424 lines
10 KiB
C
424 lines
10 KiB
C
#ifndef _I386_BITOPS_H
|
|
#define _I386_BITOPS_H
|
|
|
|
/*
|
|
* Copyright 1992, Linus Torvalds.
|
|
*/
|
|
|
|
#include <linux/compiler.h>
|
|
#include <asm/alternative.h>
|
|
|
|
/*
|
|
* These have to be done with inline assembly: that way the bit-setting
|
|
* is guaranteed to be atomic. All bit operations return 0 if the bit
|
|
* was cleared before the operation and != 0 if it was not.
|
|
*
|
|
* bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
|
|
*/
|
|
|
|
#define ADDR (*(volatile long *) addr)
|
|
|
|
/**
|
|
* set_bit - Atomically set a bit in memory
|
|
* @nr: the bit to set
|
|
* @addr: the address to start counting from
|
|
*
|
|
* This function is atomic and may not be reordered. See __set_bit()
|
|
* if you do not require the atomic guarantees.
|
|
*
|
|
* Note: there are no guarantees that this function will not be reordered
|
|
* on non x86 architectures, so if you are writing portable code,
|
|
* make sure not to rely on its reordering guarantees.
|
|
*
|
|
* Note that @nr may be almost arbitrarily large; this function is not
|
|
* restricted to acting on a single-word quantity.
|
|
*/
|
|
static inline void set_bit(int nr, volatile unsigned long * addr)
|
|
{
|
|
__asm__ __volatile__( LOCK_PREFIX
|
|
"btsl %1,%0"
|
|
:"+m" (ADDR)
|
|
:"Ir" (nr));
|
|
}
|
|
|
|
/**
|
|
* __set_bit - Set a bit in memory
|
|
* @nr: the bit to set
|
|
* @addr: the address to start counting from
|
|
*
|
|
* Unlike set_bit(), this function is non-atomic and may be reordered.
|
|
* If it's called on the same region of memory simultaneously, the effect
|
|
* may be that only one operation succeeds.
|
|
*/
|
|
static inline void __set_bit(int nr, volatile unsigned long * addr)
|
|
{
|
|
__asm__(
|
|
"btsl %1,%0"
|
|
:"+m" (ADDR)
|
|
:"Ir" (nr));
|
|
}
|
|
|
|
/**
|
|
* clear_bit - Clears a bit in memory
|
|
* @nr: Bit to clear
|
|
* @addr: Address to start counting from
|
|
*
|
|
* clear_bit() is atomic and may not be reordered. However, it does
|
|
* not contain a memory barrier, so if it is used for locking purposes,
|
|
* you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit()
|
|
* in order to ensure changes are visible on other processors.
|
|
*/
|
|
static inline void clear_bit(int nr, volatile unsigned long * addr)
|
|
{
|
|
__asm__ __volatile__( LOCK_PREFIX
|
|
"btrl %1,%0"
|
|
:"+m" (ADDR)
|
|
:"Ir" (nr));
|
|
}
|
|
|
|
static inline void __clear_bit(int nr, volatile unsigned long * addr)
|
|
{
|
|
__asm__ __volatile__(
|
|
"btrl %1,%0"
|
|
:"+m" (ADDR)
|
|
:"Ir" (nr));
|
|
}
|
|
#define smp_mb__before_clear_bit() barrier()
|
|
#define smp_mb__after_clear_bit() barrier()
|
|
|
|
/**
|
|
* __change_bit - Toggle a bit in memory
|
|
* @nr: the bit to change
|
|
* @addr: the address to start counting from
|
|
*
|
|
* Unlike change_bit(), this function is non-atomic and may be reordered.
|
|
* If it's called on the same region of memory simultaneously, the effect
|
|
* may be that only one operation succeeds.
|
|
*/
|
|
static inline void __change_bit(int nr, volatile unsigned long * addr)
|
|
{
|
|
__asm__ __volatile__(
|
|
"btcl %1,%0"
|
|
:"+m" (ADDR)
|
|
:"Ir" (nr));
|
|
}
|
|
|
|
/**
|
|
* change_bit - Toggle a bit in memory
|
|
* @nr: Bit to change
|
|
* @addr: Address to start counting from
|
|
*
|
|
* change_bit() is atomic and may not be reordered. It may be
|
|
* reordered on other architectures than x86.
|
|
* Note that @nr may be almost arbitrarily large; this function is not
|
|
* restricted to acting on a single-word quantity.
|
|
*/
|
|
static inline void change_bit(int nr, volatile unsigned long * addr)
|
|
{
|
|
__asm__ __volatile__( LOCK_PREFIX
|
|
"btcl %1,%0"
|
|
:"+m" (ADDR)
|
|
:"Ir" (nr));
|
|
}
|
|
|
|
/**
|
|
* test_and_set_bit - Set a bit and return its old value
|
|
* @nr: Bit to set
|
|
* @addr: Address to count from
|
|
*
|
|
* This operation is atomic and cannot be reordered.
|
|
* It may be reordered on other architectures than x86.
|
|
* It also implies a memory barrier.
|
|
*/
|
|
static inline int test_and_set_bit(int nr, volatile unsigned long * addr)
|
|
{
|
|
int oldbit;
|
|
|
|
__asm__ __volatile__( LOCK_PREFIX
|
|
"btsl %2,%1\n\tsbbl %0,%0"
|
|
:"=r" (oldbit),"+m" (ADDR)
|
|
:"Ir" (nr) : "memory");
|
|
return oldbit;
|
|
}
|
|
|
|
/**
|
|
* __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 unsigned long * addr)
|
|
{
|
|
int oldbit;
|
|
|
|
__asm__(
|
|
"btsl %2,%1\n\tsbbl %0,%0"
|
|
:"=r" (oldbit),"+m" (ADDR)
|
|
:"Ir" (nr));
|
|
return oldbit;
|
|
}
|
|
|
|
/**
|
|
* test_and_clear_bit - Clear a bit and return its old value
|
|
* @nr: Bit to clear
|
|
* @addr: Address to count from
|
|
*
|
|
* This operation is atomic and cannot be reordered.
|
|
* It can be reorderdered on other architectures other than x86.
|
|
* It also implies a memory barrier.
|
|
*/
|
|
static inline int test_and_clear_bit(int nr, volatile unsigned long * addr)
|
|
{
|
|
int oldbit;
|
|
|
|
__asm__ __volatile__( LOCK_PREFIX
|
|
"btrl %2,%1\n\tsbbl %0,%0"
|
|
:"=r" (oldbit),"+m" (ADDR)
|
|
:"Ir" (nr) : "memory");
|
|
return oldbit;
|
|
}
|
|
|
|
/**
|
|
* __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 unsigned long *addr)
|
|
{
|
|
int oldbit;
|
|
|
|
__asm__(
|
|
"btrl %2,%1\n\tsbbl %0,%0"
|
|
:"=r" (oldbit),"+m" (ADDR)
|
|
:"Ir" (nr));
|
|
return oldbit;
|
|
}
|
|
|
|
/* WARNING: non atomic and it can be reordered! */
|
|
static inline int __test_and_change_bit(int nr, volatile unsigned long *addr)
|
|
{
|
|
int oldbit;
|
|
|
|
__asm__ __volatile__(
|
|
"btcl %2,%1\n\tsbbl %0,%0"
|
|
:"=r" (oldbit),"+m" (ADDR)
|
|
:"Ir" (nr) : "memory");
|
|
return oldbit;
|
|
}
|
|
|
|
/**
|
|
* test_and_change_bit - Change a bit and return its old value
|
|
* @nr: Bit to change
|
|
* @addr: Address to count from
|
|
*
|
|
* This operation is atomic and cannot be reordered.
|
|
* It also implies a memory barrier.
|
|
*/
|
|
static inline int test_and_change_bit(int nr, volatile unsigned long* addr)
|
|
{
|
|
int oldbit;
|
|
|
|
__asm__ __volatile__( LOCK_PREFIX
|
|
"btcl %2,%1\n\tsbbl %0,%0"
|
|
:"=r" (oldbit),"+m" (ADDR)
|
|
:"Ir" (nr) : "memory");
|
|
return oldbit;
|
|
}
|
|
|
|
#if 0 /* Fool kernel-doc since it doesn't do macros yet */
|
|
/**
|
|
* test_bit - Determine whether a bit is set
|
|
* @nr: bit number to test
|
|
* @addr: Address to start counting from
|
|
*/
|
|
static int test_bit(int nr, const volatile void * addr);
|
|
#endif
|
|
|
|
static __always_inline int constant_test_bit(int nr, const volatile unsigned long *addr)
|
|
{
|
|
return ((1UL << (nr & 31)) & (addr[nr >> 5])) != 0;
|
|
}
|
|
|
|
static inline int variable_test_bit(int nr, const volatile unsigned long * addr)
|
|
{
|
|
int oldbit;
|
|
|
|
__asm__ __volatile__(
|
|
"btl %2,%1\n\tsbbl %0,%0"
|
|
:"=r" (oldbit)
|
|
:"m" (ADDR),"Ir" (nr));
|
|
return oldbit;
|
|
}
|
|
|
|
#define test_bit(nr,addr) \
|
|
(__builtin_constant_p(nr) ? \
|
|
constant_test_bit((nr),(addr)) : \
|
|
variable_test_bit((nr),(addr)))
|
|
|
|
#undef ADDR
|
|
|
|
/**
|
|
* find_first_zero_bit - find the first zero 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 zero bit, not the number of the byte
|
|
* containing a bit.
|
|
*/
|
|
static inline int find_first_zero_bit(const unsigned long *addr, unsigned size)
|
|
{
|
|
int d0, d1, d2;
|
|
int res;
|
|
|
|
if (!size)
|
|
return 0;
|
|
/* This looks at memory. Mark it volatile to tell gcc not to move it around */
|
|
__asm__ __volatile__(
|
|
"movl $-1,%%eax\n\t"
|
|
"xorl %%edx,%%edx\n\t"
|
|
"repe; scasl\n\t"
|
|
"je 1f\n\t"
|
|
"xorl -4(%%edi),%%eax\n\t"
|
|
"subl $4,%%edi\n\t"
|
|
"bsfl %%eax,%%edx\n"
|
|
"1:\tsubl %%ebx,%%edi\n\t"
|
|
"shll $3,%%edi\n\t"
|
|
"addl %%edi,%%edx"
|
|
:"=d" (res), "=&c" (d0), "=&D" (d1), "=&a" (d2)
|
|
:"1" ((size + 31) >> 5), "2" (addr), "b" (addr) : "memory");
|
|
return res;
|
|
}
|
|
|
|
/**
|
|
* find_next_zero_bit - find the first zero bit in a memory region
|
|
* @addr: The address to base the search on
|
|
* @offset: The bitnumber to start searching at
|
|
* @size: The maximum size to search
|
|
*/
|
|
int find_next_zero_bit(const unsigned long *addr, int size, int offset);
|
|
|
|
/**
|
|
* __ffs - find first bit in word.
|
|
* @word: The word to search
|
|
*
|
|
* Undefined if no bit exists, so code should check against 0 first.
|
|
*/
|
|
static inline unsigned long __ffs(unsigned long word)
|
|
{
|
|
__asm__("bsfl %1,%0"
|
|
:"=r" (word)
|
|
:"rm" (word));
|
|
return word;
|
|
}
|
|
|
|
/**
|
|
* 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, not the number of the byte
|
|
* containing a bit.
|
|
*/
|
|
static inline unsigned find_first_bit(const unsigned long *addr, unsigned size)
|
|
{
|
|
unsigned x = 0;
|
|
|
|
while (x < size) {
|
|
unsigned long val = *addr++;
|
|
if (val)
|
|
return __ffs(val) + x;
|
|
x += (sizeof(*addr)<<3);
|
|
}
|
|
return x;
|
|
}
|
|
|
|
/**
|
|
* find_next_bit - find the first set bit in a memory region
|
|
* @addr: The address to base the search on
|
|
* @offset: The bitnumber to start searching at
|
|
* @size: The maximum size to search
|
|
*/
|
|
int find_next_bit(const unsigned long *addr, int size, int offset);
|
|
|
|
/**
|
|
* 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)
|
|
{
|
|
__asm__("bsfl %1,%0"
|
|
:"=r" (word)
|
|
:"r" (~word));
|
|
return word;
|
|
}
|
|
|
|
#ifdef __KERNEL__
|
|
|
|
#include <asm-generic/bitops/sched.h>
|
|
|
|
/**
|
|
* ffs - find first bit set
|
|
* @x: the word to search
|
|
*
|
|
* This is defined the same way as
|
|
* the libc and compiler builtin ffs routines, therefore
|
|
* differs in spirit from the above ffz() (man ffs).
|
|
*/
|
|
static inline int ffs(int x)
|
|
{
|
|
int r;
|
|
|
|
__asm__("bsfl %1,%0\n\t"
|
|
"jnz 1f\n\t"
|
|
"movl $-1,%0\n"
|
|
"1:" : "=r" (r) : "rm" (x));
|
|
return r+1;
|
|
}
|
|
|
|
/**
|
|
* fls - find last bit set
|
|
* @x: the word to search
|
|
*
|
|
* This is defined the same way as ffs().
|
|
*/
|
|
static inline int fls(int x)
|
|
{
|
|
int r;
|
|
|
|
__asm__("bsrl %1,%0\n\t"
|
|
"jnz 1f\n\t"
|
|
"movl $-1,%0\n"
|
|
"1:" : "=r" (r) : "rm" (x));
|
|
return r+1;
|
|
}
|
|
|
|
#include <asm-generic/bitops/hweight.h>
|
|
|
|
#endif /* __KERNEL__ */
|
|
|
|
#include <asm-generic/bitops/fls64.h>
|
|
|
|
#ifdef __KERNEL__
|
|
|
|
#include <asm-generic/bitops/ext2-non-atomic.h>
|
|
|
|
#define ext2_set_bit_atomic(lock,nr,addr) \
|
|
test_and_set_bit((nr),(unsigned long*)addr)
|
|
#define ext2_clear_bit_atomic(lock,nr, addr) \
|
|
test_and_clear_bit((nr),(unsigned long*)addr)
|
|
|
|
#include <asm-generic/bitops/minix.h>
|
|
|
|
#endif /* __KERNEL__ */
|
|
|
|
#endif /* _I386_BITOPS_H */
|