movegen.go

package main

const (
	MoveQuiet byte = iota
)

type Move struct {
	From    byte
	To      byte
	Kind    byte
	Promote byte
	Score   int16
}

func MoveGen(b *Board) []Move {
	retval := make([]Move, 0, 32)
	for i := A1; i <= H8; i++ {
		if !OnBoard(i) || GetPiece(b.Data[i]) == EMPTY {
			continue
		}
		
		if GetPiece(b.Data[i]) == PAWN {
			if b.ToMove == WHITE && !IsBlack(b.Data[i]) {
				/* Pawn push one square. */
				PawnPush := i + 10
				
				/* OnBoard test not needed, since pawns get promoted at rank 8
				 * and the pawn is not moving to the side. */
				if GetPiece(b.Data[PawnPush]) == EMPTY {
					retval = append(retval, Move{byte(i),
						byte(PawnPush), MoveQuiet, EMPTY, 0})
				}
				
				/* Captures are also side-dependent. */
			} else if b.ToMove == BLACK && IsBlack(b.Data[i]) {
				/* Pawn push one square. */
				PawnPush := i - 10
				
				/* OnBoard test not needed, since pawns get promoted at rank 8
				 * and the pawn is not moving to the side. */
				if GetPiece(b.Data[PawnPush]) == EMPTY {
					retval = append(retval, Move{byte(i),
						byte(PawnPush), MoveQuiet, EMPTY, 0})
				}
				
				/* Captures are also side-dependent. */
			}
		} else {
			/* ... */
		}
	}
	return retval
}

func MakeMove(b *Board, m *Move) {
	b.Data[m.To] = b.Data[m.From]
	b.Data[m.From] = EMPTY
	b.ToMove ^= BLACK
}