X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fbitbase.cpp;h=752d4f0e79c0b480b56697622c538600ec467951;hp=c6dab410dc007d41ef19d4ad6515285247a41db9;hb=8ca80cb0f1bb50f982f89efd147c45f9b91358a5;hpb=500b9b0eb3b20ef58ff1280a089ab2ef1e3c6436 diff --git a/src/bitbase.cpp b/src/bitbase.cpp index c6dab410..752d4f0e 100644 --- a/src/bitbase.cpp +++ b/src/bitbase.cpp @@ -25,7 +25,7 @@ namespace { - // The possible pawns squares are 24, the first 4 files and ranks from 2 to 7 + // 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 // Each uint32_t stores results of 32 positions, one per bit @@ -90,7 +90,7 @@ void Bitbases::init_kpk() { for (idx = 0; idx < IndexMax; ++idx) db.push_back(KPKPosition(idx)); - // Iterate through the positions until no more of the unknown positions can be + // 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) @@ -120,14 +120,14 @@ namespace { else if (us == WHITE) { - // Immediate win if pawn can be promoted without getting captured + // 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 ||(StepAttacksBB[KING][wksq] & (psq + DELTA_N)))) result = WIN; } - // Immediate draw if it is stalemate or king captures undefended pawn + // Immediate draw if it is a stalemate or a king captures undefended pawn else if ( !(StepAttacksBB[KING][bksq] & ~(StepAttacksBB[KING][wksq] | StepAttacksBB[PAWN][psq])) || (StepAttacksBB[KING][bksq] & psq & ~StepAttacksBB[KING][wksq])) result = DRAW; @@ -138,13 +138,13 @@ namespace { // 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 DRAW otherwise the current + // 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 // of the current position is DRAW. If all moves lead to positions classified - // as WIN, the position is classified WIN otherwise the current position is - // classified UNKNOWN. + // as WIN, the position is classified as WIN, otherwise the current position is + // classified as UNKNOWN. const Color Them = (Us == WHITE ? BLACK : WHITE);