qemu-android / qemu-android / b6ea621b4708e0ad4415b49d3585ef5cac77469c / . / include / qemu / bitops.h

/* | |

* 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 "host-utils.h" | |

#include "atomic.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)) | |

#define MAKE_64BIT_MASK(shift, length) \ | |

(((~0ULL) >> (64 - (length))) << (shift)) | |

/** | |

* set_bit - Set a bit in memory | |

* @nr: the bit to set | |

* @addr: the address to start counting from | |

*/ | |

static inline void set_bit(long nr, unsigned long *addr) | |

{ | |

unsigned long mask = BIT_MASK(nr); | |

unsigned long *p = addr + BIT_WORD(nr); | |

*p |= mask; | |

} | |

/** | |

* set_bit_atomic - Set a bit in memory atomically | |

* @nr: the bit to set | |

* @addr: the address to start counting from | |

*/ | |

static inline void set_bit_atomic(long nr, unsigned long *addr) | |

{ | |

unsigned long mask = BIT_MASK(nr); | |

unsigned long *p = addr + BIT_WORD(nr); | |

atomic_or(p, mask); | |

} | |

/** | |

* clear_bit - Clears a bit in memory | |

* @nr: Bit to clear | |

* @addr: Address to start counting from | |

*/ | |

static inline void clear_bit(long 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(long 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(long 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(long 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(long 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(long 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) | |

{ | |

unsigned long result, tmp; | |

for (result = 0; result < size; result += BITS_PER_LONG) { | |

tmp = *addr++; | |

if (tmp) { | |

result += ctzl(tmp); | |

return result < size ? result : size; | |

} | |

} | |

/* Not found */ | |

return size; | |

} | |

/** | |

* 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; | |

} | |

/** | |

* rol8 - rotate an 8-bit value left | |

* @word: value to rotate | |

* @shift: bits to roll | |

*/ | |

static inline uint8_t rol8(uint8_t word, unsigned int shift) | |

{ | |

return (word << shift) | (word >> (8 - shift)); | |

} | |

/** | |

* ror8 - rotate an 8-bit value right | |

* @word: value to rotate | |

* @shift: bits to roll | |

*/ | |

static inline uint8_t ror8(uint8_t word, unsigned int shift) | |

{ | |

return (word >> shift) | (word << (8 - shift)); | |

} | |

/** | |

* rol16 - rotate a 16-bit value left | |

* @word: value to rotate | |

* @shift: bits to roll | |

*/ | |

static inline uint16_t rol16(uint16_t word, unsigned int shift) | |

{ | |

return (word << shift) | (word >> (16 - shift)); | |

} | |

/** | |

* ror16 - rotate a 16-bit value right | |

* @word: value to rotate | |

* @shift: bits to roll | |

*/ | |

static inline uint16_t ror16(uint16_t word, unsigned int shift) | |

{ | |

return (word >> shift) | (word << (16 - shift)); | |

} | |

/** | |

* rol32 - rotate a 32-bit value left | |

* @word: value to rotate | |

* @shift: bits to roll | |

*/ | |

static inline uint32_t rol32(uint32_t word, unsigned int shift) | |

{ | |

return (word << shift) | (word >> (32 - shift)); | |

} | |

/** | |

* ror32 - rotate a 32-bit value right | |

* @word: value to rotate | |

* @shift: bits to roll | |

*/ | |

static inline uint32_t ror32(uint32_t word, unsigned int shift) | |

{ | |

return (word >> shift) | (word << (32 - shift)); | |

} | |

/** | |

* rol64 - rotate a 64-bit value left | |

* @word: value to rotate | |

* @shift: bits to roll | |

*/ | |

static inline uint64_t rol64(uint64_t word, unsigned int shift) | |

{ | |

return (word << shift) | (word >> (64 - shift)); | |

} | |

/** | |

* ror64 - rotate a 64-bit value right | |

* @word: value to rotate | |

* @shift: bits to roll | |

*/ | |

static inline uint64_t ror64(uint64_t word, unsigned int shift) | |

{ | |

return (word >> shift) | (word << (64 - shift)); | |

} | |

/** | |

* 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)); | |

} | |

/** | |

* sextract32: | |

* @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, sign extended to | |

* an int32_t (ie with the most significant bit of the field propagated | |

* to all the upper bits of the return value). 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 sign extended value of the bit field extracted from the | |

* input value. | |

*/ | |

static inline int32_t sextract32(uint32_t value, int start, int length) | |

{ | |

assert(start >= 0 && length > 0 && length <= 32 - start); | |

/* Note that this implementation relies on right shift of signed | |

* integers being an arithmetic shift. | |

*/ | |

return ((int32_t)(value << (32 - length - start))) >> (32 - length); | |

} | |

/** | |

* sextract64: | |

* @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, sign extended to | |

* an int64_t (ie with the most significant bit of the field propagated | |

* to all the upper bits of the return value). 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 sign extended value of the bit field extracted from the | |

* input value. | |

*/ | |

static inline int64_t sextract64(uint64_t value, int start, int length) | |

{ | |

assert(start >= 0 && length > 0 && length <= 64 - start); | |

/* Note that this implementation relies on right shift of signed | |

* integers being an arithmetic shift. | |

*/ | |

return ((int64_t)(value << (64 - length - start))) >> (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); | |

} | |

/** | |

* half_shuffle32: | |

* @value: 32-bit value (of which only the bottom 16 bits are of interest) | |

* | |

* Given an input value: | |

* xxxx xxxx xxxx xxxx ABCD EFGH IJKL MNOP | |

* return the value where the bottom 16 bits are spread out into | |

* the odd bits in the word, and the even bits are zeroed: | |

* 0A0B 0C0D 0E0F 0G0H 0I0J 0K0L 0M0N 0O0P | |

* | |

* Any bits set in the top half of the input are ignored. | |

* | |

* Returns: the shuffled bits. | |

*/ | |

static inline uint32_t half_shuffle32(uint32_t x) | |

{ | |

/* This algorithm is from _Hacker's Delight_ section 7-2 "Shuffling Bits". | |

* It ignores any bits set in the top half of the input. | |

*/ | |

x = ((x & 0xFF00) << 8) | (x & 0x00FF); | |

x = ((x << 4) | x) & 0x0F0F0F0F; | |

x = ((x << 2) | x) & 0x33333333; | |

x = ((x << 1) | x) & 0x55555555; | |

return x; | |

} | |

/** | |

* half_shuffle64: | |

* @value: 64-bit value (of which only the bottom 32 bits are of interest) | |

* | |

* Given an input value: | |

* xxxx xxxx xxxx .... xxxx xxxx ABCD EFGH IJKL MNOP QRST UVWX YZab cdef | |

* return the value where the bottom 32 bits are spread out into | |

* the odd bits in the word, and the even bits are zeroed: | |

* 0A0B 0C0D 0E0F 0G0H 0I0J 0K0L 0M0N .... 0U0V 0W0X 0Y0Z 0a0b 0c0d 0e0f | |

* | |

* Any bits set in the top half of the input are ignored. | |

* | |

* Returns: the shuffled bits. | |

*/ | |

static inline uint64_t half_shuffle64(uint64_t x) | |

{ | |

/* This algorithm is from _Hacker's Delight_ section 7-2 "Shuffling Bits". | |

* It ignores any bits set in the top half of the input. | |

*/ | |

x = ((x & 0xFFFF0000ULL) << 16) | (x & 0xFFFF); | |

x = ((x << 8) | x) & 0x00FF00FF00FF00FFULL; | |

x = ((x << 4) | x) & 0x0F0F0F0F0F0F0F0FULL; | |

x = ((x << 2) | x) & 0x3333333333333333ULL; | |

x = ((x << 1) | x) & 0x5555555555555555ULL; | |

return x; | |

} | |

/** | |

* half_unshuffle32: | |

* @value: 32-bit value (of which only the odd bits are of interest) | |

* | |

* Given an input value: | |

* xAxB xCxD xExF xGxH xIxJ xKxL xMxN xOxP | |

* return the value where all the odd bits are compressed down | |

* into the low half of the word, and the high half is zeroed: | |

* 0000 0000 0000 0000 ABCD EFGH IJKL MNOP | |

* | |

* Any even bits set in the input are ignored. | |

* | |

* Returns: the unshuffled bits. | |

*/ | |

static inline uint32_t half_unshuffle32(uint32_t x) | |

{ | |

/* This algorithm is from _Hacker's Delight_ section 7-2 "Shuffling Bits". | |

* where it is called an inverse half shuffle. | |

*/ | |

x &= 0x55555555; | |

x = ((x >> 1) | x) & 0x33333333; | |

x = ((x >> 2) | x) & 0x0F0F0F0F; | |

x = ((x >> 4) | x) & 0x00FF00FF; | |

x = ((x >> 8) | x) & 0x0000FFFF; | |

return x; | |

} | |

/** | |

* half_unshuffle64: | |

* @value: 64-bit value (of which only the odd bits are of interest) | |

* | |

* Given an input value: | |

* xAxB xCxD xExF xGxH xIxJ xKxL xMxN .... xUxV xWxX xYxZ xaxb xcxd xexf | |

* return the value where all the odd bits are compressed down | |

* into the low half of the word, and the high half is zeroed: | |

* 0000 0000 0000 .... 0000 0000 ABCD EFGH IJKL MNOP QRST UVWX YZab cdef | |

* | |

* Any even bits set in the input are ignored. | |

* | |

* Returns: the unshuffled bits. | |

*/ | |

static inline uint64_t half_unshuffle64(uint64_t x) | |

{ | |

/* This algorithm is from _Hacker's Delight_ section 7-2 "Shuffling Bits". | |

* where it is called an inverse half shuffle. | |

*/ | |

x &= 0x5555555555555555ULL; | |

x = ((x >> 1) | x) & 0x3333333333333333ULL; | |

x = ((x >> 2) | x) & 0x0F0F0F0F0F0F0F0FULL; | |

x = ((x >> 4) | x) & 0x00FF00FF00FF00FFULL; | |

x = ((x >> 8) | x) & 0x0000FFFF0000FFFFULL; | |

x = ((x >> 16) | x) & 0x00000000FFFFFFFFULL; | |

return x; | |

} | |

#endif |