
			`movl 8(%esp),%edi /* string address */`
			`movl 12(%esp),%eax /* set character to search for */`
			`movl 16(%esp),%ecx /* set length of search */`
If len == 0, then the result must be 0 regardless of the other arguments. 1994-11-24 19:36:35 +03:00			`testl %ecx,%ecx /* test for len == 0 */`
			`jz L1`
make an arch directory in libc, and move all machine dirs into it 1993-10-07 03:17:24 +03:00			`cld /* set search forward */`
			`repne /* search! */`
			`scasb`
Style police. Use `je' and `jne' only on the result of an equality test; use `jz' and `jnz' in all other cases. 1994-02-14 23:05:52 +03:00			`jne L1 /* scan failed, return null */`
make an arch directory in libc, and move all machine dirs into it 1993-10-07 03:17:24 +03:00			`leal -1(%edi),%eax /* adjust result of scan */`
			`popl %edi`
			`ret`
			`.align 2,0x90`
			`L1: xorl %eax,%eax`
			`popl %edi`
			`ret`