Pyjamarama: Routine at F3A7

F3A7: Routine at F3A7

Used by the routines at Update_Room00 and Invaders_Loop.

Input

Output

Inv_Update

F3A7

LD HL,(Inv_DataPtr)

Start of data.

Inv_Update_0

F3AA

LD A,(HL)

Get x pos.

F3AB

CP $FE

See if valid.

F3AD

JR NZ,Inv_Update_1

F3AF

INC HL

If not valid, move onto next invader.

F3B0

INC HL

F3B1

JR Inv_Update_0

Inv_Update_1

F3B3

CP $FF

Check for end of data.

F3B5

JR NZ,Inv_Update_3

If not the go on to handle invader.

F3B7

LD HL,Invaders_Data

Reset start of first invader.

F3BA

LD (Inv_DataPtr),HL

F3BD

LD HL,(Inv_StartFrame)

F3C0

LD A,(Inv_NextFrame)

Update frame to the next one.

F3C3

LD (Inv_CurrentFrame),A

F3C6

INC A

Update to next frame.

F3C7

CP H

See if frame has reached end frame.

F3C8

JR NZ,Inv_Update_2

F3CA

LD A,L

Reset to start if so.

Inv_Update_2

F3CB

LD (Inv_NextFrame),A

Store updated frame.

F3CE

LD A,(Invaders_ChangeDirFlag)

F3D1

ADD A,A

F3D2

LD (Inv___Flag),A

F3D5

OR A

F3D6

RET Z

F3D7

XOR A

Reset flag.

F3D8

LD (Invaders_ChangeDirFlag),A

F3DB

LD A,(Invaders_CurrentDir)

Change direction.

F3DE

NEG

F3E0

LD (Invaders_CurrentDir),A

F3E3

RET

Inv_Update_3

F3E4

LD C,A

X position.

F3E5

INC HL

F3E6

LD B,(HL)

Y position.

F3E7

INC HL

F3E8

LD (Inv_DataPtr),HL

Set pointer to next invader.

F3EB

DEC HL

Push address back to current invader.

F3EC

DEC HL

F3ED

LD (BitmapX),BC

Set draw to position.

F3F1

LD A,(Invaders_CurrentDir)

Get direction and update X position in direction.

F3F4

ADD A,C

F3F5

LD C,A

F3F6

LD (HL),A

F3F7

CP $E8

Check for right hand end of screen reached.

F3F9

JR NZ,Inv_Update_5

Inv_Update_4

F3FB

LD A,$01

If reached, change direction for all invaders.

F3FD

LD (Invaders_ChangeDirFlag),A

F400

JR Inv_Update_6

Inv_Update_5

F402

CP $08

Check for left hand end of screen reached.

F404

JR Z,Inv_Update_4

Change direction if so.

Inv_Update_6

F406

LD A,(Inv___Flag)

F409

ADD A,B

F40A

LD B,A

F40B

CP $A0

F40D

JR C,Inv_Update_7

F40F

LD A,$01

F411

LD (DeathFlag),A

Draw invader

Inv_Update_7

F414

INC HL

Store any change in the Y position.

F415

LD (HL),B

F416

LD A,(Inv_CurrentFrame)

Erase invader with previous frame.

F419

CALL Bitmap16Draw

F41C

LD (BitmapX),BC

Draw invader at new position and new frame.

F420

LD A,(Inv_NextFrame)

F423

CALL Bitmap16Draw

F426

LD HL,(BitmapX)

Get draw position again and check for hitting Wally.

F429

LD B,$02

F42B

CALL Wally_HitTest

F42E

LD HL,(BitmapX)

Get position again.

F431

LD A,R

Create a random number.

F433

CP $08

If great or equal to 8 then end.

F435

RET NC

Drop a bomb.

F436

EX DE,HL

F437

LD B,$03

number of bombs.

F439

LD HL,Arcade_BombData

Start of bomb data.

Bombs, look for an empty slot.

Inv_Update_8

F43C

LD A,(HL)

Get x position.

F43D

CP $FF

See if bomb is active.

F43F

JR Z,Inv_Update_9

If not, create one.

F441

INC HL

If so, move onto next bomb.

F442

INC HL

F443

INC HL

F444

DJNZ Inv_Update_8

F446

RET

Bomb, empty slot found.

Inv_Update_9

F447

LD (HL),E

Store position.

F448

INC HL

F449

LD (HL),D

F44A

INC HL

F44B

EX DE,HL

F44C

LD HL,$F45D

Get the next bitmap within the range of ($c0 ~ $c6)

F44F

INC (HL)

F450

LD A,(HL)

F451

CP $C7

F453

JR NZ,Inv_Update_10

F455

LD A,$C0

F457

LD (HL),A

Inv_Update_10

F458

LD (DE),A

Store the frame for this bomb.

F459

CALL Bitmap16Draw

Draw bomb.

F45C

RET