projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 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 */ |