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| #ifndef _I386_BITOPS_H |
| #define _I386_BITOPS_H |
| |
| /* |
| * Copyright 1992, Linus Torvalds. |
| */ |
| |
| /* |
| * 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 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 void * 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 void * 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 void * addr) |
| { |
| __asm__ __volatile__( LOCK_PREFIX |
| "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 set |
| * @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 void * addr) |
| { |
| __asm__ __volatile__( |
| "btcl %1,%0" |
| :"=m" (ADDR) |
| :"Ir" (nr)); |
| } |
| |
| /** |
| * change_bit - Toggle a bit in memory |
| * @nr: Bit to clear |
| * @addr: Address to start counting from |
| * |
| * change_bit() is atomic and may not be reordered. |
| * 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 void * 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 also implies a memory barrier. |
| */ |
| static __inline__ int test_and_set_bit(int nr, volatile void * 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 void * 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 set |
| * @addr: Address to count from |
| * |
| * This operation is atomic and cannot be reordered. |
| * It also implies a memory barrier. |
| */ |
| static __inline__ int test_and_clear_bit(int nr, volatile void * 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 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_clear_bit(int nr, volatile void * 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 void * 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 new value |
| * @nr: Bit to set |
| * @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 void * 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 __inline__ int constant_test_bit(int nr, const volatile void * addr) |
| { |
| return ((1UL << (nr & 31)) & (((const volatile unsigned int *) addr)[nr >> 5])) != 0; |
| } |
| |
| static __inline__ int variable_test_bit(int nr, volatile void * 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))) |
| |
| /** |
| * 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(void * 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)); |
| 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 |
| */ |
| static __inline__ int find_next_zero_bit (void * addr, int size, int offset) |
| { |
| unsigned long * p = ((unsigned long *) addr) + (offset >> 5); |
| int set = 0, bit = offset & 31, res; |
| |
| if (bit) { |
| /* |
| * Look for zero in first byte |
| */ |
| __asm__("bsfl %1,%0\n\t" |
| "jne 1f\n\t" |
| "movl $32, %0\n" |
| "1:" |
| : "=r" (set) |
| : "r" (~(*p >> bit))); |
| if (set < (32 - bit)) |
| return set + offset; |
| set = 32 - bit; |
| p++; |
| } |
| /* |
| * No zero yet, search remaining full bytes for a zero |
| */ |
| res = find_first_zero_bit (p, size - 32 * (p - (unsigned long *) addr)); |
| return (offset + set + res); |
| } |
| |
| /** |
| * 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; |
| } |
| |
| #ifdef __KERNEL__ |
| |
| /** |
| * 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; |
| } |
| |
| /** |
| * 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 __test_and_set_bit |
| #define ext2_clear_bit __test_and_clear_bit |
| #define ext2_test_bit test_bit |
| #define ext2_find_first_zero_bit find_first_zero_bit |
| #define ext2_find_next_zero_bit find_next_zero_bit |
| |
| /* Bitmap functions for the minix filesystem. */ |
| #define minix_test_and_set_bit(nr,addr) __test_and_set_bit(nr,addr) |
| #define minix_set_bit(nr,addr) __set_bit(nr,addr) |
| #define minix_test_and_clear_bit(nr,addr) __test_and_clear_bit(nr,addr) |
| #define minix_test_bit(nr,addr) test_bit(nr,addr) |
| #define minix_find_first_zero_bit(addr,size) find_first_zero_bit(addr,size) |
| |
| #endif /* __KERNEL__ */ |
| |
| #endif /* _I386_BITOPS_H */ |