count_zeros.h

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/* Count leading and trailing zeros functions
 *
 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */

#ifndef _ASM_GENERIC_BITOPS_COUNT_ZEROS_H_
#define _ASM_GENERIC_BITOPS_COUNT_ZEROS_H_

#include <asm/bitops.h>

static inline int count_leading_zeros(unsigned long x)
{
    if (sizeof(x) == 4)
        return BITS_PER_LONG - fls(x);
    else
        return BITS_PER_LONG - fls64(x);
}

#define COUNT_LEADING_ZEROS_0 BITS_PER_LONG

static inline int count_trailing_zeros(unsigned long x)
{
#define COUNT_TRAILING_ZEROS_0 (-1)

    if (sizeof(x) == 4)
        return ffs(x);
    else
        return (x != 0) ? __ffs(x) : COUNT_TRAILING_ZEROS_0;
}

#endif /* _ASM_GENERIC_BITOPS_COUNT_ZEROS_H_ */