Atic Atac: Routine at 7EB2

Used by the routine at MAIN_LOOP.

MAIN_LOOP runs as fast as it can and calls this only when the ROM's frame counter has moved on, so what happens here is tied to the 50Hz interrupt rather than to how much there is to do.

It dispatches three records the main loop deliberately skips -- $EA90, $EA98 and $EAA0, the player, the weapon it has in flight, and the sound effect slot -- and then ticks the clock. That is why the player moves at a steady speed however crowded a room is, while the monsters are dispatched on every pass of the outer loop.

It runs with interrupts off, so a frame's work is never interrupted half way.

Used by the routine at MAIN_LOOP. MAIN_LOOP runs as fast as it can and calls this only when the ROM's frame counter has moved on, so what happens here is tied to the 50Hz interrupt rather than to how much there is to do. It dispatches three records the main loop deliberately skips -- $EA90, $EA98 and $EAA0, the player, the weapon it has in flight, and the sound effect slot -- and then ticks the clock. That is why the player moves at a steady speed however crowded a room is, while the monsters are dispatched on every pass of the outer loop. It runs with interrupts off, so a frame's work is never interrupted half way.
FRAME_TICK	7EB2	DI	Nothing may interrupt a frame's work.
	7EB3	PUSH IX
	7EB5	LD A,$01	A flag saying a frame is in progress.
	7EB7	LD ($5E04),A	A flag saying a frame is in progress.
	7EBA	LD IX,$EA90	The player, first of the three.
This entry point is used by the routine at FRAME_TICK_NEXT.
TICK_DISPATCH	7EBE	LD HL,FRAME_TICK_NEXT	Push the return address, then enter DISPATCH_ACTOR below its own PUSH HL -- it has already been done here.
	7EC1	PUSH HL
	7EC2	JP DISPATCH_PUSHED	Dispatch.