Alien (BUGFIX 1.7): Routine at 39830

Entry point called from UpdateAlienAnim with B=2: the first BlitJonesFrame pass XOR-erases the cat at its old position, then (via the DJNZ at its end) AdvanceJonesPos moves it 4 pixels right and a second pass redraws it — the classic XOR erase / advance / redraw cycle.

Entry point called from UpdateAlienAnim with B=2: the first BlitJonesFrame pass XOR-erases the cat at its old position, then (via the DJNZ at its end) AdvanceJonesPos moves it 4 pixels right and a second pass redraws it — the classic XOR erase / advance / redraw cycle.
39830	LD B,2	B=2: advance position then blit