cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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count_zeros.h (1453B)

      1/* SPDX-License-Identifier: GPL-2.0-or-later */
      2/* Count leading and trailing zeros functions
      3 *
      4 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
      5 * Written by David Howells (dhowells@redhat.com)
      6 */
      7
      8#ifndef _LINUX_BITOPS_COUNT_ZEROS_H_
      9#define _LINUX_BITOPS_COUNT_ZEROS_H_
     10
     11#include <asm/bitops.h>
     12
     13/**
     14 * count_leading_zeros - Count the number of zeros from the MSB back
     15 * @x: The value
     16 *
     17 * Count the number of leading zeros from the MSB going towards the LSB in @x.
     18 *
     19 * If the MSB of @x is set, the result is 0.
     20 * If only the LSB of @x is set, then the result is BITS_PER_LONG-1.
     21 * If @x is 0 then the result is COUNT_LEADING_ZEROS_0.
     22 */
     23static inline int count_leading_zeros(unsigned long x)
     24{
     25	if (sizeof(x) == 4)
     26		return BITS_PER_LONG - fls(x);
     27	else
     28		return BITS_PER_LONG - fls64(x);
     29}
     30
     31#define COUNT_LEADING_ZEROS_0 BITS_PER_LONG
     32
     33/**
     34 * count_trailing_zeros - Count the number of zeros from the LSB forwards
     35 * @x: The value
     36 *
     37 * Count the number of trailing zeros from the LSB going towards the MSB in @x.
     38 *
     39 * If the LSB of @x is set, the result is 0.
     40 * If only the MSB of @x is set, then the result is BITS_PER_LONG-1.
     41 * If @x is 0 then the result is COUNT_TRAILING_ZEROS_0.
     42 */
     43static inline int count_trailing_zeros(unsigned long x)
     44{
     45#define COUNT_TRAILING_ZEROS_0 (-1)
     46
     47	if (sizeof(x) == 4)
     48		return ffs(x);
     49	else
     50		return (x != 0) ? __ffs(x) : COUNT_TRAILING_ZEROS_0;
     51}
     52
     53#endif /* _LINUX_BITOPS_COUNT_ZEROS_H_ */