#ifndef _LINUX_BITOPS_H #define _LINUX_BITOPS_H #include #define BITS_PER_LONG 32 /** * fls - find last (most-significant) bit set * @x: the word to search * * This is defined the same way as ffs. * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32. */ static inline int generic_fls(int x) { int r = 32; if (!x) return 0; if (!(x & 0xffff0000u)) { x <<= 16; r -= 16; } if (!(x & 0xff000000u)) { x <<= 8; r -= 8; } if (!(x & 0xf0000000u)) { x <<= 4; r -= 4; } if (!(x & 0xc0000000u)) { x <<= 2; r -= 2; } if (!(x & 0x80000000u)) { x <<= 1; r -= 1; } return r; } /** * ffs - find first bit set * @x: the word to search * * This is defined the same way as * the libc and compiler builtin ffs routines, therefore * differs in spirit from the above ffz (man ffs). */ static inline int generic_ffs(int x) { int r = 1; if (!x) return 0; if (!(x & 0xffff)) { x >>= 16; r += 16; } if (!(x & 0xff)) { x >>= 8; r += 8; } if (!(x & 0xf)) { x >>= 4; r += 4; } if (!(x & 3)) { x >>= 2; r += 2; } if (!(x & 1)) { x >>= 1; r += 1; } return r; } #define BIT_MASK(nr) (1UL << ((nr) % BITS_PER_LONG)) #define BIT_WORD(nr) ((nr) / BITS_PER_LONG) /* linux/include/asm-generic/bitops/non-atomic.h */ #ifndef PLATFORM__SET_BIT # define __set_bit generic_set_bit #endif #ifndef PLATFORM__CLEAR_BIT # define __clear_bit generic_clear_bit #endif #ifndef PLATFORM_FFS # define ffs generic_ffs #endif #ifndef PLATFORM_FLS # define fls generic_fls #endif /** * __set_bit - Set a bit in memory * @nr: the bit to set * @addr: the address to start counting from * * Unlike set_bit(), this function is non-atomic and may be reordered. * If it's called on the same region of memory simultaneously, the effect * may be that only one operation succeeds. */ static inline void generic_set_bit(int nr, volatile unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); *p |= mask; } static inline void generic_clear_bit(int nr, volatile unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); *p &= ~mask; } /* * test_bit - Determine whether a bit is set * @nr: bit number to test * @addr: Address to start counting from */ static __inline__ int test_bit(int nr, volatile void *addr) { return ((1UL << (nr & 31)) & (((const unsigned int *) addr)[nr >> 5])) != 0; } /* * test_and_set_bit - Set a bit and return its old value * @nr: Bit to set * @addr: Address to count from * * This operation is non-atomic and can be reordered. * If two examples of this operation race, one can appear to succeed * but actually fail. You must protect multiple accesses with a lock. */ static __inline__ int test_and_set_bit(int nr, volatile void * addr) { int mask, retval; volatile int *a = addr; a += nr >> 5; mask = 1 << (nr & 0x1f); retval = (mask & *a) != 0; *a |= mask; return retval; } #endif