1/*	$NetBSD: strlcpy.S,v 1.5 2020/05/05 06:20:55 skrll Exp $	*/
2
3/*
4 * Copyright (c) 2002 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Matthew Fredette.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#include <machine/asm.h>
33
34#if defined(LIBC_SCCS) && !defined(lint)
35        RCSID("$NetBSD: strlcpy.S,v 1.5 2020/05/05 06:20:55 skrll Exp $")
36#endif /* LIBC_SCCS and not lint */
37
38/*
39 * size_t strlcpy(char *dst, const char *src, size_t size);
40 */
41LEAF_ENTRY(_strlcpy)
42	.weak strlcpy
43	strlcpy = _strlcpy
44
45	/* Always load the first byte of the source string. */
46	ldbs,ma		1(%arg1), %r1
47
48	/*
49	 * If our dst buffer is zero bytes, branch immediately
50	 * to the code that counts the (remaining) length
51	 * of the src string.
52	 */
53	comb,=		%r0, %arg2, $strlcpy_dst_done
54	 copy		%arg1, %ret0
55
56	/*
57	 * If our dst buffer is one byte, branch immediately
58	 * to the code that NUL-terminates the dst buffer and
59	 * counts the (remaining) length of the src string.
60	 */
61	addib,=,n	-1, %arg2, $strlcpy_dst_full
62
63	/*
64	 * Loop copying bytes.  At the top of this loop,
65	 * %arg2 is always the number of bytes we can still
66	 * store, and %r1 holds the next byte to store.
67	 */
68$strlcpy_loop:
69	comb,=		%r0, %r1, $strlcpy_exit
70	 stbs,ma	%r1, 1(%arg0)
71	addib,<>	-1, %arg2, $strlcpy_loop
72	 ldbs,ma	1(%arg1), %r1
73
74$strlcpy_dst_full:
75	stbs,ma		%r0, 1(%arg0)
76
77$strlcpy_dst_done:
78	comb,<>,n	%r0, %r1, $strlcpy_dst_done
79	ldbs,ma		1(%arg1), %r1
80
81$strlcpy_exit:
82	bv		%r0(%rp)
83	 sub		%arg1, %ret0, %ret0
84EXIT(strlcpy)
85