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Code Issues Releases Wiki Activity

Implement PEXT based attacks

Browse source 
According to:

https://chessprogramming.wikispaces.com/BMI2#PEXTBitboards

No functional change.
This commit is contained in:
Marco Costalba 2014-04-07 16:27:14 +02:00
parent 2bfe61c33b
commit c556fe1d71
3 changed files with 18 additions and 1 deletions
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10
src/bitboard.cpp
View file

@ -296,7 +296,12 @@ namespace {
b = size = 0;
do {
occupancy[size] = b;
reference[size++] = sliding_attack(deltas, s, b);
reference[size] = sliding_attack(deltas, s, b);
if (HasPext)
attacks[s][pext(occupancy[size], masks[s])] = reference[size];
size++;
b = (b - masks[s]) & masks[s];
} while (b);
@ -305,6 +310,9 @@ namespace {
if (s < SQ_H8)
attacks[s + 1] = attacks[s] + size;
if (HasPext)
continue;
booster = MagicBoosters[Is64Bit][rank_of(s)];
// Find a magic for square 's' picking up an (almost) random number

3
src/bitboard.h
View file

@ -243,6 +243,9 @@ FORCE_INLINE unsigned magic_index(Square s, Bitboard occ) {
Bitboard* const Magics = Pt == ROOK ? RMagics : BMagics;
unsigned* const Shifts = Pt == ROOK ? RShifts : BShifts;
if (HasPext)
return unsigned(pext(occ, Masks[s]));
if (Is64Bit)
return unsigned(((occ & Masks[s]) * Magics[s]) >> Shifts[s]);

6
src/types.h
View file

@ -79,6 +79,12 @@ const bool HasPopCnt = true;
const bool HasPopCnt = false;
#endif
#ifdef USE_PEXT
const bool HasPext = true;
#else
const bool HasPext = false;
#endif
#ifdef IS_64BIT
const bool Is64Bit = true;
#else