if (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1))
{
Square d = pawn_push(Us) + (square_file(s) == FILE_A ? DELTA_E : DELTA_W);
if (s == relative_square(Us, SQ_A1) || s == relative_square(Us, SQ_H1))
{
Square d = pawn_push(Us) + (square_file(s) == FILE_A ? DELTA_E : DELTA_W);