/* find_next_bit.c: fallback find next bit implementation * * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * * 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; either version * 2 of the License, or (at your option) any later version. */ #include <linux/bitops.h>#include <linux/module.h>#include <asm/types.h>#include <asm/byteorder.h> #define BITOP_WORD(nr)		((nr) / BITS_PER_LONG) /** * find_next_bit - find the next set bit in a memory region * @addr: The address to base the search on * @offset: The bitnumber to start searching at * @size: The maximum size to search */unsigned long find_next_bit(const unsigned long *addr, unsigned long size,		unsigned long offset){	const unsigned long *p = addr + BITOP_WORD(offset);	unsigned long result = offset & ~(BITS_PER_LONG-1);	unsigned long tmp; 	if (offset >= size)		return size;	size -= result;	offset %= BITS_PER_LONG;	if (offset) {		tmp = *(p++);		tmp &= (~0UL << offset);		if (size < BITS_PER_LONG)			goto found_first;		if (tmp)			goto found_middle;		size -= BITS_PER_LONG;		result += BITS_PER_LONG;	}	while (size & ~(BITS_PER_LONG-1)) {		if ((tmp = *(p++)))			goto found_middle;		result += BITS_PER_LONG;		size -= BITS_PER_LONG;	}	if (!size)		return result;	tmp = *p; found_first:	tmp &= (~0UL >> (BITS_PER_LONG - size));	if (tmp == 0UL)		/* Are any bits set? */		return result + size;	/* Nope. */found_middle:	return result + __ffs(tmp);} EXPORT_SYMBOL(find_next_bit); /* * This implementation of find_{first,next}_zero_bit was stolen from * Linus' asm-alpha/bitops.h. */unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size,		unsigned long offset){	const unsigned long *p = addr + BITOP_WORD(offset);	unsigned long result = offset & ~(BITS_PER_LONG-1);	unsigned long tmp; 	if (offset >= size)		return size;	size -= result;	offset %= BITS_PER_LONG;	if (offset) {		tmp = *(p++);		tmp |= ~0UL >> (BITS_PER_LONG - offset);		if (size < BITS_PER_LONG)			goto found_first;		if (~tmp)			goto found_middle;		size -= BITS_PER_LONG;		result += BITS_PER_LONG;	}	while (size & ~(BITS_PER_LONG-1)) {		if (~(tmp = *(p++)))			goto found_middle;		result += BITS_PER_LONG;		size -= BITS_PER_LONG;	}	if (!size)		return result;	tmp = *p; found_first:	tmp |= ~0UL << size;	if (tmp == ~0UL)	/* Are any bits zero? */		return result + size;	/* Nope. */found_middle:	return result + ffz(tmp);} EXPORT_SYMBOL(find_next_zero_bit); #ifdef __BIG_ENDIAN /* include/linux/byteorder does not support "unsigned long" type */static inline unsigned long ext2_swabp(const unsigned long * x){#if BITS_PER_LONG == 64	return (unsigned long) __swab64p((u64 *) x);#elif BITS_PER_LONG == 32	return (unsigned long) __swab32p((u32 *) x);#else#error BITS_PER_LONG not defined#endif} /* include/linux/byteorder doesn't support "unsigned long" type */static inline unsigned long ext2_swab(const unsigned long y){#if BITS_PER_LONG == 64	return (unsigned long) __swab64((u64) y);#elif BITS_PER_LONG == 32	return (unsigned long) __swab32((u32) y);#else#error BITS_PER_LONG not defined#endif} unsigned long generic_find_next_zero_le_bit(const unsigned long *addr, unsigned		long size, unsigned long offset){	const unsigned long *p = addr + BITOP_WORD(offset);	unsigned long result = offset & ~(BITS_PER_LONG - 1);	unsigned long tmp; 	if (offset >= size)		return size;	size -= result;	offset &= (BITS_PER_LONG - 1UL);	if (offset) {		tmp = ext2_swabp(p++);		tmp |= (~0UL >> (BITS_PER_LONG - offset));		if (size < BITS_PER_LONG)			goto found_first;		if (~tmp)			goto found_middle;		size -= BITS_PER_LONG;		result += BITS_PER_LONG;	} 	while (size & ~(BITS_PER_LONG - 1)) {		if (~(tmp = *(p++)))			goto found_middle_swap;		result += BITS_PER_LONG;		size -= BITS_PER_LONG;	}	if (!size)		return result;	tmp = ext2_swabp(p);found_first:	tmp |= ~0UL << size;	if (tmp == ~0UL)	/* Are any bits zero? */		return result + size; /* Nope. Skip ffz */found_middle:	return result + ffz(tmp); found_middle_swap:	return result + ffz(ext2_swab(tmp));} EXPORT_SYMBOL(generic_find_next_zero_le_bit); #endif /* __BIG_ENDIAN */