1/*
2 *  (c) Copyright 1986 HEWLETT-PACKARD COMPANY
3 *
4 *  To anyone who acknowledges that this file is provided "AS IS"
5 *  without any express or implied warranty:
6 *      permission to use, copy, modify, and distribute this file
7 *  for any purpose is hereby granted without fee, provided that
8 *  the above copyright notice and this notice appears in all
9 *  copies, and that the name of Hewlett-Packard Company not be
10 *  used in advertising or publicity pertaining to distribution
11 *  of the software without specific, written prior permission.
12 *  Hewlett-Packard Company makes no representations about the
13 *  suitability of this software for any purpose.
14 */
15
16/* SPECTRUM_ID: @(#)memchr.s	37.4     86/04/23 */
17/*
18 * memchr(s, c, n)
19 *
20 * returns pointer to first occurrence of char c
21 * in first n characters of memory area s,
22 * or null if c does not occur.
23 */
24
25#include "DEFS.h"
26
27#define FROM	arg0
28#define CHAR	arg1
29#define COUNT	arg2
30#define TEMP1	r19
31
32ENTRY(memchr)
33	comb,<=	COUNT,r0,memchrexit	/* return if count is zero */
34	copy	r0,ret0			/* null if c not found in n chars */
35	depi	0,23,24,CHAR		/* make char unsigned */
36
37	ldbs,ma	1(FROM),TEMP1
38memchrloop:
39	comb,=,n	TEMP1,CHAR,memchrequal
40	addib,<>	-1,COUNT,memchrloop
41	ldbs,ma	1(FROM),TEMP1
42	b,n	memchrexit
43
44memchrequal:
45	ldo	-1(FROM),ret0
46
47memchrexit:
48EXIT(memchr)
49