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/*
* Copyright 1995, Russell King.
* Various bits and pieces copyrights include:
* Linus Torvalds (test_bit).
* Big endian support: Copyright 2001, Nicolas Pitre
* reworked by rmk.
*/
#ifndef _ARM_BITOPS_H
#define _ARM_BITOPS_H
/*
* Non-atomic bit manipulation.
*
* Implemented using atomics to be interrupt safe. Could alternatively
* implement with local interrupt masking.
*/
#define __set_bit(n,p) set_bit(n,p)
#define __clear_bit(n,p) clear_bit(n,p)
#define BIT(nr) (1UL << (nr))
#define BIT_MASK(nr) (1UL << ((nr) % BITS_PER_LONG))
#define BIT_WORD(nr) ((nr) / BITS_PER_LONG)
#define BITS_PER_BYTE 8
#define ADDR (*(volatile long *) addr)
#define CONST_ADDR (*(const volatile long *) addr)
#if defined(CONFIG_ARM_32)
# include <asm/arm32/bitops.h>
#elif defined(CONFIG_ARM_64)
# include <asm/arm64/bitops.h>
#else
# error "unknown ARM variant"
#endif
/**
* __test_and_set_bit - Set a bit and return its old value
* @nr: Bit to set
* @addr: Address to count from
*
* This operation is non-atomic and can be reordered.
* If two examples of this operation race, one can appear to succeed
* but actually fail. You must protect multiple accesses with a lock.
*/
static inline int __test_and_set_bit(int nr, volatile void *addr)
{
unsigned long mask = BIT_MASK(nr);
volatile unsigned long *p =
((volatile 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
*
* This operation is non-atomic and can be reordered.
* If two examples of this operation race, one can appear to succeed
* but actually fail. You must protect multiple accesses with a lock.
*/
static inline int __test_and_clear_bit(int nr, volatile void *addr)
{
unsigned long mask = BIT_MASK(nr);
volatile unsigned long *p =
((volatile unsigned long *)addr) + BIT_WORD(nr);
unsigned long old = *p;
*p = old & ~mask;
return (old & mask) != 0;
}
/* WARNING: non atomic and it can be reordered! */
static inline int __test_and_change_bit(int nr,
volatile void *addr)
{
unsigned long mask = BIT_MASK(nr);
volatile unsigned long *p =
((volatile 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 void *addr)
{
const volatile unsigned long *p = (const volatile unsigned long *)addr;
return 1UL & (p[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
}
static inline int constant_fls(int x)
{
int r = 32;
if (!x)
return 0;
if (!(x & 0xffff0000u)) {
x <<= 16;
r -= 16;
}
if (!(x & 0xff000000u)) {
x <<= 8;
r -= 8;
}
if (!(x & 0xf0000000u)) {
x <<= 4;
r -= 4;
}
if (!(x & 0xc0000000u)) {
x <<= 2;
r -= 2;
}
if (!(x & 0x80000000u)) {
x <<= 1;
r -= 1;
}
return r;
}
/*
* On ARMv5 and above those functions can be implemented around
* the clz instruction for much better code efficiency.
*/
static inline int fls(int x)
{
int ret;
if (__builtin_constant_p(x))
return constant_fls(x);
asm("clz\t%0, %1" : "=r" (ret) : "r" (x));
ret = BITS_PER_LONG - ret;
return ret;
}
#define ffs(x) ({ unsigned long __t = (x); fls(__t & -__t); })
/**
* find_first_set_bit - find the first set bit in @word
* @word: the word to search
*
* Returns the bit-number of the first set bit (first bit being 0).
* The input must *not* be zero.
*/
static inline unsigned int find_first_set_bit(unsigned long word)
{
return ffs(word) - 1;
}
/**
* hweightN - returns the hamming weight of a N-bit word
* @x: the word to weigh
*
* The Hamming Weight of a number is the total number of bits set in it.
*/
#define hweight64(x) generic_hweight64(x)
#define hweight32(x) generic_hweight32(x)
#define hweight16(x) generic_hweight16(x)
#define hweight8(x) generic_hweight8(x)
#endif /* _ARM_BITOPS_H */
/*
* Local variables:
* mode: C
* c-file-style: "BSD"
* c-basic-offset: 4
* indent-tabs-mode: nil
* End:
*/
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