LXR linux/arch/cris/include/arch-v32/arch/bitops.h

   1#ifndef _ASM_CRIS_ARCH_BITOPS_H
   2#define _ASM_CRIS_ARCH_BITOPS_H
   3
   4/*
   5 * Helper functions for the core of the ff[sz] functions. They compute the
   6 * number of leading zeroes of a bits-in-byte, byte-in-word and
   7 * word-in-dword-swapped number. They differ in that the first function also
   8 * inverts all bits in the input.
   9 */
  10
  11static inline unsigned long
  12cris_swapnwbrlz(unsigned long w)
  13{
  14        unsigned long res;
  15
  16        __asm__ __volatile__ ("swapnwbr %0\n\t"
  17                              "lz %0,%0"
  18                              : "=r" (res) : "0" (w));
  19
  20        return res;
  21}
  22
  23static inline unsigned long
  24cris_swapwbrlz(unsigned long w)
  25{
  26        unsigned long res;
  27
  28        __asm__ __volatile__ ("swapwbr %0\n\t"
  29                              "lz %0,%0"
  30                              : "=r" (res) : "0" (w));
  31
  32        return res;
  33}
  34
  35/*
  36 * Find First Zero in word. Undefined if no zero exist, so the caller should
  37 * check against ~0 first.
  38 */
  39static inline unsigned long
  40ffz(unsigned long w)
  41{
  42        return cris_swapnwbrlz(w);
  43}
  44
  45/*
  46 * Find First Set bit in word. Undefined if no 1 exist, so the caller
  47 * should check against 0 first.
  48 */
  49static inline unsigned long
  50__ffs(unsigned long w)
  51{
  52        return cris_swapnwbrlz(~w);
  53}
  54
  55/*
  56 * Find First Bit that is set.
  57 */
  58static inline unsigned long
  59kernel_ffs(unsigned long w)
  60{
  61        return w ? cris_swapwbrlz (w) + 1 : 0;
  62}
  63
  64#endif /* _ASM_CRIS_ARCH_BITOPS_H */
  65