/*
* 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
