Initial revision

lib/i386/string/strchr.s

@@ -0,0 +1,41 @@
+!	strchr()					Author: Kees J. Bot
+!								1 Jan 1994
+.sect .text; .sect .rom; .sect .data; .sect .bss
+
+! char *strchr(const char *s, int c)
+!	Look for a character in a string.
+!
+.sect .text
+.define _strchr
+	.align	16
+_strchr:
+	push	ebp
+	mov	ebp, esp
+	push	edi
+	cld
+	mov	edi, 8(ebp)	! edi = string
+	mov	edx, 16		! Look at small chunks of the string
+next:	shl	edx, 1		! Chunks become bigger each time
+	mov	ecx, edx
+	xorb	al, al		! Look for the zero at the end
+	repne
+	scasb
+	pushf			! Remember the flags
+	sub	ecx, edx
+	neg	ecx		! Some or all of the chunk
+	sub	edi, ecx	! Step back
+	movb	al, 12(ebp)	! The character to look for
+	repne
+	scasb
+	je	found
+	popf			! Did we find the end of string earlier?
+	jne	next		! No, try again
+	xor	eax, eax	! Return NULL
+	pop	edi
+	pop	ebp
+	ret
+found:	pop	eax		! Get rid of those flags
+	lea	eax, -1(edi)	! Address of byte found
+	pop	edi
+	pop	ebp
+	ret