1992-05-13 02:52:32 +00:00
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/*-
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* Copyright (c) 1990 The Regents of the University of California.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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.asciz "@(#)memchr.s 5.1 (Berkeley) 5/29/90"
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#endif /* LIBC_SCCS and not lint */
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/*
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1996-12-20 01:35:29 +00:00
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* Find the first occurrence of c in the memory at cp (length n).
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1992-05-13 02:52:32 +00:00
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* Return pointer to match or null pointer.
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*
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* This code optimises the usual case (0 < n < 65535).
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*
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* void *
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* memchr(cp, c, n)
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* char *cp, c;
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* size_t n;
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*/
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#include "DEFS.h"
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ENTRY(memchr, 0)
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movq 4(ap),r1 # r1 = cp; r2 = c
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movl 12(ap),r0 # r0 = n
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movzwl $65535,r4 # handy constant
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0:
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cmpl r0,r4 # check for annoying locc limit
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bgtru 3f
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/* n <= 65535 */
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locc r2,r0,(r1) # search n bytes for c
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beql 2f # done if not found (r0 already 0)
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1: /* found character c at (r1) */
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movl r1,r0
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2:
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ret
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3: /* n > 65535 */
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locc r2,r4,(r1) # search 65535 bytes for c
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beql 1b # done if found
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decw r0 # from 0 to 65535
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subl2 r0,r4 # adjust n
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brb 0b # and loop
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