1 #ifndef FIO_FFZ_H 2 #define FIO_FFZ_H 3 4 static inline int __ffs(unsigned long word) 5 { 6 int r = 0; 7 8 #if BITS_PER_LONG == 64 9 if ((word & 0xffffffff) == 0) { 10 r += 32; 11 word >>= 32; 12 } 13 #endif 14 if (!(word & 0xffff)) { 15 word >>= 16; 16 r += 16; 17 } 18 if (!(word & 0xff)) { 19 word >>= 8; 20 r += 8; 21 } 22 if (!(word & 0xf)) { 23 word >>= 4; 24 r += 4; 25 } 26 if (!(word & 3)) { 27 word >>= 2; 28 r += 2; 29 } 30 if (!(word & 1)) { 31 word >>= 1; 32 r += 1; 33 } 34 35 return r; 36 } 37 38 static inline int ffz(unsigned long bitmask) 39 { 40 return __ffs(~bitmask); 41 } 42 43 #endif 44
