/*
* 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_ULL(nr) (1ULL << (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);
qatomic_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 last set bit,
* or @size if there is no set bit in the bitmap.
*/
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
*
* Returns the bit number of the next set bit,
* or @size if there are no further set bits in the bitmap.
*/
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
*
* Returns the bit number of the next cleared bit,
* or @size if there are no further clear bits in the bitmap.
*/
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,
* or @size if there is no set bit in the bitmap.
*/
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,
* or @size if there is no clear bit in the bitmap.
*/
static inline unsigned long find_first_zero_bit(const unsigned long *addr,
unsigned long size)
{
return find_next_zero_bit(addr, size, 0);
}
/**
* 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) & 7));
}
/**
* 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) & 7));
}
/**
* 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) & 15));
}
/**
* 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) & 15));
}
/**
* 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) & 31));
}
/**
* 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) & 31));
}
/**
* 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) & 63));
}
/**
* 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) & 63));
}
/**
* hswap32 - swap 16-bit halfwords within a 32-bit value
* @h: value to swap
*/
static inline uint32_t hswap32(uint32_t h)
{
return rol32(h, 16);
}
/**
* hswap64 - swap 16-bit halfwords within a 64-bit value
* @h: value to swap
*/
static inline uint64_t hswap64(uint64_t h)
{
uint64_t m = 0x0000ffff0000ffffull;
h = rol64(h, 32);
return ((h & m) << 16) | ((h >> 16) & m);
}
/**
* wswap64 - swap 32-bit words within a 64-bit value
* @h: value to swap
*/
static inline uint64_t wswap64(uint64_t h)
{
return rol64(h, 32);
}
/**
* 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));
}
/**
* extract8:
* @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 8 bit input @value the bit field specified by the
* @start and @length parameters, and return it. The bit field must
* lie entirely within the 8 bit word. It is valid to request that
* all 8 bits are returned (ie @length 8 and @start 0).
*
* Returns: the value of the bit field extracted from the input value.
*/
static inline uint8_t extract8(uint8_t value, int start, int length)
{
assert(start >= 0 && length > 0 && length <= 8 - start);
return extract32(value, start, length);
}
/**
* extract16:
* @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 16 bit input @value the bit field specified by the
* @start and @length parameters, and return it. The bit field must
* lie entirely within the 16 bit word. It is valid to request that
* all 16 bits are returned (ie @length 16 and @start 0).
*
* Returns: the value of the bit field extracted from the input value.
*/
static inline uint16_t extract16(uint16_t value, int start, int length)
{
assert(start >= 0 && length > 0 && length <= 16 - start);
return extract32(value, start, 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:
* @x: 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:
* @x: 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:
* @x: 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:
* @x: 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
