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, long * addr)
46 {
47 int mask;
48
49 addr += nr >> 5;
50 mask = 1 << (nr & 0x1f);
51 return ((mask & *addr) != 0);
52 }
53
54 #ifdef __KERNEL__
55
56 /*
57 * ffs: find first bit set. This is defined the same way as
58 * the libc and compiler builtin ffs routines, therefore
59 * differs in spirit from the above ffz (man ffs).
60 */
61
62 #define ffs(x) generic_ffs(x)
63
64 /*
65 * hweightN: returns the hamming weight (i.e. the number
66 * of bits set) of a N-bit word
67 */
68
69 #define hweight32(x) generic_hweight32(x)
70 #define hweight16(x) generic_hweight16(x)
71 #define hweight8(x) generic_hweight8(x)
72
73 #endif /* __KERNEL__ */
74
75 #endif /* _ASM_GENERIC_BITOPS_H */
76
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