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/*-
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#if defined(LIBC_SCCS) && !defined(lint)
.asciz "@(#)memchr.s 5.1 (Berkeley) 5/29/90"
#endif /* LIBC_SCCS and not lint */
/*
* Find the first occurence of c in the memory at cp (length n).
* Return pointer to match or null pointer.
*
* This code optimises the usual case (0 < n < 65535).
*
* void *
* memchr(cp, c, n)
* char *cp, c;
* size_t n;
*/
#include "DEFS.h"
ENTRY(memchr, 0)
movq 4(ap),r1 # r1 = cp; r2 = c
movl 12(ap),r0 # r0 = n
movzwl $65535,r4 # handy constant
0:
cmpl r0,r4 # check for annoying locc limit
bgtru 3f
/* n <= 65535 */
locc r2,r0,(r1) # search n bytes for c
beql 2f # done if not found (r0 already 0)
1: /* found character c at (r1) */
movl r1,r0
2:
ret
3: /* n > 65535 */
locc r2,r4,(r1) # search 65535 bytes for c
beql 1b # done if found
decw r0 # from 0 to 65535
subl2 r0,r4 # adjust n
brb 0b # and loop
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