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1da177e4 LT |
1 | #ifndef _ASM_GENERIC_UNALIGNED_H_ |
2 | #define _ASM_GENERIC_UNALIGNED_H_ | |
3 | ||
4 | /* | |
5 | * For the benefit of those who are trying to port Linux to another | |
6 | * architecture, here are some C-language equivalents. | |
7 | * | |
8 | * This is based almost entirely upon Richard Henderson's | |
9 | * asm-alpha/unaligned.h implementation. Some comments were | |
10 | * taken from David Mosberger's asm-ia64/unaligned.h header. | |
11 | */ | |
12 | ||
13 | #include <linux/types.h> | |
14 | ||
15 | /* | |
16 | * The main single-value unaligned transfer routines. | |
17 | */ | |
18 | #define get_unaligned(ptr) \ | |
eed74dfc | 19 | __get_unaligned((ptr), sizeof(*(ptr))) |
1da177e4 | 20 | #define put_unaligned(x,ptr) \ |
eed74dfc | 21 | __put_unaligned((__u64)(x), (ptr), sizeof(*(ptr))) |
1da177e4 LT |
22 | |
23 | /* | |
24 | * This function doesn't actually exist. The idea is that when | |
25 | * someone uses the macros below with an unsupported size (datatype), | |
26 | * the linker will alert us to the problem via an unresolved reference | |
27 | * error. | |
28 | */ | |
29 | extern void bad_unaligned_access_length(void) __attribute__((noreturn)); | |
30 | ||
31 | struct __una_u64 { __u64 x __attribute__((packed)); }; | |
32 | struct __una_u32 { __u32 x __attribute__((packed)); }; | |
33 | struct __una_u16 { __u16 x __attribute__((packed)); }; | |
34 | ||
35 | /* | |
36 | * Elemental unaligned loads | |
37 | */ | |
38 | ||
eed74dfc | 39 | static inline __u64 __uldq(const __u64 *addr) |
1da177e4 LT |
40 | { |
41 | const struct __una_u64 *ptr = (const struct __una_u64 *) addr; | |
42 | return ptr->x; | |
43 | } | |
44 | ||
eed74dfc | 45 | static inline __u32 __uldl(const __u32 *addr) |
1da177e4 LT |
46 | { |
47 | const struct __una_u32 *ptr = (const struct __una_u32 *) addr; | |
48 | return ptr->x; | |
49 | } | |
50 | ||
eed74dfc | 51 | static inline __u16 __uldw(const __u16 *addr) |
1da177e4 LT |
52 | { |
53 | const struct __una_u16 *ptr = (const struct __una_u16 *) addr; | |
54 | return ptr->x; | |
55 | } | |
56 | ||
57 | /* | |
58 | * Elemental unaligned stores | |
59 | */ | |
60 | ||
61 | static inline void __ustq(__u64 val, __u64 *addr) | |
62 | { | |
63 | struct __una_u64 *ptr = (struct __una_u64 *) addr; | |
64 | ptr->x = val; | |
65 | } | |
66 | ||
67 | static inline void __ustl(__u32 val, __u32 *addr) | |
68 | { | |
69 | struct __una_u32 *ptr = (struct __una_u32 *) addr; | |
70 | ptr->x = val; | |
71 | } | |
72 | ||
73 | static inline void __ustw(__u16 val, __u16 *addr) | |
74 | { | |
75 | struct __una_u16 *ptr = (struct __una_u16 *) addr; | |
76 | ptr->x = val; | |
77 | } | |
78 | ||
3106dbcd AV |
79 | #define __get_unaligned(ptr, size) ({ \ |
80 | const void *__gu_p = ptr; \ | |
707ced0d | 81 | __u64 val; \ |
3106dbcd AV |
82 | switch (size) { \ |
83 | case 1: \ | |
84 | val = *(const __u8 *)__gu_p; \ | |
85 | break; \ | |
86 | case 2: \ | |
87 | val = __uldw(__gu_p); \ | |
88 | break; \ | |
89 | case 4: \ | |
90 | val = __uldl(__gu_p); \ | |
91 | break; \ | |
92 | case 8: \ | |
93 | val = __uldq(__gu_p); \ | |
94 | break; \ | |
95 | default: \ | |
96 | bad_unaligned_access_length(); \ | |
97 | }; \ | |
707ced0d | 98 | (__typeof__(*(ptr)))val; \ |
3106dbcd AV |
99 | }) |
100 | ||
101 | #define __put_unaligned(val, ptr, size) \ | |
102 | do { \ | |
103 | void *__gu_p = ptr; \ | |
104 | switch (size) { \ | |
105 | case 1: \ | |
106 | *(__u8 *)__gu_p = val; \ | |
107 | break; \ | |
108 | case 2: \ | |
109 | __ustw(val, __gu_p); \ | |
110 | break; \ | |
111 | case 4: \ | |
112 | __ustl(val, __gu_p); \ | |
113 | break; \ | |
114 | case 8: \ | |
115 | __ustq(val, __gu_p); \ | |
116 | break; \ | |
117 | default: \ | |
118 | bad_unaligned_access_length(); \ | |
119 | }; \ | |
120 | } while(0) | |
1da177e4 LT |
121 | |
122 | #endif /* _ASM_GENERIC_UNALIGNED_H */ |