Krakout: Resolve both balls' bounces for the frame

A75E: Resolve both balls' bounces for the frame

Resolves ball A's bounce, then ball B's while it is in play. Falls through into the bat bounce for ball B.
resolve_ball_bounces	A75E	XOR A	Select ball A in the which-ball selector.
	A75F	LD (resolve_ball_sel),A	Select ball A in the which-ball selector.
	A762	LD IY,ball_a_x_accum	Point IY at ball A's state.
	A766	CALL ball_bounce	Point IY at ball A's state.
	A769	LD A,(ball_b_in_play)	Stop here unless ball B is in play.
	A76C	OR A
	A76D	RET Z
	A76E	LD A,$01	Select ball B in the which-ball selector.
	A770	LD (resolve_ball_sel),A	Select ball B in the which-ball selector.
	A773	LD IY,ball_b_x_accum	Point IY at ball B's state, then fall through into the bat bounce for ball B.

Routines