Krakout: Spawn objects from the current level's wave script

C61D: Spawn objects from the current level's wave script

Spawns at most one object per frame from one slot of the current level's wave script. That object is the ball gem as the secondary object, or an inhabitant in a free inhabitant record.
process_wave_script	C61D	LD A,(move_freeze)	Spawn nothing while the global move-freeze holds.
	C620	OR A
	C621	RET NZ
	C622	LD A,(death_pause_timer)	Spawn nothing while the death pause runs.
	C625	OR A
	C626	RET NZ
	C627	LD A,(level)	Index this level's wave script, 8 bytes per level.
	C62A	LD L,A
	C62B	LD H,$00
	C62D	ADD HL,HL
	C62E	ADD HL,HL
	C62F	ADD HL,HL
	C630	LD DE,wave_scripts
	C633	ADD HL,DE
	C634	CALL next_random	Draw a random byte; a value 0–7 (a 1-in-2 chance) selects the script slot, otherwise bail this frame.
	C637	AND $0F
	C639	CP $08
	C63B	RET NC
	C63C	LD D,$00
	C63E	LD E,A
	C63F	ADD HL,DE	Read the selected slot's value (the type to spawn).
	C640	LD A,(HL)
	C641	OR A
	C642	RET Z	Empty slot – spawn nothing.
	C643	PUSH AF	Empty slot – spawn nothing.
	C644	CP $11	The comet is the one type that skips the throttle.
	C646	JR Z,process_wave_script_1	The comet is the one type that skips the throttle.
	C648	LD HL,spawn_throttle	Throttle normal spawns: bump the spawn throttle, and spawn only when it reaches its limit. Short of that, return without a spawn.
	C64B	INC (HL)
	C64C	LD A,(HL)
	C64D	CP $32
	C64F	JR Z,process_wave_script_0
	C651	POP AF
	C652	RET
process_wave_script_0	C653	XOR A	On the fiftieth, reset the counter and let the spawn through.
	C654	LD (HL),A
process_wave_script_1	C655	POP AF	Recover the slot value the throttle test pushed aside.
	C656	CP $01	Dispatch on the slot value: the lowest spawns the ball gem, and anything else spawns a generic inhabitant.
	C658	JP NZ,process_wave_script_2
The ball-gem entry spawns the ball gem as the secondary object. It refuses while any ball or gem state that would conflict is active: ball_gem_frame, prize_on_field_latched, ball_b_in_play, double_bat_active, missile_active, missile_shot, fx_bomb_arm, fx_spawn_ball_arm, fx_despawn_arm.
	C65B	LD A,(ball_gem_frame)	Abort the spawn if any ball or gem state flag that would conflict is set.
	C65E	OR A
	C65F	RET NZ
	C660	LD A,(prize_on_field_latched)
	C663	OR A
	C664	RET NZ
	C665	LD A,(ball_b_in_play)
	C668	OR A
	C669	RET NZ
	C66A	LD A,(double_bat_active)
	C66D	OR A
	C66E	RET NZ
	C66F	LD A,(missile_active)
	C672	OR A
	C673	RET NZ
	C674	LD A,(missile_shot)
	C677	OR A
	C678	RET NZ
	C679	LD A,(fx_bomb_arm)
	C67C	OR A
	C67D	RET NZ
	C67E	LD A,(fx_spawn_ball_arm)
	C681	OR A
	C682	RET NZ
	C683	LD A,(fx_despawn_arm)
	C686	OR A
	C687	RET NZ
	C688	LD A,$01	Mark the ball gem out and request a fixed-position spawn.
	C68A	LD (ball_gem_frame),A
	C68D	LD (spawn_fixed_pos),A
	C690	CALL calc_spawn_coords
	C693	LD IX,obj2_object	Write the computed position into the ball gem's sprite record.
	C697	LD A,(work_x)
	C69A	LD (IX+$00),A
	C69D	LD A,(work_y)
	C6A0	LD (IX+$01),A
	C6A3	LD IY,obj2_record
	C6A7	LD (IY+$00),$01	Initialize the ball gem's logic record: an up-right heading, speed 1, and a cleared travel counter, then return.
	C6AB	LD (IY+$01),$01
	C6AF	LD (IY+$09),$00
	C6B3	LD (IY+$0A),$00
	C6B7	RET
Generic spawn for any type other than the ball gem. Reject a duplicate singleton and claim a free inhabitant record. Choose the position mode by type, then fall through to the logic-record initialization.
process_wave_script_2	C6B8	LD B,A	Scan the five inhabitant records for one that already holds this type.
	C6B9	LD C,$03
	C6BB	LD IY,inhabitant_records
process_wave_script_3	C6BF	LD A,(IY+$08)
	C6C2	CP B
	C6C3	JR Z,process_wave_script_4
	C6C5	LD DE,$0010
	C6C8	ADD IY,DE
	C6CA	INC C
	C6CB	LD A,C
	C6CC	CP $08
	C6CE	JR NZ,process_wave_script_3
	C6D0	JR process_wave_script_5
process_wave_script_4	C6D2	LD A,(IY+$0D)	Matched: if that instance is a singleton refuse to spawn a second.
	C6D5	OR A
	C6D6	RET NZ
process_wave_script_5	C6D7	LD C,$03	Find a free inhabitant record – one whose type is 0; none free means abort.
	C6D9	LD IY,inhabitant_records
process_wave_script_6	C6DD	LD A,(IY+$08)
	C6E0	OR A
	C6E1	JR Z,process_wave_script_7
	C6E3	LD DE,$0010
	C6E6	ADD IY,DE
	C6E8	INC C
	C6E9	LD A,C
	C6EA	CP $08
	C6EC	JR NZ,process_wave_script_6
	C6EE	RET
process_wave_script_7	C6EF	LD A,B	The orb only: skip the spawn while the capture slide runs.
	C6F0	CP $09
	C6F2	JR NZ,process_wave_script_8
	C6F4	LD A,(capture_slide)
	C6F7	OR A
	C6F8	RET NZ
process_wave_script_8	C6F9	LD A,B	Claim the free record: store the type into it.
	C6FA	LD (IY+$08),A	Claim the free record: store the type into it.
	C6FD	CP $0D	The wheel also arms the wheel swarm trigger.
	C6FF	JR NZ,process_wave_script_9
	C701	LD A,$01
	C703	LD (wheel_swarm_trigger),A
process_wave_script_9	C706	LD A,(IY+$08)	Types 6, 9 and $0D spawn at the fixed table entry 0; all others at a random entry.
	C709	CP $06
	C70B	JR Z,process_wave_script_10
	C70D	CP $09
	C70F	JR Z,process_wave_script_10
	C711	CP $0D
	C713	JR Z,process_wave_script_10
	C715	XOR A	Clear the fixed-position flag to request a random spawn position.
	C716	LD (spawn_fixed_pos),A
	C719	JR process_wave_script_11
process_wave_script_10	C71B	LD A,$01	Raise the fixed-position flag to request the fixed entry-0 spawn position.
	C71D	LD (spawn_fixed_pos),A
process_wave_script_11	C720	CALL calc_spawn_coords	Either way, pick the spawn cell.
	C723	PUSH BC	Point IX at this slot's sprite record, 9 bytes per slot.
	C724	LD B,C
	C725	LD DE,$0009
	C728	LD IX,object_table
process_wave_script_12	C72C	ADD IX,DE
	C72E	DJNZ process_wave_script_12
	C730	POP BC
	C731	LD A,(work_x)	Write the spawn position into the sprite record from the work X and work Y. Then fall through into the logic-record initialization.
	C734	LD (IX+$00),A
	C737	LD A,(work_y)
	C73A	LD (IX+$01),A

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