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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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C
1234567891011121314151617181920212223242526272829303132333435363738394041424344454647/* SPDX-License-Identifier: GPL-2.0-or-later *//* Count leading and trailing zeros functions * * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) */
#ifndef _LINUX_BITOPS_COUNT_ZEROS_H_#define _LINUX_BITOPS_COUNT_ZEROS_H_
#include <asm/bitops.h>
/** * count_leading_zeros - Count the number of zeros from the MSB back * @x: The value * * Count the number of leading zeros from the MSB going towards the LSB in @x. * * If the MSB of @x is set, the result is 0. * If only the LSB of @x is set, then the result is BITS_PER_LONG-1. * If @x is 0 then the result is BITS_PER_LONG. */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);}
/** * count_trailing_zeros - Count the number of zeros from the LSB forwards * @x: The value * * Count the number of trailing zeros from the LSB going towards the MSB in @x. * * If the LSB of @x is set, the result is 0. * If only the MSB of @x is set, then the result is BITS_PER_LONG-1. * If @x is 0 then the result is BITS_PER_LONG. */static inline int count_trailing_zeros(unsigned long x){ return x ? __ffs(x) : BITS_PER_LONG;}
#endif /* _LINUX_BITOPS_COUNT_ZEROS_H_ */