/* * Bitops Module * * Copyright (C) 2010 Corentin Chary <corentin.chary@gmail.com> * * Mostly inspired by (stolen from) linux/bitmap.h and linux/bitops.h * * This work is licensed under the terms of the GNU LGPL, version 2.1 or later. * See the COPYING.LIB file in the top-level directory. */ #ifndef BITOPS_H #define BITOPS_H #include "qemu-common.h" #define BITS_PER_BYTE CHAR_BIT #define BITS_PER_LONG (sizeof (unsigned long) * BITS_PER_BYTE) #define BIT(nr) (1UL << (nr)) #define BIT_MASK(nr) (1UL << ((nr) % BITS_PER_LONG)) #define BIT_WORD(nr) ((nr) / BITS_PER_LONG) #define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long)) /** * bitops_ffs - find first bit in word. * @word: The word to search * * Undefined if no bit exists, so code should check against 0 first. */ static unsigned long bitops_ffsl(unsigned long word) { int num = 0; #if LONG_MAX > 0x7FFFFFFF if ((word & 0xffffffff) == 0) { num += 32; word >>= 32; } #endif if ((word & 0xffff) == 0) { num += 16; word >>= 16; } if ((word & 0xff) == 0) { num += 8; word >>= 8; } if ((word & 0xf) == 0) { num += 4; word >>= 4; } if ((word & 0x3) == 0) { num += 2; word >>= 2; } if ((word & 0x1) == 0) { num += 1; } return num; } /** * bitops_fls - find last (most-significant) set bit in a long word * @word: the word to search * * Undefined if no set bit exists, so code should check against 0 first. */ static inline unsigned long bitops_flsl(unsigned long word) { int num = BITS_PER_LONG - 1; #if LONG_MAX > 0x7FFFFFFF if (!(word & (~0ul << 32))) { num -= 32; word <<= 32; } #endif if (!(word & (~0ul << (BITS_PER_LONG-16)))) { num -= 16; word <<= 16; } if (!(word & (~0ul << (BITS_PER_LONG-8)))) { num -= 8; word <<= 8; } if (!(word & (~0ul << (BITS_PER_LONG-4)))) { num -= 4; word <<= 4; } if (!(word & (~0ul << (BITS_PER_LONG-2)))) { num -= 2; word <<= 2; } if (!(word & (~0ul << (BITS_PER_LONG-1)))) num -= 1; return num; } /** * 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) { return bitops_ffsl(~word); } /** * set_bit - Set a bit in memory * @nr: the bit to set * @addr: the address to start counting from */ static inline void 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; } /** * clear_bit - Clears a bit in memory * @nr: Bit to clear * @addr: Address to start counting from */ static inline void 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; } /** * change_bit - Toggle a bit in memory * @nr: Bit to change * @addr: Address to start counting from */ static inline void change_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_and_set_bit - Set a bit and return its old value * @nr: Bit to set * @addr: Address to count from */ static inline int test_and_set_bit(int nr, volatile unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); unsigned long old = *p; *p = old | mask; return (old & mask) != 0; } /** * test_and_clear_bit - Clear a bit and return its old value * @nr: Bit to clear * @addr: Address to count from */ static inline int test_and_clear_bit(int nr, volatile unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); unsigned long old = *p; *p = old & ~mask; return (old & mask) != 0; } /** * test_and_change_bit - Change a bit and return its old value * @nr: Bit to change * @addr: Address to count from */ static inline int test_and_change_bit(int nr, volatile unsigned long *addr) { unsigned long mask = BIT_MASK(nr); unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr); unsigned long old = *p; *p = old ^ mask; return (old & mask) != 0; } /** * 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, const volatile unsigned long *addr) { return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1))); } /** * find_last_bit - find the last 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, or size. */ unsigned long find_last_bit(const unsigned long *addr, unsigned long size); /** * find_next_bit - find the next set bit in a memory region * @addr: The address to base the search on * @offset: The bitnumber to start searching at * @size: The bitmap size in bits */ unsigned long find_next_bit(const unsigned long *addr, unsigned long size, unsigned long offset); /** * find_next_zero_bit - find the next cleared bit in a memory region * @addr: The address to base the search on * @offset: The bitnumber to start searching at * @size: The bitmap size in bits */ unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size, unsigned long offset); /** * 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. */ static inline unsigned long find_first_bit(const unsigned long *addr, unsigned long size) { return find_next_bit(addr, size, 0); } /** * find_first_zero_bit - find the first cleared 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 cleared bit. */ static inline unsigned long find_first_zero_bit(const unsigned long *addr, unsigned long size) { return find_next_zero_bit(addr, size, 0); } static inline unsigned long hweight_long(unsigned long w) { unsigned long count; for (count = 0; w; w >>= 1) { count += w & 1; } return count; } /** * extract32: * @value: the value to extract the bit field from * @start: the lowest bit in the bit field (numbered from 0) * @length: the length of the bit field * * Extract from the 32 bit input @value the bit field specified by the * @start and @length parameters, and return it. The bit field must * lie entirely within the 32 bit word. It is valid to request that * all 32 bits are returned (ie @length 32 and @start 0). * * Returns: the value of the bit field extracted from the input value. */ static inline uint32_t extract32(uint32_t value, int start, int length) { assert(start >= 0 && length > 0 && length <= 32 - start); return (value >> start) & (~0U >> (32 - length)); } /** * extract64: * @value: the value to extract the bit field from * @start: the lowest bit in the bit field (numbered from 0) * @length: the length of the bit field * * Extract from the 64 bit input @value the bit field specified by the * @start and @length parameters, and return it. The bit field must * lie entirely within the 64 bit word. It is valid to request that * all 64 bits are returned (ie @length 64 and @start 0). * * Returns: the value of the bit field extracted from the input value. */ static inline uint64_t extract64(uint64_t value, int start, int length) { assert(start >= 0 && length > 0 && length <= 64 - start); return (value >> start) & (~0ULL >> (64 - length)); } /** * deposit32: * @value: initial value to insert bit field into * @start: the lowest bit in the bit field (numbered from 0) * @length: the length of the bit field * @fieldval: the value to insert into the bit field * * Deposit @fieldval into the 32 bit @value at the bit field specified * by the @start and @length parameters, and return the modified * @value. Bits of @value outside the bit field are not modified. * Bits of @fieldval above the least significant @length bits are * ignored. The bit field must lie entirely within the 32 bit word. * It is valid to request that all 32 bits are modified (ie @length * 32 and @start 0). * * Returns: the modified @value. */ static inline uint32_t deposit32(uint32_t value, int start, int length, uint32_t fieldval) { uint32_t mask; assert(start >= 0 && length > 0 && length <= 32 - start); mask = (~0U >> (32 - length)) << start; return (value & ~mask) | ((fieldval << start) & mask); } /** * deposit64: * @value: initial value to insert bit field into * @start: the lowest bit in the bit field (numbered from 0) * @length: the length of the bit field * @fieldval: the value to insert into the bit field * * Deposit @fieldval into the 64 bit @value at the bit field specified * by the @start and @length parameters, and return the modified * @value. Bits of @value outside the bit field are not modified. * Bits of @fieldval above the least significant @length bits are * ignored. The bit field must lie entirely within the 64 bit word. * It is valid to request that all 64 bits are modified (ie @length * 64 and @start 0). * * Returns: the modified @value. */ static inline uint64_t deposit64(uint64_t value, int start, int length, uint64_t fieldval) { uint64_t mask; assert(start >= 0 && length > 0 && length <= 64 - start); mask = (~0ULL >> (64 - length)) << start; return (value & ~mask) | ((fieldval << start) & mask); } #endif