i2c: Fix sparse warning in i2c.h

[linux-2.6/sactl.git] / include / asm-i386 / bitops.h

#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 */