src/base/bitfield.hh

67  * from 'val' and right justify it.  MSB is numbered 63, LSB is 0.
72 bits(T val, int first, int last)
75     return (val >> last) & mask(nbits);
79  * Extract the bit from this position from 'val' and right justify it.
84 bits(T val, int bit)
86     return bits(val, bit, bit);
96 mbits(T val, int first, int last)
98     return val & (mask(first+1) & ~mask(last));
113 sext(uint64_t val)
115     int sign_bit = bits(val, N-1, N-1);
116     return sign_bit ? (val | ~mask(N)) : val;
120  * Return val with bits first to last set to bit_val
125 insertBits(T val, int first, int last, B bit_val)
129     return ((t_bit_val << last) & bmask) | (val & ~bmask);
138 insertBits(T val, int bit, B bit_val)
140     return insertBits(val, bit, bit, bit_val);
144  * A convenience function to replace bits first to last of val with bit_val
150 replaceBits(T& val, int first, int last, B bit_val)
152     val = insertBits(val, first, last, bit_val);
159 replaceBits(T& val, int bit, B bit_val)
161     val = insertBits(val, bit, bit, bit_val);
172  * @param val: variable lenght word
178 reverseBits(T val, std::size_t size = sizeof(T))
185     for (auto byte = 0; byte < size; byte++, val = static_cast<T>(val >> 8)) {
186         output = (output << 8) | reverseLookUpTable[val & 0xFF];
197 findMsbSet(uint64_t val) {
199     if (!val)
201     if (bits(val, 63,32)) { msb += 32; val >>= 32; }
202     if (bits(val, 31,16)) { msb += 16; val >>= 16; }
203     if (bits(val, 15,8))  { msb += 8;  val >>= 8;  }
204     if (bits(val, 7,4))   { msb += 4;  val >>= 4;  }
205     if (bits(val, 3,2))   { msb += 2;  val >>= 2;  }
206     if (bits(val, 1,1))   { msb += 1; }
214 findLsbSet(uint64_t val) {
216     if (!val)
217         return sizeof(val) * 8;
218     if (!bits(val, 31,0)) { lsb += 32; val >>= 32; }
219     if (!bits(val, 15,0)) { lsb += 16; val >>= 16; }
220     if (!bits(val, 7,0))  { lsb += 8;  val >>= 8;  }
221     if (!bits(val, 3,0))  { lsb += 4;  val >>= 4;  }
222     if (!bits(val, 1,0))  { lsb += 2;  val >>= 2;  }
223     if (!bits(val, 0,0))  { lsb += 1; }
242 popCount(uint64_t val) {
247     return __builtin_popcountl(val);
254     val -= (val >> 1) & m1;               // 2 bits count -> 2 bits
255     val = (val & m2) + ((val >> 2) & m2); // 4 bits count -> 4 bits
256     val = (val + (val >> 4)) & m4;        // 8 bits count -> 8 bits
257     return (val * sum) >> 56;             // horizontal sum
271 inline uint64_t alignToPowerOfTwo(uint64_t val)
273     val--;
274     val |= val >> 1;
275     val |= val >> 2;
276     val |= val >> 4;
277     val |= val >> 8;
278     val |= val >> 16;
279     val |= val >> 32;
280     val++;
282     return val;