Gyruss: Routine at 86E9

86E9: Handle sprite types $12 - $13

Used by the routine at handle_sprite_type_14.

Input
A	Sprite type
IX	Sprite data

handle_sprite_types_12_13

86E9

CP $12

Is sprite type < $012

86EB

JR C,handle_sprite_type_03

If so, jump ahead

86ED

CP $14

Is sprite type >= $014

86EF

JR NC,handle_sprite_type_03

If so, jump ahead

Sprite types $12 - $13 (enemy missile)

86F1

LD A,(frame_counter)

Frame counter

86F4

LD B,A

Store in B

86F5

AND $01

Every 2nd frame

86F7

RET NZ

Return to return_from_sprite_handler

86F8

LD A,B

Frame counter

86F9

AND $0F

Mod 16

86FB

JR NZ,handle_sprite_types_12_13_0

If not zero then skip animation

86FD

LD A,(IX+$00)

Get sprite type

8700

XOR $01

Flip bit 0 to change between $12 and $13

8702

LD (IX+$00),A

Save new type

handle_sprite_types_12_13_0

8705

INC (IX+$05)

Mark for pattern reload

8708

DEC (IX+$01)

Decrement polar y

870B

RET

Return to return_from_sprite_handler