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#ifndef _I386_BITOPS_H #define _I386_BITOPS_H /* * Copyright 1992, Linus Torvalds. */ #include <linux/config.h> #include <linux/compiler.h> /* * These have to be done with inline assembly: that way the bit-setting * is guaranteed to be atomic. All bit operations return 0 if the bit * was cleared before the operation and != 0 if it was not. * * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1). */ #ifdef CONFIG_SMP #define LOCK_PREFIX "lock ; " #else #define LOCK_PREFIX "" #endif #define ADDR (*(volatile long *) addr) /** * set_bit - Atomically set a bit in memory * @nr: the bit to set * @addr: the address to start counting from * * This function is atomic and may not be reordered. See __set_bit() * if you do not require the atomic guarantees. * * Note: there are no guarantees that this function will not be reordered * on non x86 architectures, so if you are writting portable code, * make sure not to rely on its reordering guarantees. * * Note that @nr may be almost arbitrarily large; this function is not * restricted to acting on a single-word quantity. */ static inline void set_bit(int nr, volatile unsigned long * addr) { __asm__ __volatile__( LOCK_PREFIX "btsl %1,%0" :"+m" (ADDR) :"Ir" (nr)); } /** * __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 __set_bit(int nr, volatile unsigned long * addr) { __asm__( "btsl %1,%0" :"+m" (ADDR) :"Ir" (nr)); } /** * clear_bit - Clears a bit in memory * @nr: Bit to clear * @addr: Address to start counting from * * clear_bit() is atomic and may not be reordered. However, it does * not contain a memory barrier, so if it is used for locking purposes, * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit() * in order to ensure changes are visible on other processors. */ static inline void clear_bit(int nr, volatile unsigned long * addr) { __asm__ __volatile__( LOCK_PREFIX "btrl %1,%0" :"+m" (ADDR) :"Ir" (nr)); } static inline void __clear_bit(int nr, volatile unsigned long * addr) { __asm__ __volatile__( "btrl %1,%0" :"+m" (ADDR) :"Ir" (nr)); } #define smp_mb__before_clear_bit() barrier() #define smp_mb__after_clear_bit() barrier() /** * __change_bit - Toggle a bit in memory * @nr: the bit to change * @addr: the address to start counting from * * Unlike change_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 __change_bit(int nr, volatile unsigned long * addr) { __asm__ __volatile__( "btcl %1,%0" :"+m" (ADDR) :"Ir" (nr)); } /** * change_bit - Toggle a bit in memory * @nr: Bit to change * @addr: Address to start counting from * * change_bit() is atomic and may not be reordered. It may be * reordered on other architectures than x86. * Note that @nr may be almost arbitrarily large; this function is not * restricted to acting on a single-word quantity. */ static inline void change_bit(int nr, volatile unsigned long * addr) { __asm__ __volatile__( LOCK_PREFIX "btcl %1,%0" :"+m" (ADDR) :"Ir" (nr)); } /** * test_and_set_bit - Set a bit and return its old value * @nr: Bit to set * @addr: Address to count from * * This operation is atomic and cannot be reordered. * It may be reordered on other architectures than x86. * It also implies a memory barrier. */ static inline int test_and_set_bit(int nr, volatile unsigned long * addr) { int oldbit; __asm__ __volatile__( LOCK_PREFIX "btsl %2,%1\n\tsbbl %0,%0" :"=r" (oldbit),"+m" (ADDR) :"Ir" (nr) : "memory"); return oldbit; } /** * __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 unsigned long * addr) { int oldbit; __asm__( "btsl %2,%1\n\tsbbl %0,%0" :"=r" (oldbit),"+m" (ADDR) :"Ir" (nr)); return oldbit; } /** * test_and_clear_bit - Clear a bit and return its old value * @nr: Bit to clear * @addr: Address to count from * * This operation is atomic and cannot be reordered. * It can be reorderdered on other architectures other than x86. * It also implies a memory barrier. */ static inline int test_and_clear_bit(int nr, volatile unsigned long * addr) { int oldbit; __asm__ __volatile__( LOCK_PREFIX "btrl %2,%1\n\tsbbl %0,%0" :"=r" (oldbit),"+m" (ADDR) :"Ir" (nr) : "memory"); return oldbit; } /** * __test_and_clear_bit - Clear a bit and return its old value * @nr: Bit to clear * @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_clear_bit(int nr, volatile unsigned long *addr) { int oldbit; __asm__( "btrl %2,%1\n\tsbbl %0,%0" :"=r" (oldbit),"+m" (ADDR) :"Ir" (nr)); return oldbit; } /* WARNING: non atomic and it can be reordered! */ static inline int __test_and_change_bit(int nr, volatile unsigned long *addr) { int oldbit; __asm__ __volatile__( "btcl %2,%1\n\tsbbl %0,%0" :"=r" (oldbit),"+m" (ADDR) :"Ir" (nr) : "memory"); return oldbit; } /** * test_and_change_bit - Change a bit and return its old value * @nr: Bit to change * @addr: Address to count from * * This operation is atomic and cannot be reordered. * It also implies a memory barrier. */ static inline int test_and_change_bit(int nr, volatile unsigned long* addr) { int oldbit; __asm__ __volatile__( LOCK_PREFIX "btcl %2,%1\n\tsbbl %0,%0" :"=r" (oldbit),"+m" (ADDR) :"Ir" (nr) : "memory"); return oldbit; } #if 0 /* Fool kernel-doc since it doesn't do macros yet */ /** * test_bit - Determine whether a bit is set * @nr: bit number to test * @addr: Address to start counting from */ static int test_bit(int nr, const volatile void * addr); #endif static __always_inline int constant_test_bit(int nr, const volatile unsigned long *addr) { return ((1UL << (nr & 31)) & (addr[nr >> 5])) != 0; } static inline int variable_test_bit(int nr, const volatile unsigned long * addr) { int oldbit; __asm__ __volatile__( "btl %2,%1\n\tsbbl %0,%0" :"=r" (oldbit) :"m" (ADDR),"Ir" (nr)); return oldbit; } #define test_bit(nr,addr) \ (__builtin_constant_p(nr) ? \ constant_test_bit((nr),(addr)) : \ variable_test_bit((nr),(addr))) #undef ADDR /** * find_first_zero_bit - find the first zero bit in a memory region * @addr: The address to start the search at * @size: The maximum size to search * * Returns the bit-number of the first zero bit, not the number of the byte * containing a bit. */ static inline int find_first_zero_bit(const unsigned long *addr, unsigned size) { int d0, d1, d2; int res; if (!size) return 0; /* This looks at memory. Mark it volatile to tell gcc not to move it around */ __asm__ __volatile__( "movl $-1,%%eax\n\t" "xorl %%edx,%%edx\n\t" "repe; scasl\n\t" "je 1f\n\t" "xorl -4(%%edi),%%eax\n\t" "subl $4,%%edi\n\t" "bsfl %%eax,%%edx\n" "1:\tsubl %%ebx,%%edi\n\t" "shll $3,%%edi\n\t" "addl %%edi,%%edx" :"=d" (res), "=&c" (d0), "=&D" (d1), "=&a" (d2) :"1" ((size + 31) >> 5), "2" (addr), "b" (addr) : "memory"); return res; } /** * find_next_zero_bit - find the first zero bit in a memory region * @addr: The address to base the search on * @offset: The bitnumber to start searching at * @size: The maximum size to search */ int find_next_zero_bit(const unsigned long *addr, int size, int offset); /** * __ffs - find first bit in word. * @word: The word to search * * Undefined if no bit exists, so code should check against 0 first. */ static inline unsigned long __ffs(unsigned long word) { __asm__("bsfl %1,%0" :"=r" (word) :"rm" (word)); return word; } /** * find_first_bit - find the first set bit in a memory region * @addr: The address to start the search at * @size: The maximum size to search * * Returns the bit-number of the first set bit, not the number of the byte * containing a bit. */ static inline unsigned find_first_bit(const unsigned long *addr, unsigned size) { unsigned x = 0; while (x < size) { unsigned long val = *addr++; if (val) return __ffs(val) + x; x += (sizeof(*addr)<<3); } return x; } /** * find_next_bit - find the first set bit in a memory region * @addr: The address to base the search on * @offset: The bitnumber to start searching at * @size: The maximum size to search */ int find_next_bit(const unsigned long *addr, int size, int offset); /** * ffz - find first zero in word. * @word: The word to search * * Undefined if no zero exists, so code should check against ~0UL first. */ static inline unsigned long ffz(unsigned long word) { __asm__("bsfl %1,%0" :"=r" (word) :"r" (~word)); return word; } #define fls64(x) generic_fls64(x) #ifdef __KERNEL__ /* * Every architecture must define this function. It's the fastest * way of searching a 140-bit bitmap where the first 100 bits are * unlikely to be set. It's guaranteed that at least one of the 140 * bits is cleared. */ static inline int sched_find_first_bit(const unsigned long *b) { if (unlikely(b[0])) return __ffs(b[0]); if (unlikely(b[1])) return __ffs(b[1]) + 32; if (unlikely(b[2])) return __ffs(b[2]) + 64; if (b[3]) return __ffs(b[3]) + 96; return __ffs(b[4]) + 128; } /** * 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 ffs(int x) { int r; __asm__("bsfl %1,%0\n\t" "jnz 1f\n\t" "movl $-1,%0\n" "1:" : "=r" (r) : "rm" (x)); return r+1; } /** * fls - find last bit set * @x: the word to search * * This is defined the same way as ffs. */ static inline int fls(int x) { int r; __asm__("bsrl %1,%0\n\t" "jnz 1f\n\t" "movl $-1,%0\n" "1:" : "=r" (r) : "rm" (x)); return r+1; } /** * hweightN - returns the hamming weight of a N-bit word * @x: the word to weigh * * The Hamming Weight of a number is the total number of bits set in it. */ #define hweight32(x) generic_hweight32(x) #define hweight16(x) generic_hweight16(x) #define hweight8(x) generic_hweight8(x) #endif /* __KERNEL__ */ #ifdef __KERNEL__ #define ext2_set_bit(nr,addr) \ __test_and_set_bit((nr),(unsigned long*)addr) #define ext2_set_bit_atomic(lock,nr,addr) \ test_and_set_bit((nr),(unsigned long*)addr) #define ext2_clear_bit(nr, addr) \ __test_and_clear_bit((nr),(unsigned long*)addr) #define ext2_clear_bit_atomic(lock,nr, addr) \ test_and_clear_bit((nr),(unsigned long*)addr) #define ext2_test_bit(nr, addr) test_bit((nr),(unsigned long*)addr) #define ext2_find_first_zero_bit(addr, size) \ find_first_zero_bit((unsigned long*)addr, size) #define ext2_find_next_zero_bit(addr, size, off) \ find_next_zero_bit((unsigned long*)addr, size, off) /* Bitmap functions for the minix filesystem. */ #define minix_test_and_set_bit(nr,addr) __test_and_set_bit(nr,(void*)addr) #define minix_set_bit(nr,addr) __set_bit(nr,(void*)addr) #define minix_test_and_clear_bit(nr,addr) __test_and_clear_bit(nr,(void*)addr) #define minix_test_bit(nr,addr) test_bit(nr,(void*)addr) #define minix_find_first_zero_bit(addr,size) \ find_first_zero_bit((void*)addr,size) #endif /* __KERNEL__ */ #endif /* _I386_BITOPS_H */