| #ifndef _BITS_STRINGS_H |
| #define _BITS_STRINGS_H |
| |
| /** @file |
| * |
| * String functions |
| * |
| */ |
| |
| FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); |
| |
| /** |
| * Find first (i.e. least significant) set bit |
| * |
| * @v value Value |
| * @ret lsb Least significant bit set in value (LSB=1), or zero |
| */ |
| static inline __attribute__ (( always_inline )) int __ffsll ( long long value ){ |
| unsigned long long bits = value; |
| unsigned long long lsb; |
| unsigned int lz; |
| |
| /* Extract least significant set bit */ |
| lsb = ( bits & -bits ); |
| |
| /* Count number of leading zeroes before LSB */ |
| __asm__ ( "clz %0, %1" : "=r" ( lz ) : "r" ( lsb ) ); |
| |
| return ( 64 - lz ); |
| } |
| |
| /** |
| * Find first (i.e. least significant) set bit |
| * |
| * @v value Value |
| * @ret lsb Least significant bit set in value (LSB=1), or zero |
| */ |
| static inline __attribute__ (( always_inline )) int __ffsl ( long value ) { |
| |
| return __ffsll ( value ); |
| } |
| |
| /** |
| * Find last (i.e. most significant) set bit |
| * |
| * @v value Value |
| * @ret msb Most significant bit set in value (LSB=1), or zero |
| */ |
| static inline __attribute__ (( always_inline )) int __flsll ( long long value ){ |
| unsigned int lz; |
| |
| /* Count number of leading zeroes */ |
| __asm__ ( "clz %0, %1" : "=r" ( lz ) : "r" ( value ) ); |
| |
| return ( 64 - lz ); |
| } |
| |
| /** |
| * Find last (i.e. most significant) set bit |
| * |
| * @v value Value |
| * @ret msb Most significant bit set in value (LSB=1), or zero |
| */ |
| static inline __attribute__ (( always_inline )) int __flsl ( long value ) { |
| |
| return __flsll ( value ); |
| } |
| |
| #endif /* _BITS_STRINGS_H */ |
