Values
| Offset |
Description |
Note
|
| 0x1430
|
Array which contains music numbers for each map (WORD ARRAY).
|
|
| 0x0ad2
|
Demo properties (structure array, 0xe bytes long).
|
- 0 (w), Level map number
- 2 (w), Level scroll page to start from (but the next scroll page won't be the next to this!)
- 4 (w), ???
- 6 (w), ???
- 8 (w), Player start X position + 128
- A (w), Player start Y position + 128
- C (w), ???
|
| 0x0dde
|
Level map world-level number (structure array, 0x4 bytes long).
|
- 0 (w), World number tile
- 2 (w), Level number tile
- To put a number just write <number> + 0x1A, zero extended
|
Functions
Title Screen functions
Button check
| Offset |
Description
|
| ROM:00000B18
|
title_screen_check_buttons CODE XREF: sub_84E+15C�p.
|
| ROM:00000B18
|
btst #5,(word_FF001C).l ; Check  button.
|
| ROM:00000B20
|
bne.w loc_B4C ; If it's pressed, branch.
|
| ROM:00000B24
|
btst #7,(word_FF001C).l ; Check  button.
|
| ROM:00000B2C
|
bne.w loc_B4C ; If it's pressed, branch.
|
| ROM:00000B30
|
btst #6,(word_FF001C).l ; Check  button.
|
| ROM:00000B38
|
bne.w loc_B4C ;If it's pressed, branch.
|
| ROM:00000B3C
|
btst #4,(word_FF001C).l ; Check  button.
|
| ROM:00000B44
|
bne.w loc_B4C ; If it's pressed, branch.
|
| ROM:00000B48
|
bra.w locret_B6A ; No button pressed, branch to this other one.
|
Level functions
Bonus Level
| Offset |
Instruction |
Comment
|
| ROM:0000780A
|
move.w d3,d0
|
| ROM:0000780C
|
mulu.w #$20,d0
|
| ROM:00007810
|
cmpi.w #0,4(a6,d0.w)
|
| ROM:00007816
|
bne.w loc_792A
|
| ROM:0000781A
|
cmpi.w #2,(word_FF0042).l
|
Compare 2 with current level map number
|
| ROM:00007822
|
beq.w loc_7836
|
If level map number is 2, branch
|
| ROM:00007826
|
cmpi.w #5,(word_FF0042).l
|
Compare 5 with current level map number
|
| ROM:0000782E
|
beq.w loc_7836
|
If level map number is 5, branch
|
| ROM:00007832
|
bra.w loc_7842
|
As you can clearly see, level map number 2 and 5 are respectively the Level 1-1 bonus, and the Level 1-2 bonus.
This makes the level not restart after exiting out of this level and returning to the main one, making it appear as a single level.
Adding another level to the list should be as simple as adding a cmp instruction and branching accordingly.
Sound Driver functions
The first two routines described below are easy to use subroutines which can be used respectively
to play a background music or a sound effect. They handle calling the sound driver for you.
The BGM one is used by loading a word containing a music number from 0x0000 to 0x00FF into
the address $ff6c00, and by jumping to it with a jump or branch to subroutine.
The SFX one works the same as the BGM one, but a sfx number is loaded into address $ff6c02.
The first line of the functions is their starting address.
Play BGM
| Offset |
Instruction |
Comment
|
| ROM:000EE76C
|
move.w d0,-(sp)
|
Save d0 onto stack
|
| ROM:000EE76E
|
move.w #0,d0
|
Move 0 into d0
|
| ROM:000EE772
|
move.b (word_FF6C00+1).l,d0
|
Move lower byte of word at ff6c00 into lower byte of d0
|
| ROM:000EE778
|
move.w d0,(word_FF6D00).l
|
Move d0 into address $ff6d00
|
| ROM:000EE77E
|
jsr sound_driver_play
|
Go to sub_F004C subroutine
|
| ROM:000EE784
|
move.w (sp)+,d0
|
Load d0 from stack
|
| ROM:000EE786
|
rts
|
Return (from this Subroutine)
|
Play SFX
| Offset |
Instruction |
Comment
|
| ROM:000EE788
|
move.w d0,-(sp)
|
Save d0 onto stack
|
| ROM:000EE78A
|
move.w #$8000,d0
|
Move $8000 into d0
|
| ROM:000EE78E
|
move.b (word_FF6C02+1).l,d0
|
Move lower byte of word at $ff6c02 into lower byte of d0
|
| ROM:000EE794
|
move.w d0,(word_FF6D00).l
|
Move d0 into word at address $ff6d00 (sound driver related)
|
| ROM:000EE79A
|
jsr sound_driver_play
|
Jump to (sound driver play?) subroutine
|
| ROM:000EE7A0
|
move.w (sp)+,d0
|
Load d0 from stack
|
| ROM:000EE7A2
|
rts
|
Return (from this Subroutine)
|
button.
button.
button.
button.