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      1 /*	$NetBSD: strncpy.S,v 1.5 2013/09/07 19:06:29 chs Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1990 The Regents of the University of California.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to Berkeley by
      8  * the Systems Programming Group of the University of Utah Computer
      9  * Science Department.
     10  *
     11  * Redistribution and use in source and binary forms, with or without
     12  * modification, are permitted provided that the following conditions
     13  * are met:
     14  * 1. Redistributions of source code must retain the above copyright
     15  *    notice, this list of conditions and the following disclaimer.
     16  * 2. Redistributions in binary form must reproduce the above copyright
     17  *    notice, this list of conditions and the following disclaimer in the
     18  *    documentation and/or other materials provided with the distribution.
     19  * 3. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <machine/asm.h>
     37 
     38 #if defined(LIBC_SCCS) && !defined(lint)
     39 #if 0
     40 	RCSID("from: @(#)strncpy.s	5.1 (Berkeley) 5/12/90")
     41 #else
     42 	RCSID("$NetBSD: strncpy.S,v 1.5 2013/09/07 19:06:29 chs Exp $")
     43 #endif
     44 #endif /* LIBC_SCCS and not lint */
     45 
     46 ENTRY(strncpy)
     47 	movl	4(%sp),%d0		| return value is toaddr
     48 	movl	12(%sp),%d1		| count
     49 	jeq	.Lscdone		| nothing to do
     50 	movl	8(%sp),%a0		| a0 = fromaddr
     51 	movl	%d0,%a1			| a1 = toaddr
     52 	subql	#1,%d1
     53 .Lscloop:
     54 	movb	(%a0)+,(%a1)+		| copy a byte
     55 #ifndef __mcoldfire__
     56 	dbeq	%d1,.Lscloop		| loop through low word of d1
     57 #endif
     58 	jeq	.Lscpadding		| copied null, padding if necessary
     59 #ifndef __mcoldfire__
     60 	clrw	%d1			| clear low word of d1
     61 #endif
     62 	subql	#1,%d1			| adjust count for long copies
     63 	jcc	.Lscloop		| more room, keep going
     64 .Lscdone:
     65 #ifdef __SVR4_ABI__
     66 	moveal	%d0,%a0
     67 #endif
     68 	rts
     69 
     70 .Lscploop:
     71 	clrb	(%a1)+			| clear a byte
     72 #ifndef __mcoldfire__
     73 	dbra	%d1,.Lscploop		| keep going
     74 	clrw	%d1
     75 #endif
     76 .Lscpadding:
     77 	subql	#1,%d1
     78 	jcc	.Lscploop
     79 	jra	.Lscdone
     80 END(strncpy)
     81