X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbitbase.cpp;h=8d3b37c040a1a6f56f38fa1b897501d49b730b9c;hp=dbda28e0019cf9e161b826cd4130307f2db6cb97;hb=18375e3bfbd03b0851969bda5427d5b22cb4fea1;hpb=a646f74e6a62af756b2e51756a81ee983db4ff34
diff --git a/src/bitbase.cpp b/src/bitbase.cpp
index dbda28e0..8d3b37c0 100644
--- a/src/bitbase.cpp
+++ b/src/bitbase.cpp
@@ -1,7 +1,7 @@
/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, 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
@@ -17,7 +17,9 @@
along with this program. If not, see .
*/
+#include
#include
+#include
#include
#include "bitboard.h"
@@ -26,10 +28,10 @@
namespace {
// There are 24 possible pawn squares: the first 4 files and ranks from 2 to 7
- const unsigned IndexMax = 2*24*64*64; // stm * psq * wksq * bksq = 196608
+ const unsigned MAX_INDEX = 2*24*64*64; // stm * psq * wksq * bksq = 196608
// Each uint32_t stores results of 32 positions, one per bit
- uint32_t KPKBitbase[IndexMax / 32];
+ uint32_t KPKBitbase[MAX_INDEX / 32];
// A KPK bitbase index is an integer in [0, IndexMax] range
//
@@ -41,7 +43,7 @@ namespace {
// bit 13-14: white pawn file (from FILE_A to FILE_D)
// bit 15-17: white pawn RANK_7 - rank (from RANK_7 - RANK_7 to RANK_7 - RANK_2)
unsigned index(Color us, Square bksq, Square wksq, Square psq) {
- return wksq + (bksq << 6) + (us << 12) + (file_of(psq) << 13) + ((RANK_7 - rank_of(psq)) << 15);
+ return wksq | (bksq << 6) | (us << 12) | (file_of(psq) << 13) | ((RANK_7 - rank_of(psq)) << 15);
}
enum Result {
@@ -54,15 +56,15 @@ namespace {
inline Result& operator|=(Result& r, Result v) { return r = Result(r | v); }
struct KPKPosition {
-
+ KPKPosition() = default;
KPKPosition(unsigned idx);
operator Result() const { return result; }
Result classify(const std::vector& db)
{ return us == WHITE ? classify(db) : classify(db); }
- private:
template Result classify(const std::vector& db);
+ unsigned id;
Color us;
Square bksq, wksq, psq;
Result result;
@@ -71,7 +73,7 @@ namespace {
} // namespace
-bool Bitbases::probe_kpk(Square wksq, Square wpsq, Square bksq, Color us) {
+bool Bitbases::probe(Square wksq, Square wpsq, Square bksq, Color us) {
assert(file_of(wpsq) <= FILE_D);
@@ -80,26 +82,22 @@ bool Bitbases::probe_kpk(Square wksq, Square wpsq, Square bksq, Color us) {
}
-void Bitbases::init_kpk() {
+void Bitbases::init() {
- unsigned idx, repeat = 1;
- std::vector db;
- db.reserve(IndexMax);
+ std::vector db(MAX_INDEX);
// Initialize db with known win / draw positions
- for (idx = 0; idx < IndexMax; ++idx)
- db.push_back(KPKPosition(idx));
+ std::generate(db.begin(), db.end(), [](){ static unsigned id; return KPKPosition(id++); });
// Iterate through the positions until none of the unknown positions can be
// changed to either wins or draws (15 cycles needed).
- while (repeat)
- for (repeat = idx = 0; idx < IndexMax; ++idx)
- repeat |= (db[idx] == UNKNOWN && db[idx].classify(db) != UNKNOWN);
+ while (std::accumulate(db.begin(), db.end(), false, [&](bool repeat, KPKPosition& pos)
+ { return (pos == UNKNOWN && pos.classify(db) != UNKNOWN) || repeat; }));
// Map 32 results into one KPKBitbase[] entry
- for (idx = 0; idx < IndexMax; ++idx)
- if (db[idx] == WIN)
- KPKBitbase[idx / 32] |= 1 << (idx & 0x1F);
+ for (auto& pos : db)
+ if (pos == WIN)
+ KPKBitbase[pos.id / 32] |= 1 << (pos.id & 0x1F);
}
@@ -107,14 +105,17 @@ namespace {
KPKPosition::KPKPosition(unsigned idx) {
- wksq = Square((idx >> 0) & 0x3F);
- bksq = Square((idx >> 6) & 0x3F);
- us = Color ((idx >> 12) & 0x01);
- psq = File ((idx >> 13) & 0x03) | Rank(RANK_7 - (idx >> 15));
- result = UNKNOWN;
+ id = idx;
+ wksq = Square((idx >> 0) & 0x3F);
+ bksq = Square((idx >> 6) & 0x3F);
+ us = Color ((idx >> 12) & 0x01);
+ psq = make_square(File((idx >> 13) & 0x3), RANK_7 - Rank((idx >> 15) & 0x7));
+ result = UNKNOWN;
// Check if two pieces are on the same square or if a king can be captured
- if ( square_distance(wksq, bksq) <= 1 || wksq == psq || bksq == psq
+ if ( distance(wksq, bksq) <= 1
+ || wksq == psq
+ || bksq == psq
|| (us == WHITE && (StepAttacksBB[PAWN][psq] & bksq)))
result = INVALID;
@@ -123,7 +124,7 @@ namespace {
// Immediate win if a pawn can be promoted without getting captured
if ( rank_of(psq) == RANK_7
&& wksq != psq + DELTA_N
- && ( square_distance(bksq, psq + DELTA_N) > 1
+ && ( distance(bksq, psq + DELTA_N) > 1
||(StepAttacksBB[KING][wksq] & (psq + DELTA_N))))
result = WIN;
}
@@ -146,7 +147,9 @@ namespace {
// as WIN, the position is classified as WIN, otherwise the current position is
// classified as UNKNOWN.
- const Color Them = (Us == WHITE ? BLACK : WHITE);
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
+ const Result Good = (Us == WHITE ? WIN : DRAW);
+ const Result Bad = (Us == WHITE ? DRAW : WIN);
Result r = INVALID;
Bitboard b = StepAttacksBB[KING][Us == WHITE ? wksq : bksq];
@@ -164,10 +167,7 @@ namespace {
r |= db[index(BLACK, bksq, wksq, s + DELTA_N)]; // Double push
}
- if (Us == WHITE)
- return result = r & WIN ? WIN : r & UNKNOWN ? UNKNOWN : DRAW;
- else
- return result = r & DRAW ? DRAW : r & UNKNOWN ? UNKNOWN : WIN;
+ return result = r & Good ? Good : r & UNKNOWN ? UNKNOWN : Bad;
}
} // namespace