L15_Swap
static void L15_Swap(struct l15_state *l15,const LByteType pos1, const LByteType pos2);
L15_Swap(l15, i, (l15->stateIndex += (l15->L15_state[i] + (xx)))); \
L15_Swap(l15, l15->L15_state[l15->L15_x], l15->L15_y);