X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbitboard.cpp;h=e329ab52a79439710ef1771ecc4ac3be08442c0b;hp=7a4d73c9cb6b2adbbbd8204777327d5311201375;hb=e0504ab876a997321102f040ab88203cb893db12;hpb=84a641b8bb849a1951c60f92dc97619237fb2d09

diff --git a/src/bitboard.cpp b/src/bitboard.cpp
index 7a4d73c9..e329ab52 100644
--- a/src/bitboard.cpp
+++ b/src/bitboard.cpp
@@ -2,6 +2,7 @@
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
   Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
+  Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -20,9 +21,9 @@
 #include <algorithm>
 
 #include "bitboard.h"
-#include "bitcount.h"
 #include "misc.h"
 
+uint8_t PopCnt16[1 << 16];
 int SquareDistance[SQUARE_NB][SQUARE_NB];
 
 Bitboard  RookMasks  [SQUARE_NB];
@@ -73,18 +74,30 @@ namespace {
     return Is64Bit ? (b * DeBruijn64) >> 58
                    : ((unsigned(b) ^ unsigned(b >> 32)) * DeBruijn32) >> 26;
   }
+
+
+  // popcount16() counts the non-zero bits using SWAR-Popcount algorithm
+
+  unsigned popcount16(unsigned u) {
+    u -= (u >> 1) & 0x5555U;
+    u = ((u >> 2) & 0x3333U) + (u & 0x3333U);
+    u = ((u >> 4) + u) & 0x0F0FU;
+    return (u * 0x0101U) >> 8;
+  }
 }
 
-#ifndef USE_BSFQ
+#ifdef NO_BSF
 
 /// Software fall-back of lsb() and msb() for CPU lacking hardware support
 
 Square lsb(Bitboard b) {
+  assert(b);
   return BSFTable[bsf_index(b)];
 }
 
 Square msb(Bitboard b) {
 
+  assert(b);
   unsigned b32;
   int result = 0;
 
@@ -111,7 +124,7 @@ Square msb(Bitboard b) {
   return Square(result + MSBTable[b32]);
 }
 
-#endif // ifndef USE_BSFQ
+#endif // ifdef NO_BSF
 
 
 /// Bitboards::pretty() returns an ASCII representation of a bitboard suitable
@@ -138,6 +151,9 @@ const std::string Bitboards::pretty(Bitboard b) {
 
 void Bitboards::init() {
 
+  for (unsigned i = 0; i < (1 << 16); ++i)
+      PopCnt16[i] = (uint8_t) popcount16(i);
+
   for (Square s = SQ_A1; s <= SQ_H8; ++s)
   {
       SquareBB[s] = 1ULL << s;
@@ -189,8 +205,8 @@ void Bitboards::init() {
                       StepAttacksBB[make_piece(c, pt)][s] |= to;
               }
 
-  Square RookDeltas[] = { DELTA_N,  DELTA_E,  DELTA_S,  DELTA_W  };
-  Square BishopDeltas[] = { DELTA_NE, DELTA_SE, DELTA_SW, DELTA_NW };
+  Square RookDeltas[] = { NORTH,  EAST,  SOUTH,  WEST  };
+  Square BishopDeltas[] = { NORTH_EAST, SOUTH_EAST, SOUTH_WEST, NORTH_WEST };
 
   init_magics(RookTable, RookAttacks, RookMagics, RookMasks, RookShifts, RookDeltas, magic_index<ROOK>);
   init_magics(BishopTable, BishopAttacks, BishopMagics, BishopMasks, BishopShifts, BishopDeltas, magic_index<BISHOP>);
@@ -262,7 +278,7 @@ namespace {
         // the number of 1s of the mask. Hence we deduce the size of the shift to
         // apply to the 64 or 32 bits word to get the index.
         masks[s]  = sliding_attack(deltas, s, 0) & ~edges;
-        shifts[s] = (Is64Bit ? 64 : 32) - popcount<Max15>(masks[s]);
+        shifts[s] = (Is64Bit ? 64 : 32) - popcount(masks[s]);
 
         // Use Carry-Rippler trick to enumerate all subsets of masks[s] and
         // store the corresponding sliding attack bitboard in reference[].
@@ -293,7 +309,7 @@ namespace {
         do {
             do
                 magics[s] = rng.sparse_rand<Bitboard>();
-            while (popcount<Max15>((magics[s] * masks[s]) >> 56) < 6);
+            while (popcount((magics[s] * masks[s]) >> 56) < 6);
 
             // A good magic must map every possible occupancy to an index that
             // looks up the correct sliding attack in the attacks[s] database.