X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbitbase.cpp;h=8c8c47020bb2678d74ddc45628bd87f152e6ff88;hp=ebf3c59a02355d780e31d79b48d8e70c36ee7d6c;hb=c8589903777b6e0289640b43fae966ded442af48;hpb=f6f1d2422303923927c0c088dee1d6df22dc4b98
diff --git a/src/bitbase.cpp b/src/bitbase.cpp
index ebf3c59a..8c8c4702 100644
--- a/src/bitbase.cpp
+++ b/src/bitbase.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) 2015-2019 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
@@ -17,7 +18,6 @@
along with this program. If not, see .
*/
-#include
#include
#include
#include
@@ -28,7 +28,7 @@
namespace {
// There are 24 possible pawn squares: the first 4 files and ranks from 2 to 7
- const unsigned MAX_INDEX = 2*24*64*64; // stm * psq * wksq * bksq = 196608
+ constexpr 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[MAX_INDEX / 32];
@@ -53,7 +53,7 @@ namespace {
WIN = 4
};
- inline Result& operator|=(Result& r, Result v) { return r = Result(r | v); }
+ Result& operator|=(Result& r, Result v) { return r = Result(r | v); }
struct KPKPosition {
KPKPosition() = default;
@@ -64,7 +64,6 @@ namespace {
template Result classify(const std::vector& db);
- unsigned id;
Color us;
Square ksq[COLOR_NB], psq;
Result result;
@@ -85,19 +84,22 @@ bool Bitbases::probe(Square wksq, Square wpsq, Square bksq, Color us) {
void Bitbases::init() {
std::vector db(MAX_INDEX);
+ unsigned idx, repeat = 1;
// Initialize db with known win / draw positions
- std::generate(db.begin(), db.end(), [](){ static unsigned id; return KPKPosition(id++); });
+ for (idx = 0; idx < MAX_INDEX; ++idx)
+ db[idx] = KPKPosition(idx);
// Iterate through the positions until none of the unknown positions can be
// changed to either wins or draws (15 cycles needed).
- while (std::accumulate(db.begin(), db.end(), false, [&](bool repeat, KPKPosition& pos)
- { return (pos == UNKNOWN && pos.classify(db) != UNKNOWN) || repeat; })){}
+ while (repeat)
+ for (repeat = idx = 0; idx < MAX_INDEX; ++idx)
+ repeat |= (db[idx] == UNKNOWN && db[idx].classify(db) != UNKNOWN);
// Map 32 results into one KPKBitbase[] entry
- for (auto& pos : db)
- if (pos == WIN)
- KPKBitbase[pos.id / 32] |= 1 << (pos.id & 0x1F);
+ for (idx = 0; idx < MAX_INDEX; ++idx)
+ if (db[idx] == WIN)
+ KPKBitbase[idx / 32] |= 1 << (idx & 0x1F);
}
@@ -105,31 +107,30 @@ namespace {
KPKPosition::KPKPosition(unsigned idx) {
- id = idx;
ksq[WHITE] = Square((idx >> 0) & 0x3F);
ksq[BLACK] = Square((idx >> 6) & 0x3F);
us = Color ((idx >> 12) & 0x01);
- psq = make_square(File((idx >> 13) & 0x3), RANK_7 - Rank((idx >> 15) & 0x7));
+ psq = make_square(File((idx >> 13) & 0x3), Rank(RANK_7 - ((idx >> 15) & 0x7)));
// Check if two pieces are on the same square or if a king can be captured
if ( distance(ksq[WHITE], ksq[BLACK]) <= 1
|| ksq[WHITE] == psq
|| ksq[BLACK] == psq
- || (us == WHITE && (StepAttacksBB[PAWN][psq] & ksq[BLACK])))
+ || (us == WHITE && (PawnAttacks[WHITE][psq] & ksq[BLACK])))
result = INVALID;
// Immediate win if a pawn can be promoted without getting captured
else if ( us == WHITE
&& rank_of(psq) == RANK_7
- && ksq[us] != psq + DELTA_N
- && ( distance(ksq[~us], psq + DELTA_N) > 1
- || (StepAttacksBB[KING][ksq[us]] & (psq + DELTA_N))))
+ && ksq[us] != psq + NORTH
+ && ( distance(ksq[~us], psq + NORTH) > 1
+ || (PseudoAttacks[KING][ksq[us]] & (psq + NORTH))))
result = WIN;
// Immediate draw if it is a stalemate or a king captures undefended pawn
else if ( us == BLACK
- && ( !(StepAttacksBB[KING][ksq[us]] & ~(StepAttacksBB[KING][ksq[~us]] | StepAttacksBB[PAWN][psq]))
- || (StepAttacksBB[KING][ksq[us]] & psq & ~StepAttacksBB[KING][ksq[~us]])))
+ && ( !(PseudoAttacks[KING][ksq[us]] & ~(PseudoAttacks[KING][ksq[~us]] | PawnAttacks[~us][psq]))
+ || (PseudoAttacks[KING][ksq[us]] & psq & ~PseudoAttacks[KING][ksq[~us]])))
result = DRAW;
// Position will be classified later
@@ -150,12 +151,12 @@ 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 Result Good = (Us == WHITE ? WIN : DRAW);
- const Result Bad = (Us == WHITE ? DRAW : WIN);
+ constexpr Color Them = (Us == WHITE ? BLACK : WHITE);
+ constexpr Result Good = (Us == WHITE ? WIN : DRAW);
+ constexpr Result Bad = (Us == WHITE ? DRAW : WIN);
Result r = INVALID;
- Bitboard b = StepAttacksBB[KING][ksq[Us]];
+ Bitboard b = PseudoAttacks[KING][ksq[Us]];
while (b)
r |= Us == WHITE ? db[index(Them, ksq[Them] , pop_lsb(&b), psq)]
@@ -164,12 +165,12 @@ namespace {
if (Us == WHITE)
{
if (rank_of(psq) < RANK_7) // Single push
- r |= db[index(Them, ksq[Them], ksq[Us], psq + DELTA_N)];
+ r |= db[index(Them, ksq[Them], ksq[Us], psq + NORTH)];
if ( rank_of(psq) == RANK_2 // Double push
- && psq + DELTA_N != ksq[Us]
- && psq + DELTA_N != ksq[Them])
- r |= db[index(Them, ksq[Them], ksq[Us], psq + DELTA_N + DELTA_N)];
+ && psq + NORTH != ksq[Us]
+ && psq + NORTH != ksq[Them])
+ r |= db[index(Them, ksq[Them], ksq[Us], psq + NORTH + NORTH)];
}
return result = r & Good ? Good : r & UNKNOWN ? UNKNOWN : Bad;