Line data    Source code

       1             : /* SPDX-License-Identifier: GPL-2.0 */
       2             : #ifndef _ASM_GENERIC_BITOPS_FLS64_H_
       3             : #define _ASM_GENERIC_BITOPS_FLS64_H_
       4             : 
       5             : #include <asm/types.h>
       6             : 
       7             : /**
       8             :  * fls64 - find last set bit in a 64-bit word
       9             :  * @x: the word to search
      10             :  *
      11             :  * This is defined in a similar way as the libc and compiler builtin
      12             :  * ffsll, but returns the position of the most significant set bit.
      13             :  *
      14             :  * fls64(value) returns 0 if value is 0 or the position of the last
      15             :  * set bit if value is nonzero. The last (most significant) bit is
      16             :  * at position 64.
      17             :  */
      18             : #if BITS_PER_LONG == 32
      19             : static __always_inline int fls64(__u64 x)
      20             : {
      21             :         __u32 h = x >> 32;
      22             :         if (h)
      23             :                 return fls(h) + 32;
      24             :         return fls(x);
      25             : }
      26             : #elif BITS_PER_LONG == 64
      27             : static __always_inline int fls64(__u64 x)
      28             : {
      29 45306433798 :         if (x == 0)
      30             :                 return 0;
      31 45105459073 :         return __fls(x) + 1;
      32             : }
      33             : #else
      34             : #error BITS_PER_LONG not 32 or 64
      35             : #endif
      36             : 
      37             : #endif /* _ASM_GENERIC_BITOPS_FLS64_H_ */