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      1  1.1  matt /*-
      2  1.1  matt  * Copyright (c) 2013 The NetBSD Foundation, Inc.
      3  1.1  matt  * All rights reserved.
      4  1.1  matt  *
      5  1.1  matt  * This code is derived from software contributed to The NetBSD Foundation
      6  1.1  matt  * by Matt Thomas of 3am Software Foundry.
      7  1.1  matt  *
      8  1.1  matt  * Redistribution and use in source and binary forms, with or without
      9  1.1  matt  * modification, are permitted provided that the following conditions
     10  1.1  matt  * are met:
     11  1.1  matt  * 1. Redistributions of source code must retain the above copyright
     12  1.1  matt  *    notice, this list of conditions and the following disclaimer.
     13  1.1  matt  * 2. Redistributions in binary form must reproduce the above copyright
     14  1.1  matt  *    notice, this list of conditions and the following disclaimer in the
     15  1.1  matt  *    documentation and/or other materials provided with the distribution.
     16  1.1  matt  *
     17  1.1  matt  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     18  1.1  matt  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     19  1.1  matt  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     20  1.1  matt  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     21  1.1  matt  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     22  1.1  matt  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     23  1.1  matt  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     24  1.1  matt  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     25  1.1  matt  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     26  1.1  matt  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     27  1.1  matt  * POSSIBILITY OF SUCH DAMAGE.
     28  1.1  matt  */
     29  1.1  matt 
     30  1.1  matt #include <machine/asm.h>
     31  1.1  matt 
     32  1.3  matt RCSID("$NetBSD: strcat_naive.S,v 1.3 2013/08/19 17:02:25 matt Exp $")
     33  1.1  matt 
     34  1.1  matt ENTRY(strcat)
     35  1.1  matt 	mov	ip, r0			/* need to preserve r0 */
     36  1.2  matt #if defined(__thumb__)
     37  1.2  matt 1:	ldrb	r2, [r0]		/* load next byte */
     38  1.2  matt 	adds	r0, r0, #1		/* advance */
     39  1.2  matt 	cmp	r2, #0			/* was it a NUL? */
     40  1.2  matt 	bne	1b			/*   no, get next byte */
     41  1.2  matt 	subs	r0, r0, #1		/* back up one to the NUL */
     42  1.2  matt 	subs	r1, r1, r0		/* save one increment */
     43  1.2  matt 2:	ldrb	r2, [r1, r0]		/* load next byte from append */
     44  1.2  matt 	strb	r2, [r0]		/* store it */
     45  1.2  matt 	adds	r0, r0, #1		/* advance */
     46  1.2  matt 	cmp	r2, #0			/* was it a NUL? */
     47  1.2  matt 	bne	2b			/*   no, get next byte */
     48  1.2  matt 	mov	r0, ip			/* restore dst address */
     49  1.2  matt 	RET				/* return */
     50  1.2  matt #else /* !__thumb__ */
     51  1.2  matt 	mov	ip, r0			/* need to preserve r0 */
     52  1.1  matt 1:	ldrb	r2, [ip], #1		/* load next byte */
     53  1.1  matt 	teq	r2, #0			/* was it a NUL? */
     54  1.1  matt 	bne	1b			/*   no, get next byte */
     55  1.1  matt 	sub	ip, ip, #1		/* back up one to the NUL */
     56  1.1  matt 2:	ldrb	r2, [r1], #1		/* load next byte from append */
     57  1.1  matt 	strb	r2, [ip], #1		/* store it */
     58  1.1  matt 	teq	r2, #0			/* was it a NUL? */
     59  1.1  matt 	bne	2b			/*   no, get next byte */
     60  1.1  matt 	RET				/* return */
     61  1.2  matt #endif
     62  1.1  matt END(strcat)
     63