| /* |
| * 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; |
| } |
| |
| #endif |