70 lines
2.3 KiB
ArmAsm
70 lines
2.3 KiB
ArmAsm
/* $NetBSD: memcmp.S,v 1.1 1996/05/19 15:57:44 ragge Exp $ */
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/*-
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* Copyright (c) 1990, 1993
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* The Regents of the University of California. 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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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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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/* int memcmp(s1, s2, n) */
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#include "DEFS.h"
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ENTRY(memcmp, 0)
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movl 12(ap),r0
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jeql 9f
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movq 4(ap),r1
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ashl $-2,r0,r3 # convert len to long words
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jeql 2f
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1:
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cmpl (r1)+,(r2)+ # no "cmpq" alas
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jneq 7f
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sobgtr r3,1b
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2:
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bicl3 $-4,r0,r3 # handle at most 3 extra bytes
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jeql 4f
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3:
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cmpb (r1)+,(r2)+
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jneq 8f
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sobgtr r3,3b
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4:
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clrl r0 # we had a match
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ret
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7: # backup, and do a byte compare
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tstl -(r1)
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tstl -(r2)
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movl $4,r3
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jbr 3b
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8:
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movzbl -(r1),r3
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movzbl -(r2),r4
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subl3 r4,r3,r0
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9:
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ret
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