86 lines
2.7 KiB
ArmAsm
86 lines
2.7 KiB
ArmAsm
/*
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* Copyright (c) 1983 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 "@(#)strncmp.s 5.6 (Berkeley) 6/1/90"
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#endif /* LIBC_SCCS and not lint */
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/*
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* Compare at most n characters of string
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* s1 lexicographically to string s2.
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* Return:
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* 0 s1 == s2
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* > 0 s1 > s2
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* < 0 s2 < s2
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*
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* strncmp(s1, s2, n)
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* char *s1, *s2;
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* int n;
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*/
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#include "DEFS.h"
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ENTRY(strncmp, 0)
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movl 4(ap),r1 # r1 = s1
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movq 8(ap),r3 # r3 = s2; r4 = n
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1:
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clrl r5 # calculate min bytes to next page boundary
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subb3 r1,$255,r5 # r5 = (bytes - 1) to end of page for s1
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subb3 r3,$255,r0 # r0 = (bytes - 1) to end of page for s2
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cmpb r0,r5 # r5 = min(r0, r5);
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bgtru 2f
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movb r0,r5
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2:
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incl r5 # r5 = min bytes to next page boundary
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cmpl r4,r5 # r5 = min(n, r5);
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bgeq 3f
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movl r4,r5
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3:
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cmpc3 r5,(r1),(r3) # compare strings
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bneq 4f
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subl2 r5,r4 # check for end of comparison
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beql 5f
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subl2 r5,r1 # check if found null yet
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locc $0,r5,(r1)
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beql 1b # not yet done, continue checking
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subl2 r0,r3
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mnegb (r3),r0 # r0 = '\0' - *s2
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cvtbl r0,r0
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ret
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4:
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subl2 r0,r5 # check for null in matching string
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subl2 r5,r1
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locc $0,r5,(r1)
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bneq 5f
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subb3 (r3),(r1),r0 # r0 = *s1 - *s2
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cvtbl r0,r0
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ret
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5:
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clrl r0 # both the same to null
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ret
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