Small pick_magic() touches

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

diff --git a/src/bitboard.cpp b/src/bitboard.cpp
index 8c70a8e27b10820e27f288f28febfced33f91657..0e31d5d69adccca37458c0ca8b9ddf9b9d44d49f 100644 (file)
--- a/src/bitboard.cpp
+++ b/src/bitboard.cpp
@@ -65,8 +65,8 @@ namespace {
   Bitboard RAttacksTable[0x19000];
   Bitboard BAttacksTable[0x1480];
 
   Bitboard RAttacksTable[0x19000];
   Bitboard BAttacksTable[0x1480];
 

-  void do_magics(Bitboard magic[], Bitboard* attack[], Bitboard attTabl[],
-                 Bitboard mask[], int shift[], Square deltas[]);
+  void init_sliding_attacks(Bitboard magic[], Bitboard* attack[], Bitboard attTable[],
+                            Bitboard mask[], int shift[], Square delta[]);

 }
 
 
 }
 
 


@@ -226,8 +226,8 @@ void init_bitboards() {
   Square RDeltas[] = { DELTA_N,  DELTA_E,  DELTA_S,  DELTA_W  };
   Square BDeltas[] = { DELTA_NE, DELTA_SE, DELTA_SW, DELTA_NW };
 
   Square RDeltas[] = { DELTA_N,  DELTA_E,  DELTA_S,  DELTA_W  };
   Square BDeltas[] = { DELTA_NE, DELTA_SE, DELTA_SW, DELTA_NW };
 

-  do_magics(BMult, BAttacks, BAttacksTable, BMask, BShift, BDeltas);
-  do_magics(RMult, RAttacks, RAttacksTable, RMask, RShift, RDeltas);
+  init_sliding_attacks(BMult, BAttacks, BAttacksTable, BMask, BShift, BDeltas);
+  init_sliding_attacks(RMult, RAttacks, RAttacksTable, RMask, RShift, RDeltas);

 
   for (Square s = SQ_A1; s <= SQ_H8; s++)
   {
 
   for (Square s = SQ_A1; s <= SQ_H8; s++)
   {


@@ -293,10 +293,6 @@ namespace {
   Bitboard pick_magic(Bitboard mask, RKISS& rk, int booster) {
 
     Bitboard magic;
   Bitboard pick_magic(Bitboard mask, RKISS& rk, int booster) {
 
     Bitboard magic;

-    int lsb;
-
-    if (!Is64)
-        lsb = first_1(mask);

 
     // Advance PRNG state of a quantity known to be the optimal to
     // quickly retrieve all the magics.
 
     // Advance PRNG state of a quantity known to be the optimal to
     // quickly retrieve all the magics.


@@ -308,41 +304,40 @@ namespace {
         magic = rk.rand<Bitboard>() & rk.rand<Bitboard>();
         magic &= Is64 ? rk.rand<Bitboard>() : (rk.rand<Bitboard>() | rk.rand<Bitboard>());
 
         magic = rk.rand<Bitboard>() & rk.rand<Bitboard>();
         magic &= Is64 ? rk.rand<Bitboard>() : (rk.rand<Bitboard>() | rk.rand<Bitboard>());
 

-        if (   BitCount8Bit[(mask * magic) >> 56] >= 6
-            && (Is64 || BitCount8Bit[(lsb * magic) >> 56]))
+        if (BitCount8Bit[(mask * magic) >> 56] >= 6)

             return magic;
     }
   }
 
             return magic;
     }
   }
 

-  void do_magics(Bitboard magic[], Bitboard* attack[], Bitboard attTabl[],
-                 Bitboard mask[], int shift[], Square deltas[]) {
-
-    const int  MagicBoosters32[] = { 43, 53, 76, 17, 51, 65, 55, 23 };
-    const int  MagicBoosters64[] = { 26, 21, 21, 32, 31,  9,  5, 11 };
+  void init_sliding_attacks(Bitboard magic[], Bitboard* attack[], Bitboard attTable[],
+                            Bitboard mask[], int shift[], Square delta[]) {

 
 

+    const int  MagicBoosters[][8] = { { 55, 11, 17,  2, 39,  3, 31, 44 },
+                                      { 26, 21, 21, 32, 31,  9,  5, 11 } };

     RKISS rk;
     RKISS rk;

-    Bitboard occupancy[4096], proofs[4096], excluded;
+    Bitboard occupancy[4096], reference[4096], excluded;

     int key, maxKey, index, booster, offset = 0;
 
     for (Square s = SQ_A1; s <= SQ_H8; s++)
     {
         excluded = ((Rank1BB | Rank8BB) & ~rank_bb(s)) | ((FileABB | FileHBB) & ~file_bb(s));
 
     int key, maxKey, index, booster, offset = 0;
 
     for (Square s = SQ_A1; s <= SQ_H8; s++)
     {
         excluded = ((Rank1BB | Rank8BB) & ~rank_bb(s)) | ((FileABB | FileHBB) & ~file_bb(s));
 

-        attack[s] = &attTabl[offset];
-        mask[s]   = sliding_attacks(s, EmptyBoardBB, deltas, excluded);
+        attack[s] = &attTable[offset];
+        mask[s]   = sliding_attacks(s, EmptyBoardBB, delta, excluded);

         shift[s]  = (CpuIs64Bit ? 64 : 32) - count_1s<CNT64>(mask[s]);
 
         maxKey = 1 << count_1s<CNT32>(mask[s]);
         shift[s]  = (CpuIs64Bit ? 64 : 32) - count_1s<CNT64>(mask[s]);
 
         maxKey = 1 << count_1s<CNT32>(mask[s]);

-        booster = CpuIs64Bit ? MagicBoosters64[square_rank(s)] : MagicBoosters32[square_rank(s)];
+        offset += maxKey;
+        booster = MagicBoosters[CpuIs64Bit][square_rank(s)];

 
         // First compute occupancy and attacks for square 's'
         for (key = 0; key < maxKey; key++)
         {
             occupancy[key] = submask(mask[s], key);
 
         // First compute occupancy and attacks for square 's'
         for (key = 0; key < maxKey; key++)
         {
             occupancy[key] = submask(mask[s], key);

-            proofs[key] = sliding_attacks(s, occupancy[key], deltas, EmptyBoardBB);
+            reference[key] = sliding_attacks(s, occupancy[key], delta, EmptyBoardBB);

         }
 
         }
 

-        // Then find a possible magic and corresponding attacks
+        // Then find a possible magic and the corresponding attacks

         do {
             magic[s] = pick_magic<CpuIs64Bit>(mask[s], rk, booster);
             memset(attack[s], 0, maxKey * sizeof(Bitboard));
         do {
             magic[s] = pick_magic<CpuIs64Bit>(mask[s], rk, booster);
             memset(attack[s], 0, maxKey * sizeof(Bitboard));


@@ -353,14 +348,12 @@ namespace {
                                    : unsigned(occupancy[key] * magic[s] ^ (occupancy[key] >> 32) * (magic[s] >> 32)) >> shift[s];
 
                 if (!attack[s][index])
                                    : unsigned(occupancy[key] * magic[s] ^ (occupancy[key] >> 32) * (magic[s] >> 32)) >> shift[s];
 
                 if (!attack[s][index])

-                    attack[s][index] = proofs[key];
+                    attack[s][index] = reference[key];

 
 

-                else if (attack[s][index] != proofs[key])
+                else if (attack[s][index] != reference[key])

                     break;
             }
         } while (key != maxKey);
                     break;
             }
         } while (key != maxKey);

-
-        offset += maxKey;

     }
   }
 }
     }
   }
 }