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/*

 * 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, unsigned long *addr)

{

        unsigned long mask = BIT_MASK(nr);

        unsigned long *p = 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, unsigned long *addr)

{

        unsigned long mask = BIT_MASK(nr);

        unsigned long *p = 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, unsigned long *addr)

{

        unsigned long mask = BIT_MASK(nr);

        unsigned long *p = 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, unsigned long *addr)

{

        unsigned long mask = BIT_MASK(nr);

        unsigned long *p = 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, unsigned long *addr)

{

        unsigned long mask = BIT_MASK(nr);

        unsigned long *p = 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, unsigned long *addr)

{

        unsigned long mask = BIT_MASK(nr);

        unsigned long *p = 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 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