| #ifndef _ASM_GENERIC_BITOPS_H_ |
| #define _ASM_GENERIC_BITOPS_H_ |
| |
| /* |
| * For the benefit of those who are trying to port Linux to another |
| * architecture, here are some C-language equivalents. You should |
| * recode these in the native assembly language, if at all possible. |
| * To guarantee atomicity, these routines call cli() and sti() to |
| * disable interrupts while they operate. (You have to provide inline |
| * routines to cli() and sti().) |
| * |
| * Also note, these routines assume that you have 32 bit longs. |
| * You will have to change this if you are trying to port Linux to the |
| * Alpha architecture or to a Cray. :-) |
| * |
| * C language equivalents written by Theodore Ts'o, 9/26/92 |
| */ |
| |
| extern __inline__ int set_bit(int nr,long * addr) |
| { |
| int mask, retval; |
| |
| addr += nr >> 5; |
| mask = 1 << (nr & 0x1f); |
| cli(); |
| retval = (mask & *addr) != 0; |
| *addr |= mask; |
| sti(); |
| return retval; |
| } |
| |
| extern __inline__ int clear_bit(int nr, long * addr) |
| { |
| int mask, retval; |
| |
| addr += nr >> 5; |
| mask = 1 << (nr & 0x1f); |
| cli(); |
| retval = (mask & *addr) != 0; |
| *addr &= ~mask; |
| sti(); |
| return retval; |
| } |
| |
| extern __inline__ int test_bit(int nr, long * addr) |
| { |
| int mask; |
| |
| addr += nr >> 5; |
| mask = 1 << (nr & 0x1f); |
| return ((mask & *addr) != 0); |
| } |
| |
| #ifdef __KERNEL__ |
| |
| /* |
| * ffs: find first bit set. This is defined the same way as |
| * the libc and compiler builtin ffs routines, therefore |
| * differs in spirit from the above ffz (man ffs). |
| */ |
| |
| #define ffs(x) generic_ffs(x) |
| |
| /* |
| * hweightN: returns the hamming weight (i.e. the number |
| * of bits set) of a N-bit word |
| */ |
| |
| #define hweight32(x) generic_hweight32(x) |
| #define hweight16(x) generic_hweight16(x) |
| #define hweight8(x) generic_hweight8(x) |
| |
| #endif /* __KERNEL__ */ |
| |
| #endif /* _ASM_GENERIC_BITOPS_H */ |