/**
* Get a score for move m based on hits in the killer table.
* The score is 4 for primary hit at ply.
* The score is 3 for secondary hit at ply.
* The score is 2 for primary hit at ply - 2.
* The score is 1 for secondary hit at ply - 2.
* The score is 0 otherwise.
*/
public int getKillerScore(int ply, Move m)
{
int move = (short)(m.from + (m.to << 6) + (m.promoteTo << 12));
if (ply < ktList.Length)
{
KTEntry ent = ktList[ply];
if (move == ent.move0)
{
return(4);
}
else if (move == ent.move1)
{
return(3);
}
}
if ((ply - 2 >= 0) && (ply - 2 < ktList.Length))
{
KTEntry ent = ktList[ply - 2];
if (move == ent.move0)
{
return(2);
}
else if (move == ent.move1)
{
return(1);
}
}
return(0);
}
/** Create an empty killer table. */
public KillerTable()
{
ktList = new KTEntry[200];
for (int i = 0; i < ktList.Length; i++)
{
ktList[i] = new KTEntry();
}
}
/** Add a killer move to the table. Moves are replaced on an LRU basis. */
public void addKiller(int ply, Move m)
{
if (ply >= ktList.Length)
{
return;
}
int move = (short)(m.from + (m.to << 6) + (m.promoteTo << 12));
KTEntry ent = ktList[ply];
if (move != ent.move0)
{
ent.move1 = ent.move0;
ent.move0 = move;
}
}
/** Create an empty killer table. */
public KillerTable()
{
ktList = new KTEntry[200];
for (int i = 0; i < ktList.Length; i++)
ktList[i] = new KTEntry();
}
