linux 位操作c语言

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Linux 内核 bitops 非原子操作实现。

static inline void set_bit(int bit, volatile unsigned long *addr){  unsigned long mask = BIT_MASK(bit);  unsigned long *p = ((unsigned long *)addr) + BIT_WORD(bit);  *p |= mask;}static inline void clear_bit(unsigned int bit, volatile unsigned long *addr){  unsigned long mask = BIT_MASK(bit);  unsigned long *p = ((unsigned long *)addr) + BIT_WORD(bit);  *p &= ~mask;}static inline void change_bit(unsigned int bit, volatile unsigned long *addr){  unsigned long mask = BIT_MASK(bit);  unsigned long *p = ((unsigned long *)addr) + BIT_WORD(bit);  *p ^= mask;}static inline inttest_and_set_bit(unsigned int bit, volatile unsigned long *addr){  unsigned int res;  unsigned long mask = BIT_MASK(bit);  unsigned long *p = ((unsigned long *)addr) + BIT_WORD(bit);  res = *p;  *p = res | mask;  return (res & mask) != 0;}static inline inttest_and_clear_bit(unsigned int bit, volatile unsigned long *addr){  unsigned int res;  unsigned long mask = BIT_MASK(bit);  unsigned long *p = ((unsigned long *)addr) + BIT_WORD(bit);  res = *p;  *p = res & ~mask;  return (res & mask) != 0;}static inline inttest_and_change_bit(unsigned int bit, volatile unsigned long *addr){  unsigned int res;  unsigned long mask = BIT_MASK(bit);  unsigned long *p = ((unsigned long *)addr) + BIT_WORD(bit);  res = *p;  *p = res ^ mask;  return (res & mask) != 0;}

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