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/*
* Copyright (c) 1983 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.
* 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 "@(#)strncpy.s 5.6 (Berkeley) 6/1/90"
#endif /* LIBC_SCCS and not lint */
/*
* Copy string s2 over top of string s1.
* Truncate or null-pad to n bytes.
*
* char *
* strncpy(s1, s2, n)
* char *s1, *s2;
*/
#include "DEFS.h"
ENTRY(strncpy, R6)
movl 12(ap),r6 # r6 = n
bleq done # n <= 0
movl 4(ap),r3 # r3 = s1
movl 8(ap),r1 # r1 = s2
1:
movzwl $65535,r2 # r2 = bytes in first chunk
cmpl r6,r2 # r2 = min(bytes in chunk, n);
jgeq 2f
movl r6,r2
2:
subl2 r2,r6 # update n
locc $0,r2,(r1) # '\0' found?
jneq 3f
subl2 r2,r1 # back up pointer updated by locc
movc3 r2,(r1),(r3) # copy in next piece
tstl r6 # run out of space?
jneq 1b
jbr done
3: # copy up to '\0' logic
addl2 r0,r6 # r6 = number of null-pad bytes
subl2 r0,r2 # r2 = number of bytes to move
subl2 r2,r1 # back up pointer updated by locc
movc3 r2,(r1),(r3) # copy in last piece
4: # null-pad logic
movzwl $65535,r2 # r2 = bytes in first chunk
cmpl r6,r2 # r2 = min(bytes in chunk, n);
jgeq 5f
movl r6,r2
5:
subl2 r2,r6 # update n
movc5 $0,(r3),$0,r2,(r3)# pad with '\0's
tstl r6 # finished padding?
jneq 4b
done:
movl 4(ap),r0 # return s1
ret
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