bitops.h

来自「Linux Kernel 2.6.9 for OMAP1710」· C头文件 代码 · 共 521 行

#ifndef _PARISC_BITOPS_H
#define _PARISC_BITOPS_H

#include <linux/compiler.h>
#include <asm/system.h>
#include <asm/byteorder.h>
#include <asm/atomic.h>

/*
 * HP-PARISC specific bit operations
 * for a detailed description of the functions please refer
 * to include/asm-i386/bitops.h or kerneldoc
 */

#ifdef __LP64__
#   define SHIFT_PER_LONG 6
#ifndef BITS_PER_LONG
#   define BITS_PER_LONG 64
#endif
#else
#   define SHIFT_PER_LONG 5
#ifndef BITS_PER_LONG
#   define BITS_PER_LONG 32
#endif
#endif

#define CHOP_SHIFTCOUNT(x) ((x) & (BITS_PER_LONG - 1))


#define smp_mb__before_clear_bit()      smp_mb()
#define smp_mb__after_clear_bit()       smp_mb()

static __inline__ void set_bit(int nr, volatile unsigned long * address)
{
	unsigned long mask;
	unsigned long *addr = (unsigned long *) address;
	unsigned long flags;

	addr += (nr >> SHIFT_PER_LONG);
	mask = 1L << CHOP_SHIFTCOUNT(nr);
	atomic_spin_lock_irqsave(ATOMIC_HASH(addr), flags);
	*addr |= mask;
	atomic_spin_unlock_irqrestore(ATOMIC_HASH(addr), flags);
}

static __inline__ void __set_bit(int nr, volatile unsigned long * address)
{
	unsigned long mask;
	unsigned long *addr = (unsigned long *) address;

	addr += (nr >> SHIFT_PER_LONG);
	mask = 1L << CHOP_SHIFTCOUNT(nr);
	*addr |= mask;
}

static __inline__ void clear_bit(int nr, volatile unsigned long * address)
{
	unsigned long mask;
	unsigned long *addr = (unsigned long *) address;
	unsigned long flags;

	addr += (nr >> SHIFT_PER_LONG);
	mask = 1L << CHOP_SHIFTCOUNT(nr);
	atomic_spin_lock_irqsave(ATOMIC_HASH(addr), flags);
	*addr &= ~mask;
	atomic_spin_unlock_irqrestore(ATOMIC_HASH(addr), flags);
}

static __inline__ void __clear_bit(unsigned long nr, volatile unsigned long * address)
{
	unsigned long mask;
	unsigned long *addr = (unsigned long *) address;

	addr += (nr >> SHIFT_PER_LONG);
	mask = 1L << CHOP_SHIFTCOUNT(nr);
	*addr &= ~mask;
}

static __inline__ void change_bit(int nr, volatile unsigned long * address)
{
	unsigned long mask;
	unsigned long *addr = (unsigned long *) address;
	unsigned long flags;

	addr += (nr >> SHIFT_PER_LONG);
	mask = 1L << CHOP_SHIFTCOUNT(nr);
	atomic_spin_lock_irqsave(ATOMIC_HASH(addr), flags);
	*addr ^= mask;
	atomic_spin_unlock_irqrestore(ATOMIC_HASH(addr), flags);
}

static __inline__ void __change_bit(int nr, volatile unsigned long * address)
{
	unsigned long mask;
	unsigned long *addr = (unsigned long *) address;

	addr += (nr >> SHIFT_PER_LONG);
	mask = 1L << CHOP_SHIFTCOUNT(nr);
	*addr ^= mask;
}

static __inline__ int test_and_set_bit(int nr, volatile unsigned long * address)
{
	unsigned long mask;
	unsigned long *addr = (unsigned long *) address;
	int oldbit;
	unsigned long flags;

	addr += (nr >> SHIFT_PER_LONG);
	mask = 1L << CHOP_SHIFTCOUNT(nr);
	atomic_spin_lock_irqsave(ATOMIC_HASH(addr), flags);
	oldbit = (*addr & mask) ? 1 : 0;
	*addr |= mask;
	atomic_spin_unlock_irqrestore(ATOMIC_HASH(addr), flags);

	return oldbit;
}

static __inline__ int __test_and_set_bit(int nr, volatile unsigned long * address)
{
	unsigned long mask;
	unsigned long *addr = (unsigned long *) address;
	int oldbit;

	addr += (nr >> SHIFT_PER_LONG);
	mask = 1L << CHOP_SHIFTCOUNT(nr);
	oldbit = (*addr & mask) ? 1 : 0;
	*addr |= mask;

	return oldbit;
}

static __inline__ int test_and_clear_bit(int nr, volatile unsigned long * address)
{
	unsigned long mask;
	unsigned long *addr = (unsigned long *) address;
	int oldbit;
	unsigned long flags;

	addr += (nr >> SHIFT_PER_LONG);
	mask = 1L << CHOP_SHIFTCOUNT(nr);
	atomic_spin_lock_irqsave(ATOMIC_HASH(addr), flags);
	oldbit = (*addr & mask) ? 1 : 0;
	*addr &= ~mask;
	atomic_spin_unlock_irqrestore(ATOMIC_HASH(addr), flags);

	return oldbit;
}

static __inline__ int __test_and_clear_bit(int nr, volatile unsigned long * address)
{
	unsigned long mask;
	unsigned long *addr = (unsigned long *) address;
	int oldbit;

	addr += (nr >> SHIFT_PER_LONG);
	mask = 1L << CHOP_SHIFTCOUNT(nr);
	oldbit = (*addr & mask) ? 1 : 0;
	*addr &= ~mask;

	return oldbit;
}

static __inline__ int test_and_change_bit(int nr, volatile unsigned long * address)
{
	unsigned long mask;
	unsigned long *addr = (unsigned long *) address;
	int oldbit;
	unsigned long flags;

	addr += (nr >> SHIFT_PER_LONG);
	mask = 1L << CHOP_SHIFTCOUNT(nr);
	atomic_spin_lock_irqsave(ATOMIC_HASH(addr), flags);
	oldbit = (*addr & mask) ? 1 : 0;
	*addr ^= mask;
	atomic_spin_unlock_irqrestore(ATOMIC_HASH(addr), flags);

	return oldbit;
}

static __inline__ int __test_and_change_bit(int nr, volatile unsigned long * address)
{
	unsigned long mask;
	unsigned long *addr = (unsigned long *) address;
	int oldbit;

	addr += (nr >> SHIFT_PER_LONG);
	mask = 1L << CHOP_SHIFTCOUNT(nr);
	oldbit = (*addr & mask) ? 1 : 0;
	*addr ^= mask;

	return oldbit;
}

static __inline__ int test_bit(int nr, const volatile unsigned long *address)
{
	unsigned long mask;
	const unsigned long *addr = (const unsigned long *)address;
	
	addr += (nr >> SHIFT_PER_LONG);
	mask = 1L << CHOP_SHIFTCOUNT(nr);
	
	return !!(*addr & mask);
}

#ifdef __KERNEL__

/**
 * __ffs - find first bit in word. returns 0 to "BITS_PER_LONG-1".
 * @word: The word to search
 *
 * __ffs() return is undefined if no bit is set.
 *
 * 32-bit fast __ffs by LaMont Jones "lamont At hp com".
 * 64-bit enhancement by Grant Grundler "grundler At parisc-linux org".
 * (with help from willy/jejb to get the semantics right)
 *
 * This algorithm avoids branches by making use of nullification.
 * One side effect of "extr" instructions is it sets PSW[N] bit.
 * How PSW[N] (nullify next insn) gets set is determined by the 
 * "condition" field (eg "<>" or "TR" below) in the extr* insn.
 * Only the 1st and one of either the 2cd or 3rd insn will get executed.
 * Each set of 3 insn will get executed in 2 cycles on PA8x00 vs 16 or so
 * cycles for each mispredicted branch.
 */

static __inline__ unsigned long __ffs(unsigned long x)
{
	unsigned long ret;

	__asm__(
#if BITS_PER_LONG > 32
		" ldi       63,%1\n"
		" extrd,u,*<>  %0,63,32,%%r0\n"
		" extrd,u,*TR  %0,31,32,%0\n"	/* move top 32-bits down */
		" addi    -32,%1,%1\n"
#else
		" ldi       31,%1\n"
#endif
		" extru,<>  %0,31,16,%%r0\n"
		" extru,TR  %0,15,16,%0\n"	/* xxxx0000 -> 0000xxxx */
		" addi    -16,%1,%1\n"
		" extru,<>  %0,31,8,%%r0\n"
		" extru,TR  %0,23,8,%0\n"	/* 0000xx00 -> 000000xx */
		" addi    -8,%1,%1\n"
		" extru,<>  %0,31,4,%%r0\n"
		" extru,TR  %0,27,4,%0\n"	/* 000000x0 -> 0000000x */
		" addi    -4,%1,%1\n"
		" extru,<>  %0,31,2,%%r0\n"
		" extru,TR  %0,29,2,%0\n"	/* 0000000y, 1100b -> 0011b */
		" addi    -2,%1,%1\n"
		" extru,=  %0,31,1,%%r0\n"	/* check last bit */
		" addi    -1,%1,%1\n"
			: "+r" (x), "=r" (ret) );
	return ret;
}

/* Undefined if no bit is zero. */
#define ffz(x)	__ffs(~x)

/*
 * ffs: find first bit set. returns 1 to BITS_PER_LONG or 0 (if none set)
 * This is defined the same way as the libc and compiler builtin
 * ffs routines, therefore differs in spirit from the above ffz (man ffs).
 */
static __inline__ int ffs(int x)
{
	return x ? (__ffs((unsigned long)x) + 1) : 0;
}

/*
 * fls: find last (most significant) bit set.
 * fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
 */

static __inline__ int fls(int x)
{
	int ret;
	if (!x)
		return 0;

	__asm__(
	"	ldi		1,%1\n"
	"	extru,<>	%0,15,16,%%r0\n"
	"	zdep,TR		%0,15,16,%0\n"		/* xxxx0000 */
	"	addi		16,%1,%1\n"
	"	extru,<>	%0,7,8,%%r0\n"
	"	zdep,TR		%0,23,24,%0\n"		/* xx000000 */
	"	addi		8,%1,%1\n"
	"	extru,<>	%0,3,4,%%r0\n"
	"	zdep,TR		%0,27,28,%0\n"		/* x0000000 */
	"	addi		4,%1,%1\n"
	"	extru,<>	%0,1,2,%%r0\n"
	"	zdep,TR		%0,29,30,%0\n"		/* y0000000 (y&3 = 0) */
	"	addi		2,%1,%1\n"
	"	extru,=		%0,0,1,%%r0\n"
	"	addi		1,%1,%1\n"		/* if y & 8, add 1 */
		: "+r" (x), "=r" (ret) );

	return ret;
}

/*
 * hweightN: returns the hamming weight (i.e. the number
 * of bits set) of a N-bit word
 */
#define hweight64(x)						\
({								\
	unsigned long __x = (x);				\
	unsigned int __w;					\
	__w = generic_hweight32((unsigned int) __x);		\
	__w += generic_hweight32((unsigned int) (__x>>32));	\
	__w;							\
})
#define hweight32(x) generic_hweight32(x)
#define hweight16(x) generic_hweight16(x)
#define hweight8(x) generic_hweight8(x)

/*
 * 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)
{
#ifndef __LP64__
	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;
#else
	if (unlikely(b[0]))
		return __ffs(b[0]);
	if (unlikely(((unsigned int)b[1])))
		return __ffs(b[1]) + 64;
	if (b[1] >> 32)
		return __ffs(b[1] >> 32) + 96;
	return __ffs(b[2]) + 128;
#endif
}

#endif /* __KERNEL__ */

/*
 * This implementation of find_{first,next}_zero_bit was stolen from
 * Linus' asm-alpha/bitops.h.
 */
#define find_first_zero_bit(addr, size) \
	find_next_zero_bit((addr), (size), 0)

static __inline__ unsigned long find_next_zero_bit(const void * addr, unsigned long size, unsigned long offset)
{
	const unsigned long * p = ((unsigned long *) addr) + (offset >> SHIFT_PER_LONG);
	unsigned long result = offset & ~(BITS_PER_LONG-1);
	unsigned long tmp;

	if (offset >= size)
		return size;
	size -= result;
	offset &= (BITS_PER_LONG-1);
	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;
found_middle:
	return result + ffz(tmp);
}

static __inline__ unsigned long find_next_bit(const unsigned long *addr, unsigned long size, unsigned long offset)
{
	const unsigned long *p = addr + (offset >> 6);
	unsigned long result = offset & ~(BITS_PER_LONG-1);
	unsigned long tmp;

	if (offset >= size)
		return size;
	size -= result;
	offset &= (BITS_PER_LONG-1);
	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);
}

/**
 * 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)

#define _EXT2_HAVE_ASM_BITOPS_

#ifdef __KERNEL__
/*
 * test_and_{set,clear}_bit guarantee atomicity without
 * disabling interrupts.
 */
#ifdef __LP64__
#define ext2_set_bit(nr, addr)		test_and_set_bit((nr) ^ 0x38, (unsigned long *)addr)
#define ext2_set_bit_atomic(l,nr,addr)  test_and_set_bit((nr) ^ 0x38, (unsigned long *)addr)
#define ext2_clear_bit(nr, addr)	test_and_clear_bit((nr) ^ 0x38, (unsigned long *)addr)
#define ext2_clear_bit_atomic(l,nr,addr) test_and_clear_bit((nr) ^ 0x38, (unsigned long *)addr)
#else
#define ext2_set_bit(nr, addr)		test_and_set_bit((nr) ^ 0x18, (unsigned long *)addr)
#define ext2_set_bit_atomic(l,nr,addr)  test_and_set_bit((nr) ^ 0x18, (unsigned long *)addr)
#define ext2_clear_bit(nr, addr)	test_and_clear_bit((nr) ^ 0x18, (unsigned long *)addr)
#define ext2_clear_bit_atomic(l,nr,addr) test_and_clear_bit((nr) ^ 0x18, (unsigned long *)addr)
#endif

#endif	/* __KERNEL__ */

static __inline__ int ext2_test_bit(int nr, __const__ void * addr)
{
	__const__ unsigned char	*ADDR = (__const__ unsigned char *) addr;

	return (ADDR[nr >> 3] >> (nr & 7)) & 1;
}

/*
 * This implementation of ext2_find_{first,next}_zero_bit was stolen from
 * Linus' asm-alpha/bitops.h and modified for a big-endian machine.
 */

#define ext2_find_first_zero_bit(addr, size) \
        ext2_find_next_zero_bit((addr), (size), 0)

extern __inline__ unsigned long ext2_find_next_zero_bit(void *addr,
	unsigned long size, unsigned long offset)
{
	unsigned int *p = ((unsigned int *) addr) + (offset >> 5);
	unsigned int result = offset & ~31UL;
	unsigned int tmp;

	if (offset >= size)
		return size;
	size -= result;
	offset &= 31UL;
	if (offset) {
		tmp = cpu_to_le32p(p++);
		tmp |= ~0UL >> (32-offset);
		if (size < 32)
			goto found_first;
		if (tmp != ~0U)
			goto found_middle;
		size -= 32;
		result += 32;
	}
	while (size >= 32) {
		if ((tmp = cpu_to_le32p(p++)) != ~0U)
			goto found_middle;
		result += 32;
		size -= 32;
	}
	if (!size)
		return result;
	tmp = cpu_to_le32p(p);
found_first:
	tmp |= ~0U << size;
found_middle:
	return result + ffz(tmp);
}

/* Bitmap functions for the minix filesystem.  */
#define minix_test_and_set_bit(nr,addr) ext2_set_bit(nr,addr)
#define minix_set_bit(nr,addr) ((void)ext2_set_bit(nr,addr))
#define minix_test_and_clear_bit(nr,addr) ext2_clear_bit(nr,addr)
#define minix_test_bit(nr,addr) ext2_test_bit(nr,addr)
#define minix_find_first_zero_bit(addr,size) ext2_find_first_zero_bit(addr,size)

#endif /* _PARISC_BITOPS_H */