1/* Copyright (c) 2002, 2007 Reiner Patommel
2   Copyright (c) 2007  Dmitry Xmelkov
3   All rights reserved.
4
5   Redistribution and use in source and binary forms, with or without
6   modification, are permitted provided that the following conditions are met:
7
8   * Redistributions of source code must retain the above copyright
9     notice, this list of conditions and the following disclaimer.
10   * Redistributions in binary form must reproduce the above copyright
11     notice, this list of conditions and the following disclaimer in
12     the documentation and/or other materials provided with the
13     distribution.
14   * Neither the name of the copyright holders nor the names of
15     contributors may be used to endorse or promote products derived
16     from this software without specific prior written permission.
17
18  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
19  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
22  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28  POSSIBILITY OF SUCH DAMAGE. */
29
30/* $Id: strlwr.S 1944 2009-04-01 23:12:20Z arcanum $ */
31
32/*
33   strlwr.S
34   convert a string to lower case
35
36   Contributors:
37     Created by Reiner Patommel
38*/
39
40/** \file */
41
42/** \ingroup avr_string
43    \fn char *strlwr(char *s)
44    \brief Convert a string to lower case.
45
46    The strlwr() function will convert a string to lower case. Only the upper
47    case alphabetic characters [A .. Z] are converted.  Non-alphabetic
48    characters will not be changed.
49
50    \returns The strlwr() function returns a pointer to the converted
51    string. */
52
53#if !defined(__DOXYGEN__)
54
55#include "macros.inc"
56
57#define str_hi r25
58#define str_lo r24
59#define temp   r22
60
61	ASSEMBLY_CLIB_SECTION
62	.global	_U(strlwr)
63	.type	_U(strlwr), @function
64
65_U(strlwr):
66	X_movw	XL, str_lo
67
681:	ld	temp, X
69	subi	temp, 'A'
70	cpi	temp, 'Z'-'A'+1
71	brlo	2f		; if tepm is A..Z, then temp += 'a'-'A'
72	subi	temp, 'a'-'A'	; else restore temp
732:	subi	temp, -'a'
74	st	X+, temp
75	brne	1b		; Z for temp
76	ret
77
78	.size	_U(strlwr), . - _U(strlwr)
79
80#endif /* not __DOXYGEN__ */
81