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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#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) \
19 ((__typeof__(*(ptr)))__get_unaligned((ptr), sizeof(*(ptr))))
20#define put_unaligned(x,ptr) \
21 __put_unaligned((unsigned long)(x), (ptr), sizeof(*(ptr)))
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 */
29extern void bad_unaligned_access_length(void) __attribute__((noreturn));
30
31struct __una_u64 { __u64 x __attribute__((packed)); };
32struct __una_u32 { __u32 x __attribute__((packed)); };
33struct __una_u16 { __u16 x __attribute__((packed)); };
34
35/*
36 * Elemental unaligned loads
37 */
38
39static inline unsigned long __uldq(const __u64 *addr)
40{
41 const struct __una_u64 *ptr = (const struct __una_u64 *) addr;
42 return ptr->x;
43}
44
45static inline unsigned long __uldl(const __u32 *addr)
46{
47 const struct __una_u32 *ptr = (const struct __una_u32 *) addr;
48 return ptr->x;
49}
50
51static inline unsigned long __uldw(const __u16 *addr)
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
61static inline void __ustq(__u64 val, __u64 *addr)
62{
63 struct __una_u64 *ptr = (struct __una_u64 *) addr;
64 ptr->x = val;
65}
66
67static inline void __ustl(__u32 val, __u32 *addr)
68{
69 struct __una_u32 *ptr = (struct __una_u32 *) addr;
70 ptr->x = val;
71}
72
73static inline void __ustw(__u16 val, __u16 *addr)
74{
75 struct __una_u16 *ptr = (struct __una_u16 *) addr;
76 ptr->x = val;
77}
78
Al Viro3106dbc2005-04-24 12:28:35 -070079#define __get_unaligned(ptr, size) ({ \
80 const void *__gu_p = ptr; \
81 unsigned long val; \
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 }; \
98 val; \
99})
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100
Al Viro3106dbc2005-04-24 12:28:35 -0700101#define __put_unaligned(val, ptr, size) \
102do { \
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)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121
122#endif /* _ASM_GENERIC_UNALIGNED_H */