linux/lib/find_bit.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* bit search implementation
 *
 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([email protected])
 *
 * Copyright (C) 2008 IBM Corporation
 * 'find_last_bit' is written by Rusty Russell <[email protected]>
 * (Inspired by David Howell's find_next_bit implementation)
 *
 * Rewritten by Yury Norov <[email protected]> to decrease
 * size and improve performance, 2015.
 */

#include <linux/bitops.h>
#include <linux/bitmap.h>
#include <linux/export.h>
#include <linux/math.h>
#include <linux/minmax.h>
#include <linux/swab.h>

/*
 * Common helper for find_bit() function family
 * @FETCH: The expression that fetches and pre-processes each word of bitmap(s)
 * @MUNGE: The expression that post-processes a word containing found bit (may be empty)
 * @size: The bitmap size in bits
 */
#define FIND_FIRST_BIT(FETCH, MUNGE, size) …

/*
 * Common helper for find_next_bit() function family
 * @FETCH: The expression that fetches and pre-processes each word of bitmap(s)
 * @MUNGE: The expression that post-processes a word containing found bit (may be empty)
 * @size: The bitmap size in bits
 * @start: The bitnumber to start searching at
 */
#define FIND_NEXT_BIT(FETCH, MUNGE, size, start) …

#define FIND_NTH_BIT(FETCH, size, num) …

#ifndef find_first_bit
/*
 * Find the first set bit in a memory region.
 */
unsigned long _find_first_bit(const unsigned long *addr, unsigned long size)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef find_first_and_bit
/*
 * Find the first set bit in two memory regions.
 */
unsigned long _find_first_and_bit(const unsigned long *addr1,
				  const unsigned long *addr2,
				  unsigned long size)
{ … }
EXPORT_SYMBOL(…);
#endif

/*
 * Find the first set bit in three memory regions.
 */
unsigned long _find_first_and_and_bit(const unsigned long *addr1,
				      const unsigned long *addr2,
				      const unsigned long *addr3,
				      unsigned long size)
{ … }
EXPORT_SYMBOL(…);

#ifndef find_first_zero_bit
/*
 * Find the first cleared bit in a memory region.
 */
unsigned long _find_first_zero_bit(const unsigned long *addr, unsigned long size)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef find_next_bit
unsigned long _find_next_bit(const unsigned long *addr, unsigned long nbits, unsigned long start)
{ … }
EXPORT_SYMBOL(…);
#endif

unsigned long __find_nth_bit(const unsigned long *addr, unsigned long size, unsigned long n)
{ … }
EXPORT_SYMBOL(…);

unsigned long __find_nth_and_bit(const unsigned long *addr1, const unsigned long *addr2,
				 unsigned long size, unsigned long n)
{ … }
EXPORT_SYMBOL(…);

unsigned long __find_nth_andnot_bit(const unsigned long *addr1, const unsigned long *addr2,
				 unsigned long size, unsigned long n)
{ … }
EXPORT_SYMBOL(…);

unsigned long __find_nth_and_andnot_bit(const unsigned long *addr1,
					const unsigned long *addr2,
					const unsigned long *addr3,
					unsigned long size, unsigned long n)
{ … }
EXPORT_SYMBOL(…);

#ifndef find_next_and_bit
unsigned long _find_next_and_bit(const unsigned long *addr1, const unsigned long *addr2,
					unsigned long nbits, unsigned long start)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef find_next_andnot_bit
unsigned long _find_next_andnot_bit(const unsigned long *addr1, const unsigned long *addr2,
					unsigned long nbits, unsigned long start)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef find_next_or_bit
unsigned long _find_next_or_bit(const unsigned long *addr1, const unsigned long *addr2,
					unsigned long nbits, unsigned long start)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef find_next_zero_bit
unsigned long _find_next_zero_bit(const unsigned long *addr, unsigned long nbits,
					 unsigned long start)
{ … }
EXPORT_SYMBOL(…);
#endif

#ifndef find_last_bit
unsigned long _find_last_bit(const unsigned long *addr, unsigned long size)
{ … }
EXPORT_SYMBOL(…);
#endif

unsigned long find_next_clump8(unsigned long *clump, const unsigned long *addr,
			       unsigned long size, unsigned long offset)
{ … }
EXPORT_SYMBOL(…);

#ifdef __BIG_ENDIAN

#ifndef find_first_zero_bit_le
/*
 * Find the first cleared bit in an LE memory region.
 */
unsigned long _find_first_zero_bit_le(const unsigned long *addr, unsigned long size)
{
	return FIND_FIRST_BIT(~addr[idx], swab, size);
}
EXPORT_SYMBOL(_find_first_zero_bit_le);

#endif

#ifndef find_next_zero_bit_le
unsigned long _find_next_zero_bit_le(const unsigned long *addr,
					unsigned long size, unsigned long offset)
{
	return FIND_NEXT_BIT(~addr[idx], swab, size, offset);
}
EXPORT_SYMBOL(_find_next_zero_bit_le);
#endif

#ifndef find_next_bit_le
unsigned long _find_next_bit_le(const unsigned long *addr,
				unsigned long size, unsigned long offset)
{
	return FIND_NEXT_BIT(addr[idx], swab, size, offset);
}
EXPORT_SYMBOL(_find_next_bit_le);

#endif

#endif /* __BIG_ENDIAN */