LXR linux/arch/cris/include/asm/bitops.h

   1/* asm/bitops.h for Linux/CRIS
   2 *
   3 * TODO: asm versions if speed is needed
   4 *
   5 * All bit operations return 0 if the bit was cleared before the
   6 * operation and != 0 if it was not.
   7 *
   8 * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
   9 */
  10
  11#ifndef _CRIS_BITOPS_H
  12#define _CRIS_BITOPS_H
  13
  14/* Currently this is unsuitable for consumption outside the kernel.  */
  15#ifdef __KERNEL__ 
  16
  17#ifndef _LINUX_BITOPS_H
  18#error only <linux/bitops.h> can be included directly
  19#endif
  20
  21#include <arch/bitops.h>
  22#include <asm/system.h>
  23#include <asm/atomic.h>
  24#include <linux/compiler.h>
  25
  26/*
  27 * set_bit - Atomically set a bit in memory
  28 * @nr: the bit to set
  29 * @addr: the address to start counting from
  30 *
  31 * This function is atomic and may not be reordered.  See __set_bit()
  32 * if you do not require the atomic guarantees.
  33 * Note that @nr may be almost arbitrarily large; this function is not
  34 * restricted to acting on a single-word quantity.
  35 */
  36
  37#define set_bit(nr, addr)    (void)test_and_set_bit(nr, addr)
  38
  39/*
  40 * clear_bit - Clears a bit in memory
  41 * @nr: Bit to clear
  42 * @addr: Address to start counting from
  43 *
  44 * clear_bit() is atomic and may not be reordered.  However, it does
  45 * not contain a memory barrier, so if it is used for locking purposes,
  46 * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit()
  47 * in order to ensure changes are visible on other processors.
  48 */
  49
  50#define clear_bit(nr, addr)  (void)test_and_clear_bit(nr, addr)
  51
  52/*
  53 * change_bit - Toggle a bit in memory
  54 * @nr: Bit to change
  55 * @addr: Address to start counting from
  56 *
  57 * change_bit() is atomic and may not be reordered.
  58 * Note that @nr may be almost arbitrarily large; this function is not
  59 * restricted to acting on a single-word quantity.
  60 */
  61
  62#define change_bit(nr, addr) (void)test_and_change_bit(nr, addr)
  63
  64/**
  65 * test_and_set_bit - Set a bit and return its old value
  66 * @nr: Bit to set
  67 * @addr: Address to count from
  68 *
  69 * This operation is atomic and cannot be reordered.  
  70 * It also implies a memory barrier.
  71 */
  72
  73static inline int test_and_set_bit(int nr, volatile unsigned long *addr)
  74{
  75        unsigned int mask, retval;
  76        unsigned long flags;
  77        unsigned int *adr = (unsigned int *)addr;
  78        
  79        adr += nr >> 5;
  80        mask = 1 << (nr & 0x1f);
  81        cris_atomic_save(addr, flags);
  82        retval = (mask & *adr) != 0;
  83        *adr |= mask;
  84        cris_atomic_restore(addr, flags);
  85        return retval;
  86}
  87
  88/*
  89 * clear_bit() doesn't provide any barrier for the compiler.
  90 */
  91#define smp_mb__before_clear_bit()      barrier()
  92#define smp_mb__after_clear_bit()       barrier()
  93
  94/**
  95 * test_and_clear_bit - Clear a bit and return its old value
  96 * @nr: Bit to clear
  97 * @addr: Address to count from
  98 *
  99 * This operation is atomic and cannot be reordered.  
 100 * It also implies a memory barrier.
 101 */
 102
 103static inline int test_and_clear_bit(int nr, volatile unsigned long *addr)
 104{
 105        unsigned int mask, retval;
 106        unsigned long flags;
 107        unsigned int *adr = (unsigned int *)addr;
 108        
 109        adr += nr >> 5;
 110        mask = 1 << (nr & 0x1f);
 111        cris_atomic_save(addr, flags);
 112        retval = (mask & *adr) != 0;
 113        *adr &= ~mask;
 114        cris_atomic_restore(addr, flags);
 115        return retval;
 116}
 117
 118/**
 119 * test_and_change_bit - Change a bit and return its old value
 120 * @nr: Bit to change
 121 * @addr: Address to count from
 122 *
 123 * This operation is atomic and cannot be reordered.  
 124 * It also implies a memory barrier.
 125 */
 126
 127static inline int test_and_change_bit(int nr, volatile unsigned long *addr)
 128{
 129        unsigned int mask, retval;
 130        unsigned long flags;
 131        unsigned int *adr = (unsigned int *)addr;
 132        adr += nr >> 5;
 133        mask = 1 << (nr & 0x1f);
 134        cris_atomic_save(addr, flags);
 135        retval = (mask & *adr) != 0;
 136        *adr ^= mask;
 137        cris_atomic_restore(addr, flags);
 138        return retval;
 139}
 140
 141#include <asm-generic/bitops/non-atomic.h>
 142
 143/*
 144 * Since we define it "external", it collides with the built-in
 145 * definition, which doesn't have the same semantics.  We don't want to
 146 * use -fno-builtin, so just hide the name ffs.
 147 */
 148#define ffs kernel_ffs
 149
 150#include <asm-generic/bitops/fls.h>
 151#include <asm-generic/bitops/__fls.h>
 152#include <asm-generic/bitops/fls64.h>
 153#include <asm-generic/bitops/hweight.h>
 154#include <asm-generic/bitops/find.h>
 155#include <asm-generic/bitops/lock.h>
 156
 157#include <asm-generic/bitops/ext2-non-atomic.h>
 158
 159#define ext2_set_bit_atomic(l,n,a)   test_and_set_bit(n,a)
 160#define ext2_clear_bit_atomic(l,n,a) test_and_clear_bit(n,a)
 161
 162#include <asm-generic/bitops/minix.h>
 163#include <asm-generic/bitops/sched.h>
 164
 165#endif /* __KERNEL__ */
 166
 167#endif /* _CRIS_BITOPS_H */
 168