Simpler PRNG and faster magics search

[stockfish] / src / bitboard.cpp

diff --git a/src/bitboard.cpp b/src/bitboard.cpp
index 5a4c8b6b82fd6fe5b3330fbbd1d3160ad9352672..dbaeb701cff9e6e29fc732895a71fda4408bc99e 100644 (file)
--- a/src/bitboard.cpp
+++ b/src/bitboard.cpp
@@ -22,17 +22,17 @@
 
 #include "bitboard.h"
 #include "bitcount.h"
-#include "rkiss.h"
+#include "misc.h"
 
-Bitboard RMasks[SQUARE_NB];
-Bitboard RMagics[SQUARE_NB];
-Bitboard* RAttacks[SQUARE_NB];
-unsigned RShifts[SQUARE_NB];
+Bitboard RookMasks[SQUARE_NB];
+Bitboard RookMagics[SQUARE_NB];
+Bitboard* RookAttacks[SQUARE_NB];
+unsigned RookShifts[SQUARE_NB];
 
-Bitboard BMasks[SQUARE_NB];
-Bitboard BMagics[SQUARE_NB];
-Bitboard* BAttacks[SQUARE_NB];
-unsigned BShifts[SQUARE_NB];
+Bitboard BishopMasks[SQUARE_NB];
+Bitboard BishopMagics[SQUARE_NB];
+Bitboard* BishopAttacks[SQUARE_NB];
+unsigned BishopShifts[SQUARE_NB];
 
 Bitboard SquareBB[SQUARE_NB];
 Bitboard FileBB[FILE_NB];
@@ -58,8 +58,8 @@ namespace {
 
   int MS1BTable[256];
   Square BSFTable[SQUARE_NB];
-  Bitboard RTable[0x19000]; // Storage space for rook attacks
-  Bitboard BTable[0x1480];  // Storage space for bishop attacks
+  Bitboard RookTable[0x19000];  // Storage space for rook attacks
+  Bitboard BishopTable[0x1480]; // Storage space for bishop attacks
 
   typedef unsigned (Fn)(Square, Bitboard);
 
@@ -195,11 +195,11 @@ void Bitboards::init() {
                       StepAttacksBB[make_piece(c, pt)][s] |= to;
               }
 
-  Square RDeltas[] = { DELTA_N,  DELTA_E,  DELTA_S,  DELTA_W  };
-  Square BDeltas[] = { DELTA_NE, DELTA_SE, DELTA_SW, DELTA_NW };
+  Square RookDeltas[] = { DELTA_N,  DELTA_E,  DELTA_S,  DELTA_W  };
+  Square BishopDeltas[] = { DELTA_NE, DELTA_SE, DELTA_SW, DELTA_NW };
 
-  init_magics(RTable, RAttacks, RMagics, RMasks, RShifts, RDeltas, magic_index<ROOK>);
-  init_magics(BTable, BAttacks, BMagics, BMasks, BShifts, BDeltas, magic_index<BISHOP>);
+  init_magics(RookTable, RookAttacks, RookMagics, RookMasks, RookShifts, RookDeltas, magic_index<ROOK>);
+  init_magics(BishopTable, BishopAttacks, BishopMagics, BishopMasks, BishopShifts, BishopDeltas, magic_index<BISHOP>);
 
   for (Square s1 = SQ_A1; s1 <= SQ_H8; ++s1)
   {
@@ -250,11 +250,10 @@ namespace {
   void init_magics(Bitboard table[], Bitboard* attacks[], Bitboard magics[],
                    Bitboard masks[], unsigned shifts[], Square deltas[], Fn index) {
 
-    int MagicBoosters[][RANK_NB] = { {  969, 1976, 2850,  542, 2069, 2852, 1708,  164 },
-                                     { 3101,  552, 3555,  926,  834,   26, 2131, 1117 } };
-    RKISS rk;
+    int seeds[][RANK_NB] = { { 8977, 44560, 54343, 38998,  5731, 95205, 104912, 17020 },
+                             {  728, 10316, 55013, 32803, 12281, 15100,  16645,   255 } };
     Bitboard occupancy[4096], reference[4096], edges, b;
-    int i, size, booster;
+    int i, size;
 
     // attacks[s] is a pointer to the beginning of the attacks table for square 's'
     attacks[SQ_A1] = table;
@@ -294,13 +293,13 @@ namespace {
         if (HasPext)
             continue;
 
-        booster = MagicBoosters[Is64Bit][rank_of(s)];
+        PRNG rng(seeds[Is64Bit][rank_of(s)]);
 
         // Find a magic for square 's' picking up an (almost) random number
         // until we find the one that passes the verification test.
         do {
             do
-                magics[s] = rk.magic_rand<Bitboard>(booster);
+                magics[s] = rng.sparse_rand<Bitboard>();
             while (popcount<Max15>((magics[s] * masks[s]) >> 56) < 6);
 
             std::memset(attacks[s], 0, size * sizeof(Bitboard));