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1da177e4 LT |
1 | #ifndef _ASM_GENERIC_BITOPS_H_ |
2 | #define _ASM_GENERIC_BITOPS_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. You should | |
7 | * recode these in the native assembly language, if at all possible. | |
8 | * To guarantee atomicity, these routines call cli() and sti() to | |
9 | * disable interrupts while they operate. (You have to provide inline | |
10 | * routines to cli() and sti().) | |
11 | * | |
12 | * Also note, these routines assume that you have 32 bit longs. | |
13 | * You will have to change this if you are trying to port Linux to the | |
14 | * Alpha architecture or to a Cray. :-) | |
15 | * | |
16 | * C language equivalents written by Theodore Ts'o, 9/26/92 | |
17 | */ | |
18 | ||
19 | extern __inline__ int set_bit(int nr,long * addr) | |
20 | { | |
21 | int mask, retval; | |
22 | ||
23 | addr += nr >> 5; | |
24 | mask = 1 << (nr & 0x1f); | |
25 | cli(); | |
26 | retval = (mask & *addr) != 0; | |
27 | *addr |= mask; | |
28 | sti(); | |
29 | return retval; | |
30 | } | |
31 | ||
32 | extern __inline__ int clear_bit(int nr, long * addr) | |
33 | { | |
34 | int mask, retval; | |
35 | ||
36 | addr += nr >> 5; | |
37 | mask = 1 << (nr & 0x1f); | |
38 | cli(); | |
39 | retval = (mask & *addr) != 0; | |
40 | *addr &= ~mask; | |
41 | sti(); | |
42 | return retval; | |
43 | } | |
44 | ||
45 | extern __inline__ int test_bit(int nr, const unsigned long * addr) | |
46 | { | |
47 | int mask; | |
48 | ||
49 | addr += nr >> 5; | |
50 | mask = 1 << (nr & 0x1f); | |
51 | return ((mask & *addr) != 0); | |
52 | } | |
53 | ||
54 | /* | |
55 | * fls: find last bit set. | |
56 | */ | |
57 | ||
58 | #define fls(x) generic_fls(x) | |
59 | ||
60 | #ifdef __KERNEL__ | |
61 | ||
62 | /* | |
63 | * ffs: find first bit set. This is defined the same way as | |
64 | * the libc and compiler builtin ffs routines, therefore | |
65 | * differs in spirit from the above ffz (man ffs). | |
66 | */ | |
67 | ||
68 | #define ffs(x) generic_ffs(x) | |
69 | ||
70 | /* | |
71 | * hweightN: returns the hamming weight (i.e. the number | |
72 | * of bits set) of a N-bit word | |
73 | */ | |
74 | ||
75 | #define hweight32(x) generic_hweight32(x) | |
76 | #define hweight16(x) generic_hweight16(x) | |
77 | #define hweight8(x) generic_hweight8(x) | |
78 | ||
79 | #endif /* __KERNEL__ */ | |
80 | ||
81 | #endif /* _ASM_GENERIC_BITOPS_H */ |