for (int idx = 0; idx < 10; idx++)
for (Square s1 = SQ_A1; s1 <= SQ_D4; ++s1)
if (MapA1D1D4[s1] == idx && (idx || s1 == SQ_B1)) // SQ_B1 is mapped to 0
+ {
for (Square s2 = SQ_A1; s2 <= SQ_H8; ++s2)
if ((StepAttacksBB[KING][s1] | s1) & s2)
continue; // Illegal position
else
MapKK[idx][s2] = code++;
+ }
// Legal positions with both kings on diagonal are encoded as last ones
for (auto p : bothOnDiagonal)