Initial revision

lib/i86/string/_strnlen.s

@@ -0,0 +1,26 @@
+!	_strnlen()					Author: Kees J. Bot
+!								27 Jan 1994
+.sect .text; .sect .rom; .sect .data; .sect .bss
+
+! size_t _strnlen(const char *s, size_t cx)
+!	Return the length of a string.
+!
+.sect .text
+.define __strnlen
+__strnlen:
+	push	bp
+	mov	bp, sp
+	push	di
+	mov	di, 4(bp)	! di = string
+	xorb	al, al		! Look for a zero byte
+	mov	dx, cx		! Save maximum count
+	cmpb	cl, #1		! 'Z' bit must be clear if cx = 0
+	cld
+  repne	scasb			! Look for zero
+	jne	no0
+	inc	cx		! Don't count zero byte
+no0:	mov	ax, dx
+	sub	ax, cx		! Compute bytes scanned
+	pop	di
+	pop	bp
+	ret