add memchr to libkern

2 files changed, 29 insertions, 1 deletions

diff --git a/sys/lib/libkern/arch/i386/Makefile.inc b/sys/lib/libkern/arch/i386/Makefile.inc
index 857134d5146..e048a85a5de 100644
--- a/sys/lib/libkern/arch/i386/Makefile.inc
+++ b/sys/lib/libkern/arch/i386/Makefile.inc
@@ -1,7 +1,8 @@
-#	$OpenBSD: Makefile.inc,v 1.4 1996/04/21 22:27:52 deraadt Exp $
+#	$OpenBSD: Makefile.inc,v 1.5 1997/11/04 19:08:05 chuck Exp $
 #	$NetBSD: Makefile.inc,v 1.10 1996/04/13 01:17:41 cgd Exp $
 
 SRCS+=	__main.c imax.c imin.c lmax.c lmin.c max.c min.c ulmax.c ulmin.c \
+	memchr.S \
 	bcmp.S ffs.S memset.S strcat.S strcmp.S strcpy.S strlen.S strncmp.c \
 	strncpy.c scanc.S skpc.S locc.S htonl.S htons.S ntohl.S ntohs.S \
 	strncasecmp.c
diff --git a/sys/lib/libkern/arch/i386/memchr.S b/sys/lib/libkern/arch/i386/memchr.S
new file mode 100644
index 00000000000..43f7a91e0a1
--- /dev/null
+++ b/sys/lib/libkern/arch/i386/memchr.S
@@ -0,0 +1,27 @@
+/*	$OpenBSD: memchr.S,v 1.1 1997/11/04 19:08:06 chuck Exp $	*/
+
+/*
+ * Written by J.T. Conklin <jtc@netbsd.org>.
+ * Public domain.
+ */
+
+#include <machine/asm.h>
+
+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