151 lines
3.7 KiB
C
151 lines
3.7 KiB
C
#ifndef _ASM_GENERIC_BITOPS_NON_ATOMIC_H_
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#define _ASM_GENERIC_BITOPS_NON_ATOMIC_H_
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#include <linux/types.h>
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#define BITOP_MASK(nr) (1UL << ((nr) % BITS_PER_LONG))
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#define BITOP_WORD(nr) ((nr) / BITS_PER_LONG)
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/**
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* __set_bit - Set a bit in memory
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* @nr: the bit to set
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* @addr: the address to start counting from
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*
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* Unlike set_bit(), this function is non-atomic and may be reordered.
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* If it's called on the same region of memory simultaneously, the effect
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* may be that only one operation succeeds.
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*/
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static inline void __set_bit(int nr, volatile unsigned long *addr)
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{
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unsigned long mask = BITOP_MASK(nr);
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unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
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*p |= mask;
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}
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static inline void __clear_bit(int nr, volatile unsigned long *addr)
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{
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unsigned long mask = BITOP_MASK(nr);
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unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
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*p &= ~mask;
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}
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/**
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* __change_bit - Toggle a bit in memory
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* @nr: the bit to change
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* @addr: the address to start counting from
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*
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* Unlike change_bit(), this function is non-atomic and may be reordered.
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* If it's called on the same region of memory simultaneously, the effect
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* may be that only one operation succeeds.
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*/
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static inline void __change_bit(int nr, volatile unsigned long *addr)
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{
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unsigned long mask = BITOP_MASK(nr);
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unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
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*p ^= mask;
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}
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/**
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* __test_and_set_bit - Set a bit and return its old value
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* @nr: Bit to set
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* @addr: Address to count from
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*
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* This operation is non-atomic and can be reordered.
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* If two examples of this operation race, one can appear to succeed
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* but actually fail. You must protect multiple accesses with a lock.
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*/
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static inline int __test_and_set_bit(int nr, volatile unsigned long *addr)
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{
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unsigned long mask = BITOP_MASK(nr);
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unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
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unsigned long old = *p;
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*p = old | mask;
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return (old & mask) != 0;
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}
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/**
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* __test_and_clear_bit - Clear a bit and return its old value
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* @nr: Bit to clear
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* @addr: Address to count from
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*
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* This operation is non-atomic and can be reordered.
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* If two examples of this operation race, one can appear to succeed
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* but actually fail. You must protect multiple accesses with a lock.
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*/
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static inline int __test_and_clear_bit(int nr, volatile unsigned long *addr)
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{
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unsigned long mask = BITOP_MASK(nr);
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unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
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unsigned long old = *p;
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*p = old & ~mask;
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return (old & mask) != 0;
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}
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/* WARNING: non atomic and it can be reordered! */
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static inline int __test_and_change_bit(int nr,
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volatile unsigned long *addr)
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{
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unsigned long mask = BITOP_MASK(nr);
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unsigned long *p = ((unsigned long *)addr) + BITOP_WORD(nr);
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unsigned long old = *p;
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*p = old ^ mask;
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return (old & mask) != 0;
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}
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/**
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* test_bit - Determine whether a bit is set
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* @nr: bit number to test
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* @addr: Address to start counting from
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*/
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static inline int test_bit(int nr, const volatile unsigned long *addr)
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{
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return 1UL & (addr[BITOP_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
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}
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/**
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* __ffs - find first bit in word.
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* @word: The word to search
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*
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* Undefined if no bit exists, so code should check against 0 first.
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*/
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static inline unsigned long __ffs(unsigned long word)
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{
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int num = 0;
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if ((word & 0xffffffff) == 0) {
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num += 32;
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word >>= 32;
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}
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if ((word & 0xffff) == 0) {
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num += 16;
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word >>= 16;
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}
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if ((word & 0xff) == 0) {
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num += 8;
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word >>= 8;
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}
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if ((word & 0xf) == 0) {
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num += 4;
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word >>= 4;
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}
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if ((word & 0x3) == 0) {
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num += 2;
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word >>= 2;
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}
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if ((word & 0x1) == 0)
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num += 1;
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return num;
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}
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unsigned long find_next_bit(const unsigned long *addr,
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unsigned long size,
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unsigned long offset);
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#endif /* _ASM_GENERIC_BITOPS_NON_ATOMIC_H_ */
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