LXR uboot/arch/arm/include/asm/bitops.h

   1/*
   2 * Copyright 1995, Russell King.
   3 * Various bits and pieces copyrights include:
   4 *  Linus Torvalds (test_bit).
   5 *
   6 * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
   7 *
   8 * Please note that the code in this file should never be included
   9 * from user space.  Many of these are not implemented in assembler
  10 * since they would be too costly.  Also, they require priviledged
  11 * instructions (which are not available from user mode) to ensure
  12 * that they are atomic.
  13 */
  14
  15#ifndef __ASM_ARM_BITOPS_H
  16#define __ASM_ARM_BITOPS_H
  17
  18#include <asm-generic/bitops/__ffs.h>
  19#include <asm-generic/bitops/__fls.h>
  20#include <asm-generic/bitops/fls.h>
  21#include <asm-generic/bitops/fls64.h>
  22
  23#ifdef __KERNEL__
  24
  25#ifndef __ASSEMBLY__
  26#include <linux/bitops.h>
  27#endif
  28#include <asm/proc-armv/system.h>
  29
  30#define smp_mb__before_clear_bit()      do { } while (0)
  31#define smp_mb__after_clear_bit()       do { } while (0)
  32
  33/*
  34 * Function prototypes to keep gcc -Wall happy.
  35 */
  36extern void set_bit(int nr, volatile void * addr);
  37
  38extern void clear_bit(int nr, volatile void * addr);
  39
  40extern void change_bit(int nr, volatile void * addr);
  41
  42static inline void __change_bit(int nr, volatile void *addr)
  43{
  44        unsigned long mask = BIT_MASK(nr);
  45        unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  46
  47        *p ^= mask;
  48}
  49
  50static inline int __test_and_set_bit(int nr, volatile void *addr)
  51{
  52        unsigned long mask = BIT_MASK(nr);
  53        unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  54        unsigned long old = *p;
  55
  56        *p = old | mask;
  57        return (old & mask) != 0;
  58}
  59
  60static inline int test_and_set_bit(int nr, volatile void * addr)
  61{
  62        unsigned long flags = 0;
  63        int out;
  64
  65        local_irq_save(flags);
  66        out = __test_and_set_bit(nr, addr);
  67        local_irq_restore(flags);
  68
  69        return out;
  70}
  71
  72static inline int __test_and_clear_bit(int nr, volatile void *addr)
  73{
  74        unsigned long mask = BIT_MASK(nr);
  75        unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  76        unsigned long old = *p;
  77
  78        *p = old & ~mask;
  79        return (old & mask) != 0;
  80}
  81
  82static inline int test_and_clear_bit(int nr, volatile void * addr)
  83{
  84        unsigned long flags = 0;
  85        int out;
  86
  87        local_irq_save(flags);
  88        out = __test_and_clear_bit(nr, addr);
  89        local_irq_restore(flags);
  90
  91        return out;
  92}
  93
  94extern int test_and_change_bit(int nr, volatile void * addr);
  95
  96static inline int __test_and_change_bit(int nr, volatile void *addr)
  97{
  98        unsigned long mask = BIT_MASK(nr);
  99        unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
 100        unsigned long old = *p;
 101
 102        *p = old ^ mask;
 103        return (old & mask) != 0;
 104}
 105
 106/*
 107 * This routine doesn't need to be atomic.
 108 */
 109static inline int test_bit(int nr, const void * addr)
 110{
 111    return ((unsigned char *) addr)[nr >> 3] & (1U << (nr & 7));
 112}
 113
 114static inline int __ilog2(unsigned int x)
 115{
 116        return generic_fls(x) - 1;
 117}
 118
 119#define ffz(x)  __ffs(~(x))
 120
 121static inline int find_next_zero_bit(void *addr, int size, int offset)
 122{
 123        unsigned long *p = ((unsigned long *)addr) + (offset / BITS_PER_LONG);
 124        unsigned long result = offset & ~(BITS_PER_LONG - 1);
 125        unsigned long tmp;
 126
 127        if (offset >= size)
 128                return size;
 129        size -= result;
 130        offset &= (BITS_PER_LONG - 1);
 131        if (offset) {
 132                tmp = *(p++);
 133                tmp |= ~0UL >> (BITS_PER_LONG - offset);
 134                if (size < BITS_PER_LONG)
 135                        goto found_first;
 136                if (~tmp)
 137                        goto found_middle;
 138                size -= BITS_PER_LONG;
 139                result += BITS_PER_LONG;
 140        }
 141        while (size & ~(BITS_PER_LONG - 1)) {
 142                tmp = *(p++);
 143                if (~tmp)
 144                        goto found_middle;
 145                result += BITS_PER_LONG;
 146                size -= BITS_PER_LONG;
 147        }
 148        if (!size)
 149                return result;
 150        tmp = *p;
 151
 152found_first:
 153        tmp |= ~0UL << size;
 154found_middle:
 155        return result + ffz(tmp);
 156}
 157
 158/*
 159 * hweightN: returns the hamming weight (i.e. the number
 160 * of bits set) of a N-bit word
 161 */
 162
 163#define hweight32(x) generic_hweight32(x)
 164#define hweight16(x) generic_hweight16(x)
 165#define hweight8(x) generic_hweight8(x)
 166
 167#define find_first_zero_bit(addr, size) \
 168        find_next_zero_bit((addr), (size), 0)
 169
 170#define ext2_set_bit                    test_and_set_bit
 171#define ext2_clear_bit                  test_and_clear_bit
 172#define ext2_test_bit                   test_bit
 173#define ext2_find_first_zero_bit        find_first_zero_bit
 174#define ext2_find_next_zero_bit         find_next_zero_bit
 175
 176/* Bitmap functions for the minix filesystem. */
 177#define minix_test_and_set_bit(nr,addr) test_and_set_bit(nr,addr)
 178#define minix_set_bit(nr,addr)          set_bit(nr,addr)
 179#define minix_test_and_clear_bit(nr,addr)       test_and_clear_bit(nr,addr)
 180#define minix_test_bit(nr,addr)         test_bit(nr,addr)
 181#define minix_find_first_zero_bit(addr,size)    find_first_zero_bit(addr,size)
 182
 183#endif /* __KERNEL__ */
 184
 185#endif /* _ARM_BITOPS_H */
 186