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
  20#ifdef __KERNEL__
  21
  22#include <asm/proc-armv/system.h>
  23
  24#define smp_mb__before_clear_bit()      do { } while (0)
  25#define smp_mb__after_clear_bit()       do { } while (0)
  26
  27/*
  28 * Function prototypes to keep gcc -Wall happy.
  29 */
  30extern void set_bit(int nr, volatile void * addr);
  31
  32extern void clear_bit(int nr, volatile void * addr);
  33
  34extern void change_bit(int nr, volatile void * addr);
  35
  36static inline void __change_bit(int nr, volatile void *addr)
  37{
  38        unsigned long mask = BIT_MASK(nr);
  39        unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  40
  41        *p ^= mask;
  42}
  43
  44static inline int __test_and_set_bit(int nr, volatile void *addr)
  45{
  46        unsigned long mask = BIT_MASK(nr);
  47        unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  48        unsigned long old = *p;
  49
  50        *p = old | mask;
  51        return (old & mask) != 0;
  52}
  53
  54static inline int test_and_set_bit(int nr, volatile void * addr)
  55{
  56        unsigned long flags = 0;
  57        int out;
  58
  59        local_irq_save(flags);
  60        out = __test_and_set_bit(nr, addr);
  61        local_irq_restore(flags);
  62
  63        return out;
  64}
  65
  66static inline int __test_and_clear_bit(int nr, volatile void *addr)
  67{
  68        unsigned long mask = BIT_MASK(nr);
  69        unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  70        unsigned long old = *p;
  71
  72        *p = old & ~mask;
  73        return (old & mask) != 0;
  74}
  75
  76static inline int test_and_clear_bit(int nr, volatile void * addr)
  77{
  78        unsigned long flags = 0;
  79        int out;
  80
  81        local_irq_save(flags);
  82        out = __test_and_clear_bit(nr, addr);
  83        local_irq_restore(flags);
  84
  85        return out;
  86}
  87
  88extern int test_and_change_bit(int nr, volatile void * addr);
  89
  90static inline int __test_and_change_bit(int nr, volatile void *addr)
  91{
  92        unsigned long mask = BIT_MASK(nr);
  93        unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  94        unsigned long old = *p;
  95
  96        *p = old ^ mask;
  97        return (old & mask) != 0;
  98}
  99
 100/*
 101 * This routine doesn't need to be atomic.
 102 */
 103static inline int test_bit(int nr, const void * addr)
 104{
 105    return ((unsigned char *) addr)[nr >> 3] & (1U << (nr & 7));
 106}
 107
 108static inline int __ilog2(unsigned int x)
 109{
 110        return generic_fls(x) - 1;
 111}
 112
 113#define ffz(x)  __ffs(~(x))
 114
 115static inline int find_next_zero_bit(void *addr, int size, int offset)
 116{
 117        unsigned long *p = ((unsigned long *)addr) + (offset / BITS_PER_LONG);
 118        unsigned long result = offset & ~(BITS_PER_LONG - 1);
 119        unsigned long tmp;
 120
 121        if (offset >= size)
 122                return size;
 123        size -= result;
 124        offset &= (BITS_PER_LONG - 1);
 125        if (offset) {
 126                tmp = *(p++);
 127                tmp |= ~0UL >> (BITS_PER_LONG - offset);
 128                if (size < BITS_PER_LONG)
 129                        goto found_first;
 130                if (~tmp)
 131                        goto found_middle;
 132                size -= BITS_PER_LONG;
 133                result += BITS_PER_LONG;
 134        }
 135        while (size & ~(BITS_PER_LONG - 1)) {
 136                tmp = *(p++);
 137                if (~tmp)
 138                        goto found_middle;
 139                result += BITS_PER_LONG;
 140                size -= BITS_PER_LONG;
 141        }
 142        if (!size)
 143                return result;
 144        tmp = *p;
 145
 146found_first:
 147        tmp |= ~0UL << size;
 148found_middle:
 149        return result + ffz(tmp);
 150}
 151
 152/*
 153 * hweightN: returns the hamming weight (i.e. the number
 154 * of bits set) of a N-bit word
 155 */
 156
 157#define hweight32(x) generic_hweight32(x)
 158#define hweight16(x) generic_hweight16(x)
 159#define hweight8(x) generic_hweight8(x)
 160
 161#define find_first_zero_bit(addr, size) \
 162        find_next_zero_bit((addr), (size), 0)
 163
 164#define ext2_set_bit                    test_and_set_bit
 165#define ext2_clear_bit                  test_and_clear_bit
 166#define ext2_test_bit                   test_bit
 167#define ext2_find_first_zero_bit        find_first_zero_bit
 168#define ext2_find_next_zero_bit         find_next_zero_bit
 169
 170/* Bitmap functions for the minix filesystem. */
 171#define minix_test_and_set_bit(nr,addr) test_and_set_bit(nr,addr)
 172#define minix_set_bit(nr,addr)          set_bit(nr,addr)
 173#define minix_test_and_clear_bit(nr,addr)       test_and_clear_bit(nr,addr)
 174#define minix_test_bit(nr,addr)         test_bit(nr,addr)
 175#define minix_find_first_zero_bit(addr,size)    find_first_zero_bit(addr,size)
 176
 177#endif /* __KERNEL__ */
 178
 179#include <asm-generic/bitops/__fls.h>
 180#include <asm-generic/bitops/fls.h>
 181#include <asm-generic/bitops/fls64.h>
 182
 183#endif /* _ARM_BITOPS_H */
 184