X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbitbase.cpp;h=a018d3cdad7a087ee973238f495c4c8d7e46d5a2;hp=ebf3c59a02355d780e31d79b48d8e70c36ee7d6c;hb=3017e8c60401ecd92468a9ede3368002c4ddd440;hpb=69407ae9b88d9fd7e8b724f1a8bf1f47bb4d2f67
diff --git a/src/bitbase.cpp b/src/bitbase.cpp
index ebf3c59a..a018d3cd 100644
--- a/src/bitbase.cpp
+++ b/src/bitbase.cpp
@@ -17,9 +17,7 @@
along with this program. If not, see .
*/
-#include
#include
-#include
#include
#include "bitboard.h"
@@ -56,17 +54,17 @@ namespace {
inline Result& operator|=(Result& r, Result v) { return r = Result(r | v); }
struct KPKPosition {
- KPKPosition() = default;
- explicit KPKPosition(unsigned idx);
+
+ 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 ksq[COLOR_NB], psq;
+ Square bksq, wksq, psq;
Result result;
};
@@ -84,20 +82,24 @@ bool Bitbases::probe(Square wksq, Square wpsq, Square bksq, Color us) {
void Bitbases::init() {
- std::vector db(MAX_INDEX);
+ unsigned idx, repeat = 1;
+ std::vector db;
+ db.reserve(MAX_INDEX);
// 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.push_back(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);
}
@@ -105,74 +107,69 @@ 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));
+ 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 ( distance(ksq[WHITE], ksq[BLACK]) <= 1
- || ksq[WHITE] == psq
- || ksq[BLACK] == psq
- || (us == WHITE && (StepAttacksBB[PAWN][psq] & ksq[BLACK])))
+ if ( distance(wksq, bksq) <= 1
+ || wksq == psq
+ || bksq == psq
+ || (us == WHITE && (StepAttacksBB[PAWN][psq] & bksq)))
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))))
- result = WIN;
-
+ else if (us == WHITE)
+ {
+ // Immediate win if a pawn can be promoted without getting captured
+ if ( rank_of(psq) == RANK_7
+ && wksq != psq + DELTA_N
+ && ( distance(bksq, psq + DELTA_N) > 1
+ ||(StepAttacksBB[KING][wksq] & (psq + DELTA_N))))
+ 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]])))
+ else if ( !(StepAttacksBB[KING][bksq] & ~(StepAttacksBB[KING][wksq] | StepAttacksBB[PAWN][psq]))
+ || (StepAttacksBB[KING][bksq] & psq & ~StepAttacksBB[KING][wksq]))
result = DRAW;
-
- // Position will be classified later
- else
- result = UNKNOWN;
}
template
Result KPKPosition::classify(const std::vector& db) {
- // White to move: If one move leads to a position classified as WIN, the result
+ // White to Move: If one move leads to a position classified as WIN, the result
// of the current position is WIN. If all moves lead to positions classified
// as DRAW, the current position is classified as DRAW, otherwise the current
// position is classified as UNKNOWN.
//
- // Black to move: If one move leads to a position classified as DRAW, the result
+ // Black to Move: If one move leads to a position classified as DRAW, the result
// of the current position is DRAW. If all moves lead to positions classified
// 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);
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
Result r = INVALID;
- Bitboard b = StepAttacksBB[KING][ksq[Us]];
+ Bitboard b = StepAttacksBB[KING][Us == WHITE ? wksq : bksq];
while (b)
- r |= Us == WHITE ? db[index(Them, ksq[Them] , pop_lsb(&b), psq)]
- : db[index(Them, pop_lsb(&b), ksq[Them] , psq)];
+ r |= Us == WHITE ? db[index(Them, bksq, pop_lsb(&b), psq)]
+ : db[index(Them, pop_lsb(&b), wksq, psq)];
- if (Us == WHITE)
+ if (Us == WHITE && rank_of(psq) < RANK_7)
{
- if (rank_of(psq) < RANK_7) // Single push
- r |= db[index(Them, ksq[Them], ksq[Us], psq + DELTA_N)];
+ Square s = psq + DELTA_N;
+ r |= db[index(BLACK, bksq, wksq, s)]; // Single push
- 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)];
+ if (rank_of(psq) == RANK_2 && s != wksq && s != bksq)
+ r |= db[index(BLACK, bksq, wksq, s + DELTA_N)]; // Double push
}
- return result = r & Good ? Good : r & UNKNOWN ? UNKNOWN : Bad;
+ if (Us == WHITE)
+ return result = r & WIN ? WIN : r & UNKNOWN ? UNKNOWN : DRAW;
+ else
+ return result = r & DRAW ? DRAW : r & UNKNOWN ? UNKNOWN : WIN;
}
} // namespace