1 /* ----------------------------------------------------------------------- *
2 *
3 * Copyright 2001-2008 H. Peter Anvin - All Rights Reserved
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation, Inc., 675 Mass Ave, Cambridge MA 02139,
8 * USA; either version 2 of the License, or (at your option) any later
9 * version; incorporated herein by reference.
10 *
11 * ----------------------------------------------------------------------- */
12
13 /*
14 * ulint.h
15 *
16 * Basic operations on unaligned, littleendian integers
17 */
18
19 #ifndef ULINT_H
20 #define ULINT_H
21
22 #include <inttypes.h>
23
24 /* These are unaligned, littleendian integer types */
25
26 typedef uint8_t le8_t; /* 8-bit byte */
27 typedef uint8_t le16_t[2]; /* 16-bit word */
28 typedef uint8_t le32_t[4]; /* 32-bit dword */
29
30 /* Read/write these quantities */
31
read8(le8_t * _p)32 static inline unsigned char read8(le8_t * _p)
33 {
34 return *_p;
35 }
36
write8(le8_t * _p,uint8_t _v)37 static inline void write8(le8_t * _p, uint8_t _v)
38 {
39 *_p = _v;
40 }
41
42 #if defined(__i386__) || defined(__x86_64__)
43
44 /* Littleendian architectures which support unaligned memory accesses */
45
read16(le16_t * _p)46 static inline unsigned short read16(le16_t * _p)
47 {
48 return *((const uint16_t *)_p);
49 }
50
write16(le16_t * _p,unsigned short _v)51 static inline void write16(le16_t * _p, unsigned short _v)
52 {
53 *((uint16_t *) _p) = _v;
54 }
55
read32(le32_t * _p)56 static inline unsigned int read32(le32_t * _p)
57 {
58 return *((const uint32_t *)_p);
59 }
60
write32(le32_t * _p,uint32_t _v)61 static inline void write32(le32_t * _p, uint32_t _v)
62 {
63 *((uint32_t *) _p) = _v;
64 }
65
66 #else
67
68 /* Generic, mostly portable versions */
69
read16(le16_t * _pp)70 static inline unsigned short read16(le16_t * _pp)
71 {
72 uint8_t *_p = *_pp;
73 uint16_t _v;
74
75 _v = _p[0];
76 _v |= _p[1] << 8;
77 return _v;
78 }
79
write16(le16_t * _pp,uint16_t _v)80 static inline void write16(le16_t * _pp, uint16_t _v)
81 {
82 uint8_t *_p = *_pp;
83
84 _p[0] = _v & 0xFF;
85 _p[1] = (_v >> 8) & 0xFF;
86 }
87
read32(le32_t * _pp)88 static inline unsigned int read32(le32_t * _pp)
89 {
90 uint8_t *_p = *_pp;
91 uint32_t _v;
92
93 _v = _p[0];
94 _v |= _p[1] << 8;
95 _v |= _p[2] << 16;
96 _v |= _p[3] << 24;
97 return _v;
98 }
99
write32(le32_t * _pp,uint32_t _v)100 static inline void write32(le32_t * _pp, uint32_t _v)
101 {
102 uint8_t *_p = *_pp;
103
104 _p[0] = _v & 0xFF;
105 _p[1] = (_v >> 8) & 0xFF;
106 _p[2] = (_v >> 16) & 0xFF;
107 _p[3] = (_v >> 24) & 0xFF;
108 }
109
110 #endif
111
112 #endif /* ULINT_H */
113