1 /* $NetBSD: byte_swap.h,v 1.16 2017/01/17 11:08:50 rin Exp $ */
2
3 /*-
4 * Copyright (c) 1997, 1999, 2002 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Charles M. Hannum, Neil A. Carson, and Jason R. Thorpe.
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 #ifndef _ARM_BYTE_SWAP_H_
33 #define _ARM_BYTE_SWAP_H_
34
35 #ifdef _LOCORE
36
37 #if defined(_ARM_ARCH_6) || defined(_ARM_ARCH_7)
38
39 #define BSWAP16(_src, _dst, _tmp) \
40 rev16 _dst, _src
41 #define BSWAP32(_src, _dst, _tmp) \
42 rev _dst, _src
43
44 #else
45
46 #define BSWAP16(_src, _dst, _tmp) \
47 mov _tmp, _src, ror #8 ;\
48 orr _tmp, _tmp, _tmp, lsr #16 ;\
49 bic _dst, _tmp, _tmp, lsl #16
50
51 #define BSWAP32(_src, _dst, _tmp) \
52 eor _tmp, _src, _src, ror #16 ;\
53 bic _tmp, _tmp, #0x00FF0000 ;\
54 mov _dst, _src, ror #8 ;\
55 eor _dst, _dst, _tmp, lsr #8
56
57 #endif
58
59
60 #else
61
62 #ifdef __GNUC__
63 #include <sys/types.h>
64 __BEGIN_DECLS
65
66 #define __BYTE_SWAP_U32_VARIABLE __byte_swap_u32_variable
67 static __inline uint32_t
__byte_swap_u32_variable(uint32_t v)68 __byte_swap_u32_variable(uint32_t v)
69 {
70 uint32_t t1;
71
72 #ifdef _ARM_ARCH_6
73 if (!__builtin_constant_p(v)) {
74 __asm("rev\t%0, %1" : "=r" (v) : "0" (v));
75 return v;
76 }
77 #endif
78
79 t1 = v ^ ((v << 16) | (v >> 16));
80 t1 &= 0xff00ffffU;
81 v = (v >> 8) | (v << 24);
82 v ^= (t1 >> 8);
83
84 return v;
85 }
86
87 #define __BYTE_SWAP_U16_VARIABLE __byte_swap_u16_variable
88 static __inline uint16_t
__byte_swap_u16_variable(uint16_t v)89 __byte_swap_u16_variable(uint16_t v)
90 {
91
92 #ifdef _ARM_ARCH_6
93 if (!__builtin_constant_p(v)) {
94 uint32_t v32 = v;
95 __asm("rev16\t%0, %1" : "=r" (v32) : "0" (v32));
96 return (uint16_t)v32;
97 }
98 #elif !defined(__thumb__) && 0 /* gcc produces decent code for this */
99 if (!__builtin_constant_p(v)) {
100 uint32_t v0 = v;
101 __asm volatile(
102 "mov %0, %1, ror #8\n"
103 "orr %0, %0, %0, lsr #16\n"
104 "bic %0, %0, %0, lsl #16"
105 : "=&r" (v0)
106 : "0" (v0));
107 return (uint16_t)v0;
108 }
109 #endif
110 v &= 0xffff;
111 v = (uint16_t)((v >> 8) | (v << 8));
112
113 return v;
114 }
115
116 __END_DECLS
117 #endif
118
119 #endif /* _LOCORE */
120
121 #endif /* _ARM_BYTE_SWAP_H_ */
122