Initial revision

lib/i86/string/_strncat.s

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+!	_strncat()					Author: Kees J. Bot
+!								27 Jan 1994
+.sect .text; .sect .rom; .sect .data; .sect .bss
+
+! char *_strncat(char *s1, const char *s2, size_t dx)
+!	Append string s2 to s1.
+!
+.sect .text
+.define __strncat
+__strncat:
+	push	bp
+	mov	bp, sp
+	push	si
+	push	di
+	mov	di, 4(bp)	! String s1
+	mov	cx, #-1
+	xorb	al, al		! Null byte
+	cld
+  repne	scasb			! Look for the zero byte in s1
+	dec	di		! Back one up (and clear 'Z' flag)
+	push	di		! Save end of s1
+	mov	di, 6(bp)	! di = string s2
+	mov	cx, dx		! Maximum count
+  repne	scasb			! Look for the end of s2
+	jne	no0
+	inc	cx		! Exclude null byte
+no0:	sub	dx, cx		! Number of bytes in s2
+	mov	cx, dx
+	mov	si, 6(bp)	! si = string s2
+	pop	di		! di = end of string s1
+    rep	movsb			! Copy bytes
+	stosb			! Add a terminating null
+	mov	ax, 4(bp)	! Return s1
+	pop	di
+	pop	si
+	pop	bp
+	ret