bitops_64.h

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/*
 * Copyright 2011 Tilera Corporation. All Rights Reserved.
 *
 *   This program is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU General Public License
 *   as published by the Free Software Foundation, version 2.
 *
 *   This program is distributed in the hope that it will be useful, but
 *   WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 *   NON INFRINGEMENT.  See the GNU General Public License for
 *   more details.
 */

#ifndef _ASM_TILE_BITOPS_64_H
#define _ASM_TILE_BITOPS_64_H

#include <linux/compiler.h>
#include <linux/atomic.h>

/* See <asm/bitops.h> for API comments. */

static inline void set_bit(unsigned nr, volatile unsigned long *addr)
{
    unsigned long mask = (1UL << (nr % BITS_PER_LONG));
    __insn_fetchor((void *)(addr + nr / BITS_PER_LONG), mask);
}

static inline void clear_bit(unsigned nr, volatile unsigned long *addr)
{
    unsigned long mask = (1UL << (nr % BITS_PER_LONG));
    __insn_fetchand((void *)(addr + nr / BITS_PER_LONG), ~mask);
}

#define smp_mb__before_clear_bit()  smp_mb()
#define smp_mb__after_clear_bit()   smp_mb()


static inline void change_bit(unsigned nr, volatile unsigned long *addr)
{
    unsigned long mask = (1UL << (nr % BITS_PER_LONG));
    unsigned long guess, oldval;
    addr += nr / BITS_PER_LONG;
    oldval = *addr;
    do {
        guess = oldval;
        oldval = atomic64_cmpxchg((atomic64_t *)addr,
                      guess, guess ^ mask);
    } while (guess != oldval);
}


/*
 * The test_and_xxx_bit() routines require a memory fence before we
 * start the operation, and after the operation completes.  We use
 * smp_mb() before, and rely on the "!= 0" comparison, plus a compiler
 * barrier(), to block until the atomic op is complete.
 */

static inline int test_and_set_bit(unsigned nr, volatile unsigned long *addr)
{
    int val;
    unsigned long mask = (1UL << (nr % BITS_PER_LONG));
    smp_mb();  /* barrier for proper semantics */
    val = (__insn_fetchor((void *)(addr + nr / BITS_PER_LONG), mask)
           & mask) != 0;
    barrier();
    return val;
}


static inline int test_and_clear_bit(unsigned nr, volatile unsigned long *addr)
{
    int val;
    unsigned long mask = (1UL << (nr % BITS_PER_LONG));
    smp_mb();  /* barrier for proper semantics */
    val = (__insn_fetchand((void *)(addr + nr / BITS_PER_LONG), ~mask)
           & mask) != 0;
    barrier();
    return val;
}


static inline int test_and_change_bit(unsigned nr,
                      volatile unsigned long *addr)
{
    unsigned long mask = (1UL << (nr % BITS_PER_LONG));
    unsigned long guess, oldval;
    addr += nr / BITS_PER_LONG;
    oldval = *addr;
    do {
        guess = oldval;
        oldval = atomic64_cmpxchg((atomic64_t *)addr,
                      guess, guess ^ mask);
    } while (guess != oldval);
    return (oldval & mask) != 0;
}

#include <asm-generic/bitops/ext2-atomic-setbit.h>

#endif /* _ASM_TILE_BITOPS_64_H */