include/asm-cris/arch-v10/bitops.h

   1 /* asm/arch/bitops.h for Linux/CRISv10 */
   2
   3 #ifndef _CRIS_ARCH_BITOPS_H
   4 #define _CRIS_ARCH_BITOPS_H
   5
   6 /*
   7  * Helper functions for the core of the ff[sz] functions, wrapping the
   8  * syntactically awkward asms.  The asms compute the number of leading
   9  * zeroes of a bits-in-byte and byte-in-word and word-in-dword-swapped
  10  * number.  They differ in that the first function also inverts all bits
  11  * in the input.
  12  */
  13 static inline unsigned long cris_swapnwbrlz(unsigned long w)
  14 {
  15         /* Let's just say we return the result in the same register as the
  16            input.  Saying we clobber the input but can return the result
  17            in another register:
  18            !  __asm__ ("swapnwbr %2\n\tlz %2,%0"
  19            !          : "=r,r" (res), "=r,X" (dummy) : "1,0" (w));
  20            confuses gcc (sched.c, gcc from cris-dist-1.14).  */
  21
  22         unsigned long res;
  23         __asm__ ("swapnwbr %0 \n\t"
  24                  "lz %0,%0"
  25                  : "=r" (res) : "0" (w));
  26         return res;
  27 }
  28
  29 static inline unsigned long cris_swapwbrlz(unsigned long w)
  30 {
  31         unsigned res;
  32         __asm__ ("swapwbr %0 \n\t"
  33                  "lz %0,%0"
  34                  : "=r" (res)
  35                  : "0" (w));
  36         return res;
  37 }
  38
  39 /*
  40  * ffz = Find First Zero in word. Undefined if no zero exists,
  41  * so code should check against ~0UL first..
  42  */
  43 static inline unsigned long ffz(unsigned long w)
  44 {
  45         return cris_swapnwbrlz(w);
  46 }
  47
  48 /**
  49  * __ffs - find first bit in word.
  50  * @word: The word to search
  51  *
  52  * Undefined if no bit exists, so code should check against 0 first.
  53  */
  54 static inline unsigned long __ffs(unsigned long word)
  55 {
  56         return cris_swapnwbrlz(~word);
  57 }
  58
  59 /**
  60  * ffs - find first bit set
  61  * @x: the word to search
  62  *
  63  * This is defined the same way as
  64  * the libc and compiler builtin ffs routines, therefore
  65  * differs in spirit from the above ffz (man ffs).
  66  */
  67
  68 static inline unsigned long kernel_ffs(unsigned long w)
  69 {
  70         return w ? cris_swapwbrlz (w) + 1 : 0;
  71 }
  72
  73 #endif