linux/include/asm-mips/bitops.h

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (c) 1994 - 1997, 1999, 2000  Ralf Baechle (ralf@gnu.org)
 * Copyright (c) 1999, 2000  Silicon Graphics, Inc.
 */
#ifndef _ASM_BITOPS_H
#define _ASM_BITOPS_H

#include <linux/config.h>
#include <linux/compiler.h>
#include <linux/types.h>
#include <asm/bug.h>
#include <asm/byteorder.h>		/* sigh ... */
#include <asm/cpu-features.h>

#if (_MIPS_SZLONG == 32)
#define SZLONG_LOG 5
#define SZLONG_MASK 31UL
#define __LL		"ll	"
#define __SC		"sc	"
#define cpu_to_lelongp(x) cpu_to_le32p((__u32 *) (x))
#elif (_MIPS_SZLONG == 64)
#define SZLONG_LOG 6
#define SZLONG_MASK 63UL
#define __LL		"lld	"
#define __SC		"scd	"
#define cpu_to_lelongp(x) cpu_to_le64p((__u64 *) (x))
#endif

#ifdef __KERNEL__

#include <asm/interrupt.h>
#include <asm/sgidefs.h>
#include <asm/war.h>

/*
 * clear_bit() doesn't provide any barrier for the compiler.
 */
#define smp_mb__before_clear_bit()	smp_mb()
#define smp_mb__after_clear_bit()	smp_mb()

/*
 * Only disable interrupt for kernel mode stuff to keep usermode stuff
 * that dares to use kernel include files alive.
 */

#define __bi_flags			unsigned long flags
#define __bi_local_irq_save(x)		local_irq_save(x)
#define __bi_local_irq_restore(x)	local_irq_restore(x)
#else
#define __bi_flags
#define __bi_local_irq_save(x)
#define __bi_local_irq_restore(x)
#endif /* __KERNEL__ */

/*
 * set_bit - Atomically set a bit in memory
 * @nr: the bit to set
 * @addr: the address to start counting from
 *
 * This function is atomic and may not be reordered.  See __set_bit()
 * if you do not require the atomic guarantees.
 * Note that @nr may be almost arbitrarily large; this function is not
 * restricted to acting on a single-word quantity.
 */
static inline void set_bit(unsigned long nr, volatile unsigned long *addr)
{
	unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
	unsigned long temp;

	if (cpu_has_llsc && R10000_LLSC_WAR) {
		__asm__ __volatile__(
		"	.set	mips3					\n"
		"1:	" __LL "%0, %1			# set_bit	\n"
		"	or	%0, %2					\n"
		"	" __SC	"%0, %1					\n"
		"	beqzl	%0, 1b					\n"
		"	.set	mips0					\n"
		: "=&r" (temp), "=m" (*m)
		: "ir" (1UL << (nr & SZLONG_MASK)), "m" (*m));
	} else if (cpu_has_llsc) {
		__asm__ __volatile__(
		"	.set	mips3					\n"
		"1:	" __LL "%0, %1			# set_bit	\n"
		"	or	%0, %2					\n"
		"	" __SC	"%0, %1					\n"
		"	beqz	%0, 1b					\n"
		"	.set	mips0					\n"
		: "=&r" (temp), "=m" (*m)
		: "ir" (1UL << (nr & SZLONG_MASK)), "m" (*m));
	} else {
		volatile unsigned long *a = addr;
		unsigned long mask;
		__bi_flags;

		a += nr >> SZLONG_LOG;
		mask = 1UL << (nr & SZLONG_MASK);
		__bi_local_irq_save(flags);
		*a |= mask;
		__bi_local_irq_restore(flags);
	}
}

/*
 * __set_bit - Set a bit in memory
 * @nr: the bit to set
 * @addr: the address to start counting from
 *
 * Unlike set_bit(), this function is non-atomic and may be reordered.
 * If it's called on the same region of memory simultaneously, the effect
 * may be that only one operation succeeds.
 */
static inline void __set_bit(unsigned long nr, volatile unsigned long * addr)
{
	unsigned long * m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);

	*m |= 1UL << (nr & SZLONG_MASK);
}

/*
 * clear_bit - Clears a bit in memory
 * @nr: Bit to clear
 * @addr: Address to start counting from
 *
 * clear_bit() is atomic and may not be reordered.  However, it does
 * not contain a memory barrier, so if it is used for locking purposes,
 * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit()
 * in order to ensure changes are visible on other processors.
 */
static inline void clear_bit(unsigned long nr, volatile unsigned long *addr)
{
	unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
	unsigned long temp;

	if (cpu_has_llsc && R10000_LLSC_WAR) {
		__asm__ __volatile__(
		"	.set	mips3					\n"
		"1:	" __LL "%0, %1			# clear_bit	\n"
		"	and	%0, %2					\n"
		"	" __SC "%0, %1					\n"
		"	beqzl	%0, 1b					\n"
		"	.set	mips0					\n"
		: "=&r" (temp), "=m" (*m)
		: "ir" (~(1UL << (nr & SZLONG_MASK))), "m" (*m));
	} else if (cpu_has_llsc) {
		__asm__ __volatile__(
		"	.set	mips3					\n"
		"1:	" __LL "%0, %1			# clear_bit	\n"
		"	and	%0, %2					\n"
		"	" __SC "%0, %1					\n"
		"	beqz	%0, 1b					\n"
		"	.set	mips0					\n"
		: "=&r" (temp), "=m" (*m)
		: "ir" (~(1UL << (nr & SZLONG_MASK))), "m" (*m));
	} else {
		volatile unsigned long *a = addr;
		unsigned long mask;
		__bi_flags;

		a += nr >> SZLONG_LOG;
		mask = 1UL << (nr & SZLONG_MASK);
		__bi_local_irq_save(flags);
		*a &= ~mask;
		__bi_local_irq_restore(flags);
	}
}

/*
 * __clear_bit - Clears a bit in memory
 * @nr: Bit to clear
 * @addr: Address to start counting from
 *
 * Unlike clear_bit(), this function is non-atomic and may be reordered.
 * If it's called on the same region of memory simultaneously, the effect
 * may be that only one operation succeeds.
 */
static inline void __clear_bit(unsigned long nr, volatile unsigned long * addr)
{
	unsigned long * m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);

	*m &= ~(1UL << (nr & SZLONG_MASK));
}

/*
 * change_bit - Toggle a bit in memory
 * @nr: Bit to change
 * @addr: Address to start counting from
 *
 * change_bit() is atomic and may not be reordered.
 * Note that @nr may be almost arbitrarily large; this function is not
 * restricted to acting on a single-word quantity.
 */
static inline void change_bit(unsigned long nr, volatile unsigned long *addr)
{
	if (cpu_has_llsc && R10000_LLSC_WAR) {
		unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
		unsigned long temp;

		__asm__ __volatile__(
		"	.set	mips3				\n"
		"1:	" __LL "%0, %1		# change_bit	\n"
		"	xor	%0, %2				\n"
		"	" __SC	"%0, %1				\n"
		"	beqzl	%0, 1b				\n"
		"	.set	mips0				\n"
		: "=&r" (temp), "=m" (*m)
		: "ir" (1UL << (nr & SZLONG_MASK)), "m" (*m));
	} else if (cpu_has_llsc) {
		unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
		unsigned long temp;

		__asm__ __volatile__(
		"	.set	mips3				\n"
		"1:	" __LL "%0, %1		# change_bit	\n"
		"	xor	%0, %2				\n"
		"	" __SC	"%0, %1				\n"
		"	beqz	%0, 1b				\n"
		"	.set	mips0				\n"
		: "=&r" (temp), "=m" (*m)
		: "ir" (1UL << (nr & SZLONG_MASK)), "m" (*m));
	} else {
		volatile unsigned long *a = addr;
		unsigned long mask;
		__bi_flags;

		a += nr >> SZLONG_LOG;
		mask = 1UL << (nr & SZLONG_MASK);
		__bi_local_irq_save(flags);
		*a ^= mask;
		__bi_local_irq_restore(flags);
	}
}

/*
 * __change_bit - Toggle a bit in memory
 * @nr: the bit to change
 * @addr: the address to start counting from
 *
 * Unlike change_bit(), this function is non-atomic and may be reordered.
 * If it's called on the same region of memory simultaneously, the effect
 * may be that only one operation succeeds.
 */
static inline void __change_bit(unsigned long nr, volatile unsigned long * addr)
{
	unsigned long * m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);

	*m ^= 1UL << (nr & SZLONG_MASK);
}

/*
 * test_and_set_bit - Set a bit and return its old value
 * @nr: Bit to set
 * @addr: Address to count from
 *
 * This operation is atomic and cannot be reordered.
 * It also implies a memory barrier.
 */
static inline int test_and_set_bit(unsigned long nr,
	volatile unsigned long *addr)
{
	if (cpu_has_llsc && R10000_LLSC_WAR) {
		unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
		unsigned long temp, res;

		__asm__ __volatile__(
		"	.set	mips3					\n"
		"1:	" __LL "%0, %1		# test_and_set_bit	\n"
		"	or	%2, %0, %3				\n"
		"	" __SC	"%2, %1					\n"
		"	beqzl	%2, 1b					\n"
		"	and	%2, %0, %3				\n"
#ifdef CONFIG_SMP
		"	sync						\n"
#endif
		"	.set	mips0					\n"
		: "=&r" (temp), "=m" (*m), "=&r" (res)
		: "r" (1UL << (nr & SZLONG_MASK)), "m" (*m)
		: "memory");

		return res != 0;
	} else if (cpu_has_llsc) {
		unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
		unsigned long temp, res;

		__asm__ __volatile__(
		"	.set	push					\n"
		"	.set	noreorder				\n"
		"	.set	mips3					\n"
		"1:	" __LL "%0, %1		# test_and_set_bit	\n"
		"	or	%2, %0, %3				\n"
		"	" __SC	"%2, %1					\n"
		"	beqz	%2, 1b					\n"
		"	 and	%2, %0, %3				\n"
#ifdef CONFIG_SMP
		"	sync						\n"
#endif
		"	.set	pop					\n"
		: "=&r" (temp), "=m" (*m), "=&r" (res)
		: "r" (1UL << (nr & SZLONG_MASK)), "m" (*m)
		: "memory");

		return res != 0;
	} else {
		volatile unsigned long *a = addr;
		unsigned long mask;
		int retval;
		__bi_flags;

		a += nr >> SZLONG_LOG;
		mask = 1UL << (nr & SZLONG_MASK);
		__bi_local_irq_save(flags);
		retval = (mask & *a) != 0;
		*a |= mask;
		__bi_local_irq_restore(flags);

		return retval;
	}
}

/*
 * __test_and_set_bit - Set a bit and return its old value
 * @nr: Bit to set
 * @addr: Address to count from
 *
 * This operation is non-atomic and can be reordered.
 * If two examples of this operation race, one can appear to succeed
 * but actually fail.  You must protect multiple accesses with a lock.
 */
static inline int __test_and_set_bit(unsigned long nr,
	volatile unsigned long *addr)
{
	volatile unsigned long *a = addr;
	unsigned long mask;
	int retval;

	a += nr >> SZLONG_LOG;
	mask = 1UL << (nr & SZLONG_MASK);
	retval = (mask & *a) != 0;
	*a |= mask;

	return retval;
}

/*
 * test_and_clear_bit - Clear a bit and return its old value
 * @nr: Bit to clear
 * @addr: Address to count from
 *
 * This operation is atomic and cannot be reordered.
 * It also implies a memory barrier.
 */
static inline int test_and_clear_bit(unsigned long nr,
	volatile unsigned long *addr)
{
	if (cpu_has_llsc && R10000_LLSC_WAR) {
		unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
		unsigned long temp, res;

		__asm__ __volatile__(
		"	.set	mips3					\n"
		"1:	" __LL	"%0, %1		# test_and_clear_bit	\n"
		"	or	%2, %0, %3				\n"
		"	xor	%2, %3					\n"
		"	" __SC 	"%2, %1					\n"
		"	beqzl	%2, 1b					\n"
		"	and	%2, %0, %3				\n"
#ifdef CONFIG_SMP
		"	sync						\n"
#endif
		"	.set	mips0					\n"
		: "=&r" (temp), "=m" (*m), "=&r" (res)
		: "r" (1UL << (nr & SZLONG_MASK)), "m" (*m)
		: "memory");

		return res != 0;
	} else if (cpu_has_llsc) {
		unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
		unsigned long temp, res;

		__asm__ __volatile__(
		"	.set	push					\n"
		"	.set	noreorder				\n"
		"	.set	mips3					\n"
		"1:	" __LL	"%0, %1		# test_and_clear_bit	\n"
		"	or	%2, %0, %3				\n"
		"	xor	%2, %3					\n"
		"	" __SC 	"%2, %1					\n"
		"	beqz	%2, 1b					\n"
		"	 and	%2, %0, %3				\n"
#ifdef CONFIG_SMP
		"	sync						\n"
#endif
		"	.set	pop					\n"
		: "=&r" (temp), "=m" (*m), "=&r" (res)
		: "r" (1UL << (nr & SZLONG_MASK)), "m" (*m)
		: "memory");

		return res != 0;
	} else {
		volatile unsigned long *a = addr;
		unsigned long mask;
		int retval;
		__bi_flags;

		a += nr >> SZLONG_LOG;
		mask = 1UL << (nr & SZLONG_MASK);
		__bi_local_irq_save(flags);
		retval = (mask & *a) != 0;
		*a &= ~mask;
		__bi_local_irq_restore(flags);

		return retval;
	}
}

/*
 * __test_and_clear_bit - Clear a bit and return its old value
 * @nr: Bit to clear
 * @addr: Address to count from
 *
 * This operation is non-atomic and can be reordered.
 * If two examples of this operation race, one can appear to succeed
 * but actually fail.  You must protect multiple accesses with a lock.
 */
static inline int __test_and_clear_bit(unsigned long nr,
	volatile unsigned long * addr)
{
	volatile unsigned long *a = addr;
	unsigned long mask;
	int retval;

	a += (nr >> SZLONG_LOG);
	mask = 1UL << (nr & SZLONG_MASK);
	retval = ((mask & *a) != 0);
	*a &= ~mask;

	return retval;
}

/*
 * test_and_change_bit - Change a bit and return its old value
 * @nr: Bit to change
 * @addr: Address to count from
 *
 * This operation is atomic and cannot be reordered.
 * It also implies a memory barrier.
 */
static inline int test_and_change_bit(unsigned long nr,
	volatile unsigned long *addr)
{
	if (cpu_has_llsc && R10000_LLSC_WAR) {
		unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
		unsigned long temp, res;

		__asm__ __volatile__(
		"	.set	mips3					\n"
		"1:	" __LL	"%0, %1		# test_and_change_bit	\n"
		"	xor	%2, %0, %3				\n"
		"	" __SC	"%2, %1					\n"
		"	beqzl	%2, 1b					\n"
		"	and	%2, %0, %3				\n"
#ifdef CONFIG_SMP
		"	sync						\n"
#endif
		"	.set	mips0					\n"
		: "=&r" (temp), "=m" (*m), "=&r" (res)
		: "r" (1UL << (nr & SZLONG_MASK)), "m" (*m)
		: "memory");

		return res != 0;
	} else if (cpu_has_llsc) {
		unsigned long *m = ((unsigned long *) addr) + (nr >> SZLONG_LOG);
		unsigned long temp, res;

		__asm__ __volatile__(
		"	.set	push					\n"
		"	.set	noreorder				\n"
		"	.set	mips3					\n"
		"1:	" __LL	"%0, %1		# test_and_change_bit	\n"
		"	xor	%2, %0, %3				\n"
		"	" __SC	"\t%2, %1				\n"
		"	beqz	%2, 1b					\n"
		"	 and	%2, %0, %3				\n"
#ifdef CONFIG_SMP
		"	sync						\n"
#endif
		"	.set	pop					\n"
		: "=&r" (temp), "=m" (*m), "=&r" (res)
		: "r" (1UL << (nr & SZLONG_MASK)), "m" (*m)
		: "memory");

		return res != 0;
	} else {
		volatile unsigned long *a = addr;
		unsigned long mask, retval;
		__bi_flags;

		a += nr >> SZLONG_LOG;
		mask = 1UL << (nr & SZLONG_MASK);
		__bi_local_irq_save(flags);
		retval = (mask & *a) != 0;
		*a ^= mask;
		__bi_local_irq_restore(flags);

		return retval;
	}
}

/*
 * __test_and_change_bit - Change a bit and return its old value
 * @nr: Bit to change
 * @addr: Address to count from
 *
 * This operation is non-atomic and can be reordered.
 * If two examples of this operation race, one can appear to succeed
 * but actually fail.  You must protect multiple accesses with a lock.
 */
static inline int __test_and_change_bit(unsigned long nr,
	volatile unsigned long *addr)
{
	volatile unsigned long *a = addr;
	unsigned long mask;
	int retval;

	a += (nr >> SZLONG_LOG);
	mask = 1UL << (nr & SZLONG_MASK);
	retval = ((mask & *a) != 0);
	*a ^= mask;

	return retval;
}

#undef __bi_flags
#undef __bi_local_irq_save
#undef __bi_local_irq_restore

/*
 * test_bit - Determine whether a bit is set
 * @nr: bit number to test
 * @addr: Address to start counting from
 */
static inline int test_bit(unsigned long nr, const volatile unsigned long *addr)
{
	return 1UL & (addr[nr >> SZLONG_LOG] >> (nr & SZLONG_MASK));
}

/*
 * Return the bit position (0..63) of the most significant 1 bit in a word
 * Returns -1 if no 1 bit exists
 */
static inline int __ilog2(unsigned long x)
{
	int lz;

	if (sizeof(x) == 4) {
		__asm__ (
		"	.set	push					\n"
		"	.set	mips32					\n"
		"	clz	%0, %1					\n"
		"	.set	pop					\n"
		: "=r" (lz)
		: "r" (x));

		return 31 - lz;
	}

	BUG_ON(sizeof(x) != 8);

	__asm__ (
	"	.set	push						\n"
	"	.set	mips64						\n"
	"	dclz	%0, %1						\n"
	"	.set	pop						\n"
	: "=r" (lz)
	: "r" (x));

	return 63 - lz;
}

/*
 * __ffs - find first bit in word.
 * @word: The word to search
 *
 * Returns 0..SZLONG-1
 * Undefined if no bit exists, so code should check against 0 first.
 */
static inline unsigned long __ffs(unsigned long word)
{
#if defined(CONFIG_CPU_MIPS32) || defined(CONFIG_CPU_MIPS64)
	return __ilog2(word & -word);
#else
	int b = 0, s;

#ifdef CONFIG_32BIT
	s = 16; if (word << 16 != 0) s = 0; b += s; word >>= s;
	s =  8; if (word << 24 != 0) s = 0; b += s; word >>= s;
	s =  4; if (word << 28 != 0) s = 0; b += s; word >>= s;
	s =  2; if (word << 30 != 0) s = 0; b += s; word >>= s;
	s =  1; if (word << 31 != 0) s = 0; b += s;

	return b;
#endif
#ifdef CONFIG_64BIT
	s = 32; if (word << 32 != 0) s = 0; b += s; word >>= s;
	s = 16; if (word << 48 != 0) s = 0; b += s; word >>= s;
	s =  8; if (word << 56 != 0) s = 0; b += s; word >>= s;
	s =  4; if (word << 60 != 0) s = 0; b += s; word >>= s;
	s =  2; if (word << 62 != 0) s = 0; b += s; word >>= s;
	s =  1; if (word << 63 != 0) s = 0; b += s;

	return b;
#endif
#endif
}

/*
 * ffs - find first bit set.
 * @word: The word to search
 *
 * Returns 1..SZLONG
 * Returns 0 if no bit exists
 */

static inline unsigned long ffs(unsigned long word)
{
	if (!word)
		return 0;

	return __ffs(word) + 1;
}

/*
 * ffz - find first zero in word.
 * @word: The word to search
 *
 * Undefined if no zero exists, so code should check against ~0UL first.
 */
static inline unsigned long ffz(unsigned long word)
{
	return __ffs (~word);
}

/*
 * flz - find last zero in word.
 * @word: The word to search
 *
 * Returns 0..SZLONG-1
 * Undefined if no zero exists, so code should check against ~0UL first.
 */
static inline unsigned long flz(unsigned long word)
{
#if defined(CONFIG_CPU_MIPS32) || defined(CONFIG_CPU_MIPS64)
	return __ilog2(~word);
#else
#ifdef CONFIG_32BIT
	int r = 31, s;
	word = ~word;
	s = 16; if ((word & 0xffff0000)) s = 0; r -= s; word <<= s;
	s = 8;  if ((word & 0xff000000)) s = 0; r -= s; word <<= s;
	s = 4;  if ((word & 0xf0000000)) s = 0; r -= s; word <<= s;
	s = 2;  if ((word & 0xc0000000)) s = 0; r -= s; word <<= s;
	s = 1;  if ((word & 0x80000000)) s = 0; r -= s;

	return r;
#endif
#ifdef CONFIG_64BIT
	int r = 63, s;
	word = ~word;
	s = 32; if ((word & 0xffffffff00000000UL)) s = 0; r -= s; word <<= s;
	s = 16; if ((word & 0xffff000000000000UL)) s = 0; r -= s; word <<= s;
	s = 8;  if ((word & 0xff00000000000000UL)) s = 0; r -= s; word <<= s;
	s = 4;  if ((word & 0xf000000000000000UL)) s = 0; r -= s; word <<= s;
	s = 2;  if ((word & 0xc000000000000000UL)) s = 0; r -= s; word <<= s;
	s = 1;  if ((word & 0x8000000000000000UL)) s = 0; r -= s;

	return r;
#endif
#endif
}

/*
 * fls - find last bit set.
 * @word: The word to search
 *
 * Returns 1..SZLONG
 * Returns 0 if no bit exists
 */
static inline unsigned long fls(unsigned long word)
{
	if (word == 0)
		return 0;

	return flz(~word) + 1;
}
#define fls64(x)   generic_fls64(x)

/*
 * find_next_zero_bit - find the first zero 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
 */
static inline unsigned long find_next_zero_bit(const unsigned long *addr,
	unsigned long size, unsigned long offset)
{
	const unsigned long *p = addr + (offset >> SZLONG_LOG);
	unsigned long result = offset & ~SZLONG_MASK;
	unsigned long tmp;

	if (offset >= size)
		return size;
	size -= result;
	offset &= SZLONG_MASK;
	if (offset) {
		tmp = *(p++);
		tmp |= ~0UL >> (_MIPS_SZLONG-offset);
		if (size < _MIPS_SZLONG)
			goto found_first;
		if (~tmp)
			goto found_middle;
		size -= _MIPS_SZLONG;
		result += _MIPS_SZLONG;
	}
	while (size & ~SZLONG_MASK) {
		if (~(tmp = *(p++)))
			goto found_middle;
		result += _MIPS_SZLONG;
		size -= _MIPS_SZLONG;
	}
	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);
}

#define find_first_zero_bit(addr, size) \
	find_next_zero_bit((addr), (size), 0)

/*
 * 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
 */
static inline unsigned long find_next_bit(const unsigned long *addr,
	unsigned long size, unsigned long offset)
{
	const unsigned long *p = addr + (offset >> SZLONG_LOG);
	unsigned long result = offset & ~SZLONG_MASK;
	unsigned long tmp;

	if (offset >= size)
		return size;
	size -= result;
	offset &= SZLONG_MASK;
	if (offset) {
		tmp = *(p++);
		tmp &= ~0UL << offset;
		if (size < _MIPS_SZLONG)
			goto found_first;
		if (tmp)
			goto found_middle;
		size -= _MIPS_SZLONG;
		result += _MIPS_SZLONG;
	}
	while (size & ~SZLONG_MASK) {
		if ((tmp = *(p++)))
			goto found_middle;
		result += _MIPS_SZLONG;
		size -= _MIPS_SZLONG;
	}
	if (!size)
		return result;
	tmp = *p;

found_first:
	tmp &= ~0UL >> (_MIPS_SZLONG - size);
	if (tmp == 0UL)			/* Are any bits set? */
		return result + size;	/* Nope. */
found_middle:
	return result + __ffs(tmp);
}

/*
 * find_first_bit - find the first set bit in a memory region
 * @addr: The address to start the search at
 * @size: The maximum size to search
 *
 * Returns the bit-number of the first set bit, not the number of the byte
 * containing a bit.
 */
#define find_first_bit(addr, size) \
	find_next_bit((addr), (size), 0)

#ifdef __KERNEL__

/*
 * Every architecture must define this function. It's the fastest
 * way of searching a 140-bit bitmap where the first 100 bits are
 * unlikely to be set. It's guaranteed that at least one of the 140
 * bits is cleared.
 */
static inline int sched_find_first_bit(const unsigned long *b)
{
#ifdef CONFIG_32BIT
	if (unlikely(b[0]))
		return __ffs(b[0]);
	if (unlikely(b[1]))
		return __ffs(b[1]) + 32;
	if (unlikely(b[2]))
		return __ffs(b[2]) + 64;
	if (b[3])
		return __ffs(b[3]) + 96;
	return __ffs(b[4]) + 128;
#endif
#ifdef CONFIG_64BIT
	if (unlikely(b[0]))
		return __ffs(b[0]);
	if (unlikely(b[1]))
		return __ffs(b[1]) + 64;
	return __ffs(b[2]) + 128;
#endif
}

/*
 * hweightN - returns the hamming weight of a N-bit word
 * @x: the word to weigh
 *
 * The Hamming Weight of a number is the total number of bits set in it.
 */

#define hweight64(x)	generic_hweight64(x)
#define hweight32(x)	generic_hweight32(x)
#define hweight16(x)	generic_hweight16(x)
#define hweight8(x)	generic_hweight8(x)

static inline int __test_and_set_le_bit(unsigned long nr, unsigned long *addr)
{
	unsigned char	*ADDR = (unsigned char *) addr;
	int		mask, retval;

	ADDR += nr >> 3;
	mask = 1 << (nr & 0x07);
	retval = (mask & *ADDR) != 0;
	*ADDR |= mask;

	return retval;
}

static inline int __test_and_clear_le_bit(unsigned long nr, unsigned long *addr)
{
	unsigned char	*ADDR = (unsigned char *) addr;
	int		mask, retval;

	ADDR += nr >> 3;
	mask = 1 << (nr & 0x07);
	retval = (mask & *ADDR) != 0;
	*ADDR &= ~mask;

	return retval;
}

static inline int test_le_bit(unsigned long nr, const unsigned long * addr)
{
	const unsigned char	*ADDR = (const unsigned char *) addr;
	int			mask;

	ADDR += nr >> 3;
	mask = 1 << (nr & 0x07);

	return ((mask & *ADDR) != 0);
}

static inline unsigned long find_next_zero_le_bit(unsigned long *addr,
	unsigned long size, unsigned long offset)
{
	unsigned long *p = ((unsigned long *) addr) + (offset >> SZLONG_LOG);
	unsigned long result = offset & ~SZLONG_MASK;
	unsigned long tmp;

	if (offset >= size)
		return size;
	size -= result;
	offset &= SZLONG_MASK;
	if (offset) {
		tmp = cpu_to_lelongp(p++);
		tmp |= ~0UL >> (_MIPS_SZLONG-offset); /* bug or feature ? */
		if (size < _MIPS_SZLONG)
			goto found_first;
		if (~tmp)
			goto found_middle;
		size -= _MIPS_SZLONG;
		result += _MIPS_SZLONG;
	}
	while (size & ~SZLONG_MASK) {
		if (~(tmp = cpu_to_lelongp(p++)))
			goto found_middle;
		result += _MIPS_SZLONG;
		size -= _MIPS_SZLONG;
	}
	if (!size)
		return result;
	tmp = cpu_to_lelongp(p);

found_first:
	tmp |= ~0UL << size;
	if (tmp == ~0UL)		/* Are any bits zero? */
		return result + size;	/* Nope. */

found_middle:
	return result + ffz(tmp);
}

#define find_first_zero_le_bit(addr, size) \
	find_next_zero_le_bit((addr), (size), 0)

#define ext2_set_bit(nr,addr) \
	__test_and_set_le_bit((nr),(unsigned long*)addr)
#define ext2_clear_bit(nr, addr) \
	__test_and_clear_le_bit((nr),(unsigned long*)addr)
 #define ext2_set_bit_atomic(lock, nr, addr)		\
({							\
	int ret;					\
	spin_lock(lock);				\
	ret = ext2_set_bit((nr), (addr));		\
	spin_unlock(lock);				\
	ret;						\
})

#define ext2_clear_bit_atomic(lock, nr, addr)		\
({							\
	int ret;					\
	spin_lock(lock);				\
	ret = ext2_clear_bit((nr), (addr));		\
	spin_unlock(lock);				\
	ret;						\
})
#define ext2_test_bit(nr, addr)	test_le_bit((nr),(unsigned long*)addr)
#define ext2_find_first_zero_bit(addr, size) \
	find_first_zero_le_bit((unsigned long*)addr, size)
#define ext2_find_next_zero_bit(addr, size, off) \
	find_next_zero_le_bit((unsigned long*)addr, size, off)

/*
 * Bitmap functions for the minix filesystem.
 *
 * FIXME: These assume that Minix uses the native byte/bitorder.
 * This limits the Minix filesystem's value for data exchange very much.
 */
#define minix_test_and_set_bit(nr,addr) test_and_set_bit(nr,addr)
#define minix_set_bit(nr,addr) set_bit(nr,addr)
#define minix_test_and_clear_bit(nr,addr) test_and_clear_bit(nr,addr)
#define minix_test_bit(nr,addr) test_bit(nr,addr)
#define minix_find_first_zero_bit(addr,size) find_first_zero_bit(addr,size)

#endif /* __KERNEL__ */

#endif /* _ASM_BITOPS_H */