diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/asm-v850/unaligned.h |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'include/asm-v850/unaligned.h')
-rw-r--r-- | include/asm-v850/unaligned.h | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/include/asm-v850/unaligned.h b/include/asm-v850/unaligned.h new file mode 100644 index 000000000000..65e38362142b --- /dev/null +++ b/include/asm-v850/unaligned.h | |||
@@ -0,0 +1,130 @@ | |||
1 | /* | ||
2 | * include/asm-v850/unaligned.h -- Unaligned memory access | ||
3 | * | ||
4 | * Copyright (C) 2001 NEC Corporation | ||
5 | * Copyright (C) 2001 Miles Bader <miles@gnu.org> | ||
6 | * | ||
7 | * This file is subject to the terms and conditions of the GNU General | ||
8 | * Public License. See the file COPYING in the main directory of this | ||
9 | * archive for more details. | ||
10 | * | ||
11 | * This file is a copy of the arm version, include/asm-arm/unaligned.h | ||
12 | * | ||
13 | * Note that some v850 chips support unaligned access, but it seems too | ||
14 | * annoying to use. | ||
15 | */ | ||
16 | |||
17 | #ifndef __V850_UNALIGNED_H__ | ||
18 | #define __V850_UNALIGNED_H__ | ||
19 | |||
20 | #include <asm/types.h> | ||
21 | |||
22 | extern int __bug_unaligned_x(void *ptr); | ||
23 | |||
24 | /* | ||
25 | * What is the most efficient way of loading/storing an unaligned value? | ||
26 | * | ||
27 | * That is the subject of this file. Efficiency here is defined as | ||
28 | * minimum code size with minimum register usage for the common cases. | ||
29 | * It is currently not believed that long longs are common, so we | ||
30 | * trade efficiency for the chars, shorts and longs against the long | ||
31 | * longs. | ||
32 | * | ||
33 | * Current stats with gcc 2.7.2.2 for these functions: | ||
34 | * | ||
35 | * ptrsize get: code regs put: code regs | ||
36 | * 1 1 1 1 2 | ||
37 | * 2 3 2 3 2 | ||
38 | * 4 7 3 7 3 | ||
39 | * 8 20 6 16 6 | ||
40 | * | ||
41 | * gcc 2.95.1 seems to code differently: | ||
42 | * | ||
43 | * ptrsize get: code regs put: code regs | ||
44 | * 1 1 1 1 2 | ||
45 | * 2 3 2 3 2 | ||
46 | * 4 7 4 7 4 | ||
47 | * 8 19 8 15 6 | ||
48 | * | ||
49 | * which may or may not be more efficient (depending upon whether | ||
50 | * you can afford the extra registers). Hopefully the gcc 2.95 | ||
51 | * is inteligent enough to decide if it is better to use the | ||
52 | * extra register, but evidence so far seems to suggest otherwise. | ||
53 | * | ||
54 | * Unfortunately, gcc is not able to optimise the high word | ||
55 | * out of long long >> 32, or the low word from long long << 32 | ||
56 | */ | ||
57 | |||
58 | #define __get_unaligned_2(__p) \ | ||
59 | (__p[0] | __p[1] << 8) | ||
60 | |||
61 | #define __get_unaligned_4(__p) \ | ||
62 | (__p[0] | __p[1] << 8 | __p[2] << 16 | __p[3] << 24) | ||
63 | |||
64 | #define get_unaligned(ptr) \ | ||
65 | ({ \ | ||
66 | __typeof__(*(ptr)) __v; \ | ||
67 | __u8 *__p = (__u8 *)(ptr); \ | ||
68 | switch (sizeof(*(ptr))) { \ | ||
69 | case 1: __v = *(ptr); break; \ | ||
70 | case 2: __v = __get_unaligned_2(__p); break; \ | ||
71 | case 4: __v = __get_unaligned_4(__p); break; \ | ||
72 | case 8: { \ | ||
73 | unsigned int __v1, __v2; \ | ||
74 | __v2 = __get_unaligned_4((__p+4)); \ | ||
75 | __v1 = __get_unaligned_4(__p); \ | ||
76 | __v = ((unsigned long long)__v2 << 32 | __v1); \ | ||
77 | } \ | ||
78 | break; \ | ||
79 | default: __v = __bug_unaligned_x(__p); break; \ | ||
80 | } \ | ||
81 | __v; \ | ||
82 | }) | ||
83 | |||
84 | |||
85 | extern inline void __put_unaligned_2(__u32 __v, register __u8 *__p) | ||
86 | { | ||
87 | *__p++ = __v; | ||
88 | *__p++ = __v >> 8; | ||
89 | } | ||
90 | |||
91 | extern inline void __put_unaligned_4(__u32 __v, register __u8 *__p) | ||
92 | { | ||
93 | __put_unaligned_2(__v >> 16, __p + 2); | ||
94 | __put_unaligned_2(__v, __p); | ||
95 | } | ||
96 | |||
97 | extern inline void __put_unaligned_8(const unsigned long long __v, register __u8 *__p) | ||
98 | { | ||
99 | /* | ||
100 | * tradeoff: 8 bytes of stack for all unaligned puts (2 | ||
101 | * instructions), or an extra register in the long long | ||
102 | * case - go for the extra register. | ||
103 | */ | ||
104 | __put_unaligned_4(__v >> 32, __p+4); | ||
105 | __put_unaligned_4(__v, __p); | ||
106 | } | ||
107 | |||
108 | /* | ||
109 | * Try to store an unaligned value as efficiently as possible. | ||
110 | */ | ||
111 | #define put_unaligned(val,ptr) \ | ||
112 | ({ \ | ||
113 | switch (sizeof(*(ptr))) { \ | ||
114 | case 1: \ | ||
115 | *(ptr) = (val); \ | ||
116 | break; \ | ||
117 | case 2: __put_unaligned_2((val),(__u8 *)(ptr)); \ | ||
118 | break; \ | ||
119 | case 4: __put_unaligned_4((val),(__u8 *)(ptr)); \ | ||
120 | break; \ | ||
121 | case 8: __put_unaligned_8((val),(__u8 *)(ptr)); \ | ||
122 | break; \ | ||
123 | default: __bug_unaligned_x(ptr); \ | ||
124 | break; \ | ||
125 | } \ | ||
126 | (void) 0; \ | ||
127 | }) | ||
128 | |||
129 | |||
130 | #endif /* __V850_UNALIGNED_H__ */ | ||