gnuchess.c

早期freebsd实现

    }
  else if (piece == queen)
    {
      if (stage > 2) s += 14 - taxicab(sq,EnemyKing);
      if (distance(sq,EnemyKing) < 3) s += 12;
    }
  else if (piece == king)
    {
      s = Mking[c1][sq];
      if (KSFTY > 0)
        if (Developed[c2] || stage > 0) KingScan(sq,&s);
      if (castld[c1]) s += KCASTLD;
      else if (kingmoved[c1]) s += KMOVD;

      if (PC1[fyle] == 0) s += KHOPN;
      if (PC2[fyle] == 0) s += KHOPNX;
      if (fyle == 1 || fyle == 2 || fyle == 3 || fyle == 7)
        {
          if (PC1[fyle-1] == 0) s += KHOPN;
          if (PC2[fyle-1] == 0) s += KHOPNX;
        }
      if (fyle == 4 || fyle == 5 || fyle == 6 || fyle == 0)
        {
          if (PC1[fyle+1] == 0) s += KHOPN;
          if (PC2[fyle+1] == 0) s += KHOPNX;
        }
      if (fyle == 2)
        {
          if (PC1[0] == 0) s += KHOPN;
          if (PC2[0] == 0) s += KHOPNX;
        }
      if (fyle == 5)
        {
          if (PC1[7] == 0) s += KHOPN;
          if (PC2[7] == 0) s += KHOPNX;
        }
    }
    
  if (a2 > 0) 
    {
      c = (control[piece] & 0x4FFF);
      if (a1 == 0 || a2 > c+1)
        {
          s += HUNGP;
          ++hung[c1];
          if (piece != king && trapped(sq,piece)) ++hung[c1];
        }
      else if (piece != pawn || a2 > a1)
        if (a2 >= c || a1 < ctlP) s += ATAKD;
    }
  return(s);
}

#if (NEWMOVE > 6)
KingScan(sq,s)
short sq,*s;

/*
   Assign penalties if king can be threatened by checks, if squares
   near the king are controlled by the enemy (especially the queen),
   or if there are no pawns near the king.
*/

#define ScoreThreat\
  if (color[u] != c2)\
    if (atk1[u] == 0 || (atk2[u] & 0xFF) > 1) ++cnt;\
    else *s -= 3

{
register short m,u;
short d,i,m0,cnt,ok;

  cnt = 0;
  m0 = map[sq];
  if (HasBishop[c2] || HasQueen[c2])
    for (i = Dstart[bishop]; i <= Dstop[bishop]; i++)
      {
        d = Dir[i]; m = m0+d;
        while (!(m & 0x88))
          {
            u = unmap[m];
            if (atk2[u] & ctlBQ) ScoreThreat;
            if (color[u] != neutral) break;
            m += d;
          }
      }
  if (HasRook[c2] || HasQueen[c2])
    for (i = Dstart[rook]; i <= Dstop[rook]; i++)
      {
        d = Dir[i]; m = m0+d;
        while (!(m & 0x88))
          {
            u = unmap[m];
            if (atk2[u] & ctlRQ) ScoreThreat;
            if (color[u] != neutral) break;
            m += d;
          }
      }
  if (HasKnight[c2])
    for (i = Dstart[knight]; i <= Dstop[knight]; i++)
      if (!((m = m0+Dir[i]) & 0x88))
        {
          u = unmap[m];
          if (atk2[u] & ctlNN) ScoreThreat;
        }
  *s += (KSFTY*Kthreat[cnt]) / 16;

  cnt = 0; ok = false;
  m0 = map[sq];
  for (i = Dstart[king]; i <= Dstop[king]; i++)
    if (!((m = m0+Dir[i]) & 0x88))
      {
        u = unmap[m];
        if (board[u] == pawn) ok = true;
        if (atk2[u] > atk1[u])
          {
            ++cnt;
            if (atk2[u] & ctlQ)
              if (atk2[u] > ctlQ+1 && atk1[u] < ctlQ) *s -= 4*KSFTY;
          }
      }
  if (!ok) *s -= KSFTY;
  if (cnt > 1) *s -= KSFTY;
}
#endif

#if (NEWMOVE < 4)
BRscan(sq,s,mob)
short sq,*s,*mob;

/*
   Find Bishop and Rook mobility, XRAY attacks, and pins. Increment the 
   hung[] array if a pin is found. 
*/

{
register short m,u;
short d,j,m0,piece,pin,*Kf;

  Kf = Kfield[c1];
  *mob = 0;
  m0 = map[sq]; piece = board[sq];
  for (j = Dstart[piece]; j <= Dstop[piece]; j++)
    {
      pin = -1;
      d = Dir[j]; m = m0+d;
      while (!(m & 0x88))
        {
          u = unmap[m]; *s += Kf[u];
          if (color[u] == neutral)
            {
              (*mob)++;
              m += d;
            }
          else if (pin < 0)
            {
              if (board[u] == pawn || board[u] == king) break;
              pin = u;
              m += d;
            }
          else if (color[u] == c2 && (board[u] > piece || atk2[u] == 0))
            {
              if (color[pin] == c2)
                {
                  *s += PINVAL;
                  if (atk2[pin] == 0 ||
                      atk1[pin] > control[board[pin]]+1)
                    ++hung[c2];
                }
              else *s += XRAY;
              break;
            }
          else break;
        }
    }
}
#endif

#if (NEWMOVE > 5)
int trapped(sq,piece)
short sq,piece;

/*
   See if the attacked piece has unattacked squares to move to.
*/

{
register short u,m,d;
short i,m0;

  m0 = map[sq];
  if (sweep[piece])
    for (i = Dstart[piece]; i <= Dstop[piece]; i++)
      {
        d = Dir[i]; m = m0+d;
        while (!(m & 0x88))
          {
            u = unmap[m];
            if (color[u] == c1) break;
            if (atk2[u] == 0 || board[u] >= piece) return(false);
            if (color[u] == c2) break;
            m += d;
          }
      }
  else if (piece == pawn)
    {
      if (c1 == white) u = sq+8; else u = sq-8;
      if (color[u] == neutral && atk1[u] >= atk2[u])
        return(false);
      if (!((m = m0+Dir[Dpwn[c1]]) & 0x88))
        if (color[unmap[m]] == c2) return(false);
      if (!((m = m0+Dir[Dpwn[c1]+1]) & 0x88))
        if (color[unmap[m]] == c2) return(false);
    }
  else
    {
      for (i = Dstart[piece]; i <= Dstop[piece]; i++)
        if (!((m = m0+Dir[i]) & 0x88))
          {
            u = unmap[m];
            if (color[u] != c1)
              if (atk2[u] == 0 || board[u] >= piece) return(false);
          }
    }
  return(true);
}
#endif

ExaminePosition()

/*
   This is done one time before the search is started. Set up arrays 
   Mwpawn, Mbpawn, Mknight, Mbishop, Mking which are used in the 
   SqValue() function to determine the positional value of each piece. 
*/

{
register short i,sq;
short wpadv,bpadv,wstrong,bstrong,z,side,pp,j,val,Pd,fyle,rank;

  wking = PieceList[white][0]; bking = PieceList[black][0];
  ataks(white,atak[white]); ataks(black,atak[black]);
  Zwmtl = Zbmtl = 0;
  UpdateWeights();
  HasPawn[white] = HasPawn[black] = 0;
  HasKnight[white] = HasKnight[black] = 0;
  HasBishop[white] = HasBishop[black] = 0;
  HasRook[white] = HasRook[black] = 0;
  HasQueen[white] = HasQueen[black] = 0;
  for (side = white; side <= black; side++)
    for (i = 0; i <= PieceCnt[side]; i++)
      switch (board[PieceList[side][i]])
        {
          case pawn : ++HasPawn[side]; break;
          case knight : ++HasKnight[side]; break;
          case bishop : ++HasBishop[side]; break;
          case rook : ++HasRook[side]; break;
          case queen : ++HasQueen[side]; break;
        }
  if (!Developed[white])
    Developed[white] = (board[1] != knight && board[2] != bishop &&
                        board[5] != bishop && board[6] != knight);
  if (!Developed[black])
    Developed[black] = (board[57] != knight && board[58] != bishop &&
                        board[61] != bishop && board[62] != knight);
  if (!PawnStorm && stage < 5)
    PawnStorm = ((column[wking] < 3 && column[bking] > 4) ||
                 (column[wking] > 4 && column[bking] < 3));
  
  CopyBoard(pknight,Mknight[white]);
  CopyBoard(pknight,Mknight[black]);
  CopyBoard(pbishop,Mbishop[white]);
  CopyBoard(pbishop,Mbishop[black]);
  BlendBoard(KingOpening,KingEnding,Mking[white]);
  BlendBoard(KingOpening,KingEnding,Mking[black]);
  
  for (sq = 0; sq < 64; sq++)
    {
      fyle = column[sq]; rank = row[sq];
      wstrong = bstrong = true;
      for (i = sq; i < 64; i += 8)
        if (atak[black][i] >= ctlP) wstrong = false;
      for (i = sq; i >= 0; i -= 8)
        if (atak[white][i] >= ctlP) bstrong = false;
      wpadv = bpadv = PADVNCM;
      if ((fyle == 0 || PawnCnt[white][fyle-1] == 0) &&
          (fyle == 7 || PawnCnt[white][fyle+1] == 0)) wpadv = PADVNCI;
      if ((fyle == 0 || PawnCnt[black][fyle-1] == 0) &&
          (fyle == 7 || PawnCnt[black][fyle+1] == 0)) bpadv = PADVNCI;
      Mwpawn[sq] = (wpadv*PawnAdvance[sq]) / 10;
      Mbpawn[sq] = (bpadv*PawnAdvance[63-sq]) / 10;
      Mwpawn[sq] += PawnBonus; Mbpawn[sq] += PawnBonus;
      if (castld[white] || kingmoved[white])
        {
          if ((fyle < 3 || fyle > 4) && distance(sq,wking) < 3)
            Mwpawn[sq] += PAWNSHIELD;
        }
      else if (rank < 3 && (fyle < 2 || fyle > 5))
        Mwpawn[sq] += PAWNSHIELD / 2;
      if (castld[black] || kingmoved[black])
        {
          if ((fyle < 3 || fyle > 4) && distance(sq,bking) < 3)
            Mbpawn[sq] += PAWNSHIELD;
        }
      else if (rank > 4 && (fyle < 2 || fyle > 5))
        Mbpawn[sq] += PAWNSHIELD / 2;
      if (PawnStorm)
        {
          if ((column[wking] < 4 && fyle > 4) ||
              (column[wking] > 3 && fyle < 3)) Mwpawn[sq] += 3*rank - 21;
          if ((column[bking] < 4 && fyle > 4) ||
              (column[bking] > 3 && fyle < 3)) Mbpawn[sq] -= 3*rank;
        }
        
      Mknight[white][sq] += 5 - distance(sq,bking);
      Mknight[white][sq] += 5 - distance(sq,wking);
      Mknight[black][sq] += 5 - distance(sq,wking);
      Mknight[black][sq] += 5 - distance(sq,bking);
      Mbishop[white][sq] += BishopBonus;
      Mbishop[black][sq] += BishopBonus;
      for (i = 0; i <= PieceCnt[black]; i++)
        if (distance(sq,PieceList[black][i]) < 3)
          Mknight[white][sq] += KNIGHTPOST;
      for (i = 0; i <= PieceCnt[white]; i++)
        if (distance(sq,PieceList[white][i]) < 3)
          Mknight[black][sq] += KNIGHTPOST;
      if (wstrong) Mknight[white][sq] += KNIGHTSTRONG;
      if (bstrong) Mknight[black][sq] += KNIGHTSTRONG;
      if (wstrong) Mbishop[white][sq] += BISHOPSTRONG;
      if (bstrong) Mbishop[black][sq] += BISHOPSTRONG;
      
      if (HasBishop[white] == 2) Mbishop[white][sq] += 8;
      if (HasBishop[black] == 2) Mbishop[black][sq] += 8;
      if (HasKnight[white] == 2) Mknight[white][sq] += 5;
      if (HasKnight[black] == 2) Mknight[black][sq] += 5;
      
      if (board[sq] == bishop)
        if (rank % 2 == fyle % 2) KBNKsq = 0; else KBNKsq = 7;
        
      Kfield[white][sq] = Kfield[black][sq] = 0;
      if (distance(sq,wking) == 1) Kfield[black][sq] = KATAK;
      if (distance(sq,bking) == 1) Kfield[white][sq] = KATAK;
      
      Pd = 0;
      for (i = 0; i < 64; i++)
        if (board[i] == pawn)
          {
            if (color[i] == white)
              {
                pp = true;
                if (row[i] == 6) z = i+8; else z = i+16;
                for (j = i+8; j < 64; j += 8)
                  if (atak[black][j] > ctlP || board[j] == pawn) pp = false;
              }
            else
              {
                pp = true;
                if (row[i] == 1) z = i-8; else z = i-16;
                for (j = i-8; j >= 0; j -= 8)
                  if (atak[white][j] > ctlP || board[j] == pawn) pp = false;
              }
            if (pp) Pd += 5*taxicab(sq,z); else Pd += taxicab(sq,z);
          }
      if (Pd != 0)
        {
          val = (Pd*stage2) / 10;
          Mking[white][sq] -= val;
          Mking[black][sq] -= val;
        }
    }
}


UpdateWeights()

/* 
   If material balance has changed, determine the values for the 
   positional evaluation terms. 
*/

{
short tmtl;

  if (mtl[white] != Zwmtl || mtl[black] != Zbmtl)
    {
      Zwmtl = mtl[white]; Zbmtl = mtl[black];
      emtl[white] = Zwmtl - pmtl[white] - valueK;
      emtl[black] = Zbmtl - pmtl[black] - valueK;
      tmtl = emtl[white] + emtl[black];
      if (tmtl > 6600) stage = 0;
      else if (tmtl < 1400) stage = 10;
      else stage = (6600-tmtl) / 520;
      if (tmtl > 3600) stage2 = 0;
      else if (tmtl < 1400) stage2 = 10;
      else stage2 = (3600-tmtl) / 220;
      
      PEDRNK2B = -15;         /* centre pawn on 2nd rank & blocked */
      PBLOK = -4;             /* blocked backward pawn */
      PDOUBLED = -14;         /* doubled pawn */
      PWEAKH  = -4;           /* weak pawn on half open file */
      PAWNSHIELD = 10-stage;  /* pawn near friendly king */
      PADVNCM =  10;          /* advanced pawn multiplier */
      PADVNCI = 7;            /* muliplier for isolated pawn */
      PawnBonus = stage;
      
      KNIGHTPOST = (stage+2)/3;   /* knight near enemy pieces */
      KNIGHTSTRONG = (stage+6)/2; /* occupies pawn hole */
      
      BISHOPSTRONG = (stage+6)/2; /* occupies pawn hole */
      BishopBonus = 2*stage;
      
      RHOPN    = 10;          /* rook on half open file */
      RHOPNX   = 4;
      RookBonus = 6*stage;
      
      XRAY     = 8;           /* Xray attack on piece */
      PINVAL   = 10;          /* Pin */
      
      KHOPN    = (3*stage-30) / 2; /* king on half open file */
      KHOPNX   = KHOPN / 2;
      KCASTLD  = 10 - stage;
      KMOVD    = -40 / (stage+1);  /* king moved before castling */
      KATAK    = (10-stage) / 2;   /* B,R attacks near enemy king */
      if (stage < 8) KSFTY = 16-2*stage; else KSFTY = 0;
      
      ATAKD    = -6;          /* defender > attacker */
      HUNGP    = -8;          /* each hung piece */
      HUNGX    = -12;         /* extra for >1 hung piece */
    }
}

#if (NEWMOVE < 1)
int distance(a,b)
short a,b;
{
register short d1,d2;

  d1 = abs(column[a]-column[b]);
  d2 = abs(row[a]-row[b]);
  return(d1 > d2 ? d1 : d2);
}
#endif

BlendBoard(a,b,c)
short a[64],b[64],c[64];
{
register int sq;
  for (sq = 0; sq < 64; sq++)
    c[sq] = (a[sq]*(10-stage) + b[sq]*stage) / 10;
}


CopyBoard(a,b)
short a[64],b[64];
{
register int sq;
  for (sq = 0; sq < 64; sq++)
    b[sq] = a[sq];
}