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#ifdef __KERNEL__
  19
  20#include <asm/proc-armv/system.h>
  21
  22#define smp_mb__before_clear_bit()      do { } while (0)
  23#define smp_mb__after_clear_bit()       do { } while (0)
  24
  25/*
  26 * Function prototypes to keep gcc -Wall happy.
  27 */
  28extern void set_bit(int nr, volatile void * addr);
  29
  30extern void clear_bit(int nr, volatile void * addr);
  31
  32extern void change_bit(int nr, volatile void * addr);
  33
  34static inline void __change_bit(int nr, volatile void *addr)
  35{
  36        unsigned long mask = BIT_MASK(nr);
  37        unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  38
  39        *p ^= mask;
  40}
  41
  42static inline int __test_and_set_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        unsigned long old = *p;
  47
  48        *p = old | mask;
  49        return (old & mask) != 0;
  50}
  51
  52static inline int test_and_set_bit(int nr, volatile void * addr)
  53{
  54        unsigned long flags;
  55        int out;
  56
  57        local_irq_save(flags);
  58        out = __test_and_set_bit(nr, addr);
  59        local_irq_restore(flags);
  60
  61        return out;
  62}
  63
  64static inline int __test_and_clear_bit(int nr, volatile void *addr)
  65{
  66        unsigned long mask = BIT_MASK(nr);
  67        unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  68        unsigned long old = *p;
  69
  70        *p = old & ~mask;
  71        return (old & mask) != 0;
  72}
  73
  74static inline int test_and_clear_bit(int nr, volatile void * addr)
  75{
  76        unsigned long flags;
  77        int out;
  78
  79        local_irq_save(flags);
  80        out = __test_and_clear_bit(nr, addr);
  81        local_irq_restore(flags);
  82
  83        return out;
  84}
  85
  86extern int test_and_change_bit(int nr, volatile void * addr);
  87
  88static inline int __test_and_change_bit(int nr, volatile void *addr)
  89{
  90        unsigned long mask = BIT_MASK(nr);
  91        unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  92        unsigned long old = *p;
  93
  94        *p = old ^ mask;
  95        return (old & mask) != 0;
  96}
  97
  98/*
  99 * This routine doesn't need to be atomic.
 100 */
 101static inline int test_bit(int nr, const void * addr)
 102{
 103    return ((unsigned char *) addr)[nr >> 3] & (1U << (nr & 7));
 104}
 105
 106static inline int __ilog2(unsigned int x)
 107{
 108        return generic_fls(x) - 1;
 109}
 110
 111/*
 112 * ffz = Find First Zero in word. Undefined if no zero exists,
 113 * so code should check against ~0UL first..
 114 */
 115static inline unsigned long ffz(unsigned long word)
 116{
 117        int k;
 118
 119        word = ~word;
 120        k = 31;
 121        if (word & 0x0000ffff) { k -= 16; word <<= 16; }
 122        if (word & 0x00ff0000) { k -= 8;  word <<= 8;  }
 123        if (word & 0x0f000000) { k -= 4;  word <<= 4;  }
 124        if (word & 0x30000000) { k -= 2;  word <<= 2;  }
 125        if (word & 0x40000000) { k -= 1; }
 126        return k;
 127}
 128
 129static inline int find_next_zero_bit(void *addr, int size, int offset)
 130{
 131        unsigned long *p = ((unsigned long *)addr) + (offset >> 5);
 132        unsigned long result = offset & ~31UL;
 133        unsigned long tmp;
 134
 135        if (offset >= size)
 136                return size;
 137        size -= result;
 138        offset &= 31UL;
 139        if (offset) {
 140                tmp = *(p++);
 141                tmp |= ~0UL >> (32-offset);
 142                if (size < 32)
 143                        goto found_first;
 144                if (~tmp)
 145                        goto found_middle;
 146                size -= 32;
 147                result += 32;
 148        }
 149        while (size & ~31UL) {
 150                tmp = *(p++);
 151                if (~tmp)
 152                        goto found_middle;
 153                result += 32;
 154                size -= 32;
 155        }
 156        if (!size)
 157                return result;
 158        tmp = *p;
 159
 160found_first:
 161        tmp |= ~0UL >> size;
 162found_middle:
 163        return result + ffz(tmp);
 164}
 165
 166/*
 167 * hweightN: returns the hamming weight (i.e. the number
 168 * of bits set) of a N-bit word
 169 */
 170
 171#define hweight32(x) generic_hweight32(x)
 172#define hweight16(x) generic_hweight16(x)
 173#define hweight8(x) generic_hweight8(x)
 174
 175#define find_first_zero_bit(addr, size) \
 176        find_next_zero_bit((addr), (size), 0)
 177
 178#define ext2_set_bit                    test_and_set_bit
 179#define ext2_clear_bit                  test_and_clear_bit
 180#define ext2_test_bit                   test_bit
 181#define ext2_find_first_zero_bit        find_first_zero_bit
 182#define ext2_find_next_zero_bit         find_next_zero_bit
 183
 184/* Bitmap functions for the minix filesystem. */
 185#define minix_test_and_set_bit(nr,addr) test_and_set_bit(nr,addr)
 186#define minix_set_bit(nr,addr)          set_bit(nr,addr)
 187#define minix_test_and_clear_bit(nr,addr)       test_and_clear_bit(nr,addr)
 188#define minix_test_bit(nr,addr)         test_bit(nr,addr)
 189#define minix_find_first_zero_bit(addr,size)    find_first_zero_bit(addr,size)
 190
 191#endif /* __KERNEL__ */
 192
 193#endif /* _ARM_BITOPS_H */
 194