diff --git a/libc/arch-x86/string/bcmp.S b/libc/arch-x86/string/bcmp.S
new file mode 100644
index 0000000..a5b46ae
--- /dev/null
+++ b/libc/arch-x86/string/bcmp.S
@@ -0,0 +1,32 @@
+/*	$OpenBSD: bcmp.S,v 1.3 2005/08/07 11:30:38 espie Exp $ */
+/*
+ * Written by J.T. Conklin <jtc@netbsd.org>.
+ * Public domain.
+ */
+
+#include <machine/asm.h>
+
+ENTRY(bcmp)
+	pushl	%edi
+	pushl	%esi
+	movl	12(%esp),%edi
+	movl	16(%esp),%esi
+	xorl	%eax,%eax		/* clear return value */
+	cld				/* set compare direction forward */
+
+	movl	20(%esp),%ecx		/* compare by words */
+	shrl	$2,%ecx
+	repe
+	cmpsl
+	jne	L1
+
+	movl	20(%esp),%ecx		/* compare remainder by bytes */
+	andl	$3,%ecx
+	repe
+	cmpsb
+	je	L2
+
+L1:	incl	%eax
+L2:	popl	%esi
+	popl	%edi
+	ret