리눅스 커널의 include/asm-x86/bitops.h의 주요 함수를 Visual C++에서 컴파일 할 수 있도록 만들어 보았습니다.
#ifndef _I386_BITOPS_H
#define _I386_BITOPS_H
/*
* Copyright 1992, Linus Torvalds.
* Copyright 2008, Lee Jae-Hong (pyrasis)
*/
#include <linux/compiler.h>
#define inline __inline
/**
* 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 writting 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
{
mov eax, addr
mov ecx, nr
lock bts dword ptr [eax], ecx
}
}
/**
* 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
{
mov eax, addr
mov ecx, nr
lock btr dword ptr [eax], ecx
}
}
/**
* 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
{
mov eax, addr
mov ecx, nr
lock btc dword ptr [eax], ecx
}
}
/**
* 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
{
mov edx, addr
mov eax, nr
lock bts dword ptr [edx], eax
sbb eax, eax
mov oldbit, eax
}
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
{
mov edx, addr
mov eax, nr
lock btr dword ptr [edx], eax
sbb eax, eax
mov oldbit, eax
}
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
{
mov edx, addr
mov eax, nr
lock btc dword ptr [edx], eax
sbb eax, eax
mov oldbit, eax
}
return oldbit;
}
/**
* __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
{
bsf eax, [_word]
mov _word, eax
}
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)
{
int x = ~word;
__asm
{
bsf eax, [x]
}
}
/**
* 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)
{
__asm
{
bsf eax, [x]
jnz L1
mov eax, -1
L1:
inc eax
}
}
#endif /* _I386_BITOPS_H */
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