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/*
 *  (c) Copyright 1986 HEWLETT-PACKARD COMPANY
 *
 *  To anyone who acknowledges that this file is provided "AS IS"
 *  without any express or implied warranty:
 *      permission to use, copy, modify, and distribute this file
 *  for any purpose is hereby granted without fee, provided that
 *  the above copyright notice and this notice appears in all
 *  copies, and that the name of Hewlett-Packard Company not be
 *  used in advertising or publicity pertaining to distribution
 *  of the software without specific, written prior permission.
 *  Hewlett-Packard Company makes no representations about the
 *  suitability of this software for any purpose.
 */

/* SPECTRUM_ID: @(#)memchr.s    37.4     86/04/23 */
/*
 * memchr(s, c, n)
 *
 * returns pointer to first occurrence of char c
 * in first n characters of memory area s,
 * or null if c does not occur.
 */

#include "DEFS.h"

#define FROM    arg0
#define CHAR    arg1
#define COUNT   arg2
#define TEMP1   r19

ENTRY(memchr)
        comb,<= COUNT,r0,memchrexit     /* return if count is zero */
        copy    r0,ret0                 /* null if c not found in n chars */
        depi    0,23,24,CHAR            /* make char unsigned */

        ldbs,ma 1(FROM),TEMP1
memchrloop:
        comb,=,n        TEMP1,CHAR,memchrequal
        addib,<>        -1,COUNT,memchrloop
        ldbs,ma 1(FROM),TEMP1
        b,n     memchrexit

memchrequal:
        ldo     -1(FROM),ret0

memchrexit:
EXIT(memchr)