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/* asm/bitops.h for Linux/CRIS
*
* TODO: asm versions if speed is needed
* set_bit, clear_bit and change_bit wastes cycles being only
* macros into test_and_set_bit etc.
* kernel-doc things (**) for macros are disabled
*
* All bit operations return 0 if the bit was cleared before the
* operation and != 0 if it was not.
*
* bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
*/
#ifndef _CRIS_BITOPS_H
#define _CRIS_BITOPS_H
/* Currently this is unsuitable for consumption outside the kernel. */
#ifdef __KERNEL__
#include <asm/system.h>
/* We use generic_ffs so get it; include guards resolve the possible
mutually inclusion. */
#include <linux/bitops.h>
/*
* Some hacks to defeat gcc over-optimizations..
*/
struct __dummy { unsigned long a[100]; };
#define ADDR (*(struct __dummy *) addr)
#define CONST_ADDR (*(const struct __dummy *) addr)
/*
* 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.
*/
#define set_bit(nr, addr) (void)test_and_set_bit(nr, addr)
/*
* 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.
*/
#define clear_bit(nr, addr) (void)test_and_clear_bit(nr, addr)
/*
* change_bit - Toggle a bit in memory
* @nr: Bit to clear
* @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.
*/
#define change_bit(nr, addr) (void)test_and_change_bit(nr, addr)
/*
* __change_bit - Toggle a bit in memory
* @nr: the bit to set
* @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.
*/
#define __change_bit(nr, addr) (void)__test_and_change_bit(nr, addr)
/**
* 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(int nr, void *addr)
{
unsigned int mask, retval;
unsigned long flags;
unsigned int *adr = (unsigned int *)addr;
adr += nr >> 5;
mask = 1 << (nr & 0x1f);
save_flags(flags);
cli();
retval = (mask & *adr) != 0;
*adr |= mask;
restore_flags(flags);
return retval;
}
/*
* clear_bit() doesn't provide any barrier for the compiler.
*/
#define smp_mb__before_clear_bit() barrier()
#define smp_mb__after_clear_bit() barrier()
/**
* test_and_clear_bit - Clear 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_clear_bit(int nr, void *addr)
{
unsigned int mask, retval;
unsigned long flags;
unsigned int *adr = (unsigned int *)addr;
adr += nr >> 5;
mask = 1 << (nr & 0x1f);
save_flags(flags);
cli();
retval = (mask & *adr) != 0;
*adr &= ~mask;
restore_flags(flags);
return retval;
}
/**
* __test_and_clear_bit - Clear 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_clear_bit(int nr, void *addr)
{
unsigned int mask, retval;
unsigned int *adr = (unsigned int *)addr;
adr += nr >> 5;
mask = 1 << (nr & 0x1f);
retval = (mask & *adr) != 0;
*adr &= ~mask;
return retval;
}
/**
* test_and_change_bit - Change a bit and return its new 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_change_bit(int nr, void *addr)
{
unsigned int mask, retval;
unsigned long flags;
unsigned int *adr = (unsigned int *)addr;
adr += nr >> 5;
mask = 1 << (nr & 0x1f);
save_flags(flags);
cli();
retval = (mask & *adr) != 0;
*adr ^= mask;
restore_flags(flags);
return retval;
}
/* WARNING: non atomic and it can be reordered! */
static __inline__ int __test_and_change_bit(int nr, void *addr)
{
unsigned int mask, retval;
unsigned int *adr = (unsigned int *)addr;
adr += nr >> 5;
mask = 1 << (nr & 0x1f);
retval = (mask & *adr) != 0;
*adr ^= mask;
return retval;
}
/**
* test_bit - Determine whether a bit is set
* @nr: bit number to test
* @addr: Address to start counting from
*
* This routine doesn't need to be atomic.
*/
static __inline__ int test_bit(int nr, const void *addr)
{
unsigned int mask;
unsigned int *adr = (unsigned int *)addr;
adr += nr >> 5;
mask = 1 << (nr & 0x1f);
return ((mask & *adr) != 0);
}
/*
* Find-bit routines..
*/
/*
* Helper functions for the core of the ff[sz] functions, wrapping the
* syntactically awkward asms. The asms compute the number of leading
* zeroes of a bits-in-byte and byte-in-word and word-in-dword-swapped
* number. They differ in that the first function also inverts all bits
* in the input.
*/
static __inline__ unsigned long cris_swapnwbrlz(unsigned long w)
{
/* Let's just say we return the result in the same register as the
input. Saying we clobber the input but can return the result
in another register:
! __asm__ ("swapnwbr %2\n\tlz %2,%0"
! : "=r,r" (res), "=r,X" (dummy) : "1,0" (w));
confuses gcc (sched.c, gcc from cris-dist-1.14). */
unsigned long res;
__asm__ ("swapnwbr %0 \n\t"
"lz %0,%0"
: "=r" (res) : "0" (w));
return res;
}
static __inline__ unsigned long cris_swapwbrlz(unsigned long w)
{
unsigned res;
__asm__ ("swapwbr %0 \n\t"
"lz %0,%0"
: "=r" (res)
: "0" (w));
return res;
}
/*
* ffz = Find First Zero in word. Undefined if no zero exists,
* so code should check against ~0UL first..
*/
static __inline__ unsigned long ffz(unsigned long w)
{
/* The generic_ffs function is used to avoid the asm when the
argument is a constant. */
return __builtin_constant_p (w)
? (~w ? (unsigned long) generic_ffs ((int) ~w) - 1 : 32)
: cris_swapnwbrlz (w);
}
/*
* Somewhat like ffz but the equivalent of generic_ffs: in contrast to
* ffz we return the first one-bit *plus one*.
*/
static __inline__ unsigned long ffs(unsigned long w)
{
/* The generic_ffs function is used to avoid the asm when the
argument is a constant. */
return __builtin_constant_p (w)
? (unsigned long) generic_ffs ((int) w)
: w ? cris_swapwbrlz (w) + 1 : 0;
}
/**
* 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__ int find_next_zero_bit (void * addr, int size, int offset)
{
unsigned long *p = ((unsigned long *) addr) + (offset >> 5);
unsigned long result = offset & ~31UL;
unsigned long tmp;
if (offset >= size)
return size;
size -= result;
offset &= 31UL;
if (offset) {
tmp = *(p++);
tmp |= ~0UL >> (32-offset);
if (size < 32)
goto found_first;
if (~tmp)
goto found_middle;
size -= 32;
result += 32;
}
while (size & ~31UL) {
if (~(tmp = *(p++)))
goto found_middle;
result += 32;
size -= 32;
}
if (!size)
return result;
tmp = *p;
found_first:
tmp |= ~0UL >> size;
found_middle:
return result + ffz(tmp);
}
/**
* find_first_zero_bit - find the first zero 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 zero bit, not the number of the byte
* containing a bit.
*/
#define find_first_zero_bit(addr, size) \
find_next_zero_bit((addr), (size), 0)
/*
* 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 hweight32(x) generic_hweight32(x)
#define hweight16(x) generic_hweight16(x)
#define hweight8(x) generic_hweight8(x)
#define ext2_set_bit test_and_set_bit
#define ext2_clear_bit test_and_clear_bit
#define ext2_test_bit test_bit
#define ext2_find_first_zero_bit find_first_zero_bit
#define ext2_find_next_zero_bit find_next_zero_bit
/* Bitmap functions for the minix filesystem. */
#define minix_set_bit(nr,addr) test_and_set_bit(nr,addr)
#define minix_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 /* _CRIS_BITOPS_H */
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