text: #ifndef XC_BITOPS_H
  #define XC_BITOPS_H 1
  
  /* bitmap operations for single threaded access */
  
  #include <stdlib.h>
  #include <string.h>
  
  #define BITS_PER_LONG (sizeof(unsigned long) * 8)
  #define ORDER_LONG (sizeof(unsigned long) == 4 ? 5 : 6)
  
  #define BITMAP_ENTRY(_nr,_bmap) ((_bmap))[(_nr)/BITS_PER_LONG]
  #define BITMAP_SHIFT(_nr) ((_nr) % BITS_PER_LONG)
  
  /* calculate required space for number of longs needed to hold nr_bits */
  static inline int bitmap_size(int nr_bits)
  {
      int nr_long, nr_bytes;
      nr_long = (nr_bits + BITS_PER_LONG - 1) >> ORDER_LONG;
      nr_bytes = nr_long * sizeof(unsigned long);
      return nr_bytes;
  }
  
  static inline unsigned long *bitmap_alloc(int nr_bits)
  {
      return calloc(1, bitmap_size(nr_bits));
  }
  
  static inline void bitmap_set(unsigned long *addr, int nr_bits)
  {
      memset(addr, 0xff, bitmap_size(nr_bits));
  }
  
  static inline void bitmap_clear(unsigned long *addr, int nr_bits)
  {
      memset(addr, 0, bitmap_size(nr_bits));
  }
  
  static inline int test_bit(int nr, unsigned long *addr)
  {
      return (BITMAP_ENTRY(nr, addr) >> BITMAP_SHIFT(nr)) & 1;
  }
  
  static inline void clear_bit(int nr, unsigned long *addr)
  {
      BITMAP_ENTRY(nr, addr) &= ~(1UL << BITMAP_SHIFT(nr));
  }
  
  static inline void set_bit(int nr, unsigned long *addr)
  {
      BITMAP_ENTRY(nr, addr) |= (1UL << BITMAP_SHIFT(nr));
  }
  
  static inline int test_and_clear_bit(int nr, unsigned long *addr)
  {
      int oldbit = test_bit(nr, addr);
      clear_bit(nr, addr);
      return oldbit;
  }
  
  static inline int test_and_set_bit(int nr, unsigned long *addr)
  {
      int oldbit = test_bit(nr, addr);
      set_bit(nr, addr);
      return oldbit;
  }
  
  static inline void bitmap_or(unsigned long *dst, const unsigned long *other,
                               int nr_bits)
  {
      int i, nr_longs = (bitmap_size(nr_bits) / sizeof(unsigned long));
      for ( i = 0; i < nr_longs; ++i )
          dst[i] |= other[i];
  }
  
  #endif  /* XC_BITOPS_H */
  