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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 422 | giacomo | 1 | #ifndef _ASM_GENERIC_BITOPS_H_ |
| 2 | #define _ASM_GENERIC_BITOPS_H_ |
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| 3 | |||
| 4 | /* |
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| 5 | * For the benefit of those who are trying to port Linux to another |
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| 6 | * architecture, here are some C-language equivalents. You should |
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| 7 | * recode these in the native assembly language, if at all possible. |
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| 8 | * To guarantee atomicity, these routines call cli() and sti() to |
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| 9 | * disable interrupts while they operate. (You have to provide inline |
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| 10 | * routines to cli() and sti().) |
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| 11 | * |
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| 12 | * Also note, these routines assume that you have 32 bit longs. |
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| 13 | * You will have to change this if you are trying to port Linux to the |
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| 14 | * Alpha architecture or to a Cray. :-) |
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| 15 | * |
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| 16 | * C language equivalents written by Theodore Ts'o, 9/26/92 |
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| 17 | */ |
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| 18 | |||
| 19 | extern __inline__ int set_bit(int nr,long * addr) |
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| 20 | { |
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| 21 | int mask, retval; |
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| 22 | |||
| 23 | addr += nr >> 5; |
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| 24 | mask = 1 << (nr & 0x1f); |
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| 25 | cli(); |
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| 26 | retval = (mask & *addr) != 0; |
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| 27 | *addr |= mask; |
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| 28 | sti(); |
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| 29 | return retval; |
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| 30 | } |
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| 31 | |||
| 32 | extern __inline__ int clear_bit(int nr, long * addr) |
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| 33 | { |
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| 34 | int mask, retval; |
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| 35 | |||
| 36 | addr += nr >> 5; |
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| 37 | mask = 1 << (nr & 0x1f); |
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| 38 | cli(); |
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| 39 | retval = (mask & *addr) != 0; |
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| 40 | *addr &= ~mask; |
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| 41 | sti(); |
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| 42 | return retval; |
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| 43 | } |
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| 44 | |||
| 45 | extern __inline__ int test_bit(int nr, long * addr) |
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| 46 | { |
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| 47 | int mask; |
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| 48 | |||
| 49 | addr += nr >> 5; |
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| 50 | mask = 1 << (nr & 0x1f); |
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| 51 | return ((mask & *addr) != 0); |
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| 52 | } |
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| 53 | |||
| 54 | /* |
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| 55 | * fls: find last bit set. |
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| 56 | */ |
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| 57 | |||
| 58 | #define fls(x) generic_fls(x) |
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| 59 | |||
| 60 | #ifdef __KERNEL__ |
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| 61 | |||
| 62 | /* |
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| 63 | * ffs: find first bit set. This is defined the same way as |
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| 64 | * the libc and compiler builtin ffs routines, therefore |
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| 65 | * differs in spirit from the above ffz (man ffs). |
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| 66 | */ |
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| 67 | |||
| 68 | #define ffs(x) generic_ffs(x) |
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| 69 | |||
| 70 | /* |
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| 71 | * hweightN: returns the hamming weight (i.e. the number |
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| 72 | * of bits set) of a N-bit word |
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| 73 | */ |
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| 74 | |||
| 75 | #define hweight32(x) generic_hweight32(x) |
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| 76 | #define hweight16(x) generic_hweight16(x) |
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| 77 | #define hweight8(x) generic_hweight8(x) |
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| 78 | |||
| 79 | #endif /* __KERNEL__ */ |
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| 80 | |||
| 81 | #endif /* _ASM_GENERIC_BITOPS_H */ |