I disassembled the Subroc Supergame

[Captain Cozmos]

Rather, I should title this "I am currently disassembling the Subroc Supergame"  As this is a work in progress.

 

I will display snippets here and there to show progress but overall I will eventually post the entire thing.

The goal is to have a complete disassembly with a make file that will assemble the whole game into a disk or datapack
Another goal will be to have enough information and labels that you can at least tell which parts are what.

Whether there will be enough info that you can alter the game enough to add or subtract elements remains to be seen.

So far I have disassembled the Boot Block and the Title screen.  The patterns, Sound Table, NMI, Zero Page routines, loader for the game itself.

The loader starts off by loading block 3 to $CC00, passes the CURRENT_DEV (device id) then jumps to $CF37 to display the title screen and animation while simultaneously loading the main portion of the game into memory.


This is a small snippet for setting up the TITLE Screen

SETUP_TITLE_SCREEN:
    LD      HL, 0
    LD      BC, 3FFFH
    XOR     A
    CALL    SUB_CFD2
    CALL    SETUP_VRAM
    LD      HL, 20H
    LD      BC, 5AH
    LD      DE, 100H
    CALL    PUT_ASCII
    LD      HL, TITLE_PATS_02
    LD      BC, 100H
    LD      DE, 0
    CALL    SUB_CFB2
    LD      HL, TITLE_PATS_03
    LD      BC, 1A8H
    LD      DE, 2D8H
    CALL    SUB_CFB2
    LD      HL, DRIP_PATTERN
    LD      BC, 20H
    LD      DE, 2B00H
    CALL    SUB_CFB2
    LD      HL, TITLE_PATS_01
    LD      DE, 1880H
    LD      BC, 281H
    CALL    SUB_CFB2
RET

As I identify and label more a clearer picture will form.

Edited October 18, 2023 by Captain Cozmos

[Captain Cozmos]

Patterns and Name Table loaded into Tony Cruise's tile editor from direct data.

 

 

 

 

 

Personally, I like Color in my projects

 

 

 

Edited October 18, 2023 by Captain Cozmos

[Captain Cozmos]

Lastly for this morning.  The routine that actually sets up the main Title Screen before it starts dripping..

DISPLAY_TITLES:
    LD      bc, 704h                                   ; background color to 4
    LD      ix, WRITE_REGISTER
    CALL    sub_CECC
    LD      bc, 1A2h                                   ; register 1, 16k, interrupt enabled, mode 1, 16x16 sprites (in another thread I called this mode 0, it is mode 1)
    LD      ix, WRITE_REGISTER
    CALL    sub_CECC
    LD      hl, TITLE_PATTERNS
    LD      bc, 480h
    LD      de, 300h
    CALL    LOAD_TO_VRAM
    LD      hl, TITLES_COLOR_TABLE
    LD      bc, 12h
    LD      de, 2B0Ch
    CALL    LOAD_TO_VRAM
    XOR     a
    LD      bc, 300h
    LD      hl, 1800h
    CALL    sub_CFD2
    LD      hl, NAME_TABLE
    LD      bc, 140h
    LD      de, 1840h
    CALL    LOAD_TO_VRAM
    LD      de, THE_OFFICIAL_TXT
    LD      hl, 1823h
    CALL    sub_D04B
    LD      de, COLECO_1984_TXT
    LD      hl, 1A41h
    CALL    sub_D04B
    LD      de, SEGA_1982_TXT
    LD      hl, 1A61h
    CALL    sub_D04B
    LD      de, SR_AND_SEGA_ARE_TXT
    LD      hl, 1A83h
    CALL    sub_D04B
    LD      de, TRADEMARKS_OF_TXT
    LD      hl, 1AA3h
    CALL    sub_D04B
    LD      de, SEGA_ENTERPRISES_TXT
    LD      hl, 1AC3h
    CALL    sub_D04B
    LD      hl, DRIP_PARTS
    LD      bc, 2C0h
    LD      de, 3800h
    CALL    LOAD_TO_VRAM
    LD      hl, DRIP_ANIMATION_PARTS
    LD      bc, 30h
    LD      de, 0CE48h
    LDir
    LD      bc, 1E2h
    LD      ix, WRITE_REGISTER
    CALL    sub_CECC

Edited October 18, 2023 by Captain Cozmos

[Captain Cozmos]

Mulling through the code and now I have a bit more insight on how Super Games work.

Originally, I learned from the Mayan super game source on how to load blocks into memory.
The example it gives is to:

 

READ1BLOCK

do something in between

READ1BLOCK

do something in between

What I found out is that in Subroc, this method is only used once to move the loader program above $8000.
Once the routine is in high memory and executing, it can safely bank switch Smart Writer out and load the program anywhere it wants that is not being used.
What it also does is:

START_RD_1_BLOCK

play some music, animation, whatever

END_RD_1_BLOCK once the block has been loaded

This way it multitasks without the stutter.

I suspect with START_RD_1_BLOCK it tells the 6801 to go fetch the data and the Z80 does not wait for it to reply or finish before doing something new.
And if you use READ1BLOCK, the system has to wait till it is done reading before moving on.

I came across this in Diablo.
The examples I have come across in all the fan based books have used READ_KEYBOARD

 

While Diablo uses START_RD_KBD and END_RD_KBD to multitask through the game.


As I progress through the disassembly, some or all of this info may change but this is what I have learned thus far.

 

EDIT:

On a side note, this game also does not use the OS7 Colecovision BIOS.
It sets up all the RST vectors in page 0 then uses the ADAM EOS for everything else.

Edited October 18, 2023 by Captain Cozmos

[Captain Cozmos]

Corrections already when I should have gone to bed after being up all night.

The Boot code I initially said sets up the system was partially correct.
First: ADAM internal program loads the first block (1k), starting at 0, to $C800 then executes it.

That was my initial BOOT BLOCK.

 

The Boot Block then loads the TITLES program into CC00 then jumps to $CF37 to do setup, run the animation, music and load in the main game.
 

I misread a portion of the code which

register's HL $CC00 is the destination in memory

register's DE $1 is the starting block on the media

register B $3 is a counter.

 

This is strait forward but I was going off the Mayan Source way of the boot block.

This BOOT BLOCK loads 4 blocks (4k), starting at block 1 ($400), into $CC00 which is right after the $C800 default ADAM boot area for disks and data packs while $8000 is for cartridges.

 

All of that will be updated in the disassembly when completed.

I hope this clears up any confusion.

Edited October 18, 2023 by Captain Cozmos

[Captain Cozmos]

Games is disassembled.
 

Here is a preliminary Map of what I have deciphered so far:

 

                          Memory Map of Subroc Super Game

 

Section       Size   Where in Media     Where in Ram when loaded

Boot            1k     ($000)                  $C800
Titles Main   2k     ($0400-$0FFF)       $CC00 Loaded in from Boot Block
Titles Data   2k     ($1000-$1BF0)      $C000  Overwrites Boot Block after Title executes
Game Main  36k    ($1C00-$ABFF)      $2000  Loaded in from Titles Program

High Score   1k     ($AC00)                $B000  Loaded into Ram along with the main program

 
When Game is over (Hall of Fame)

High Score     2k   ($AC00-AFFF)          $1C00 When Game is over.
HScore Edit  10K   ($14800-$173F0)    $9800  Loaded in from Main program when game is over.
HS Edit Data  2k   ($B800-$BFF0)        $C000

 

I have found that the Hall of Fame design takes over most of the memory once the game is over forcing ADAM to reload most of, if not all of it from the beginning in order to play again.

This may change as I do more work.
 

All sections have been disassembled and now the data and pointers  to be identified and labelled.
 

I have found a lot of data on both disk and ddp that do not belong to the Sub Roc and may just be what was on the media prior to it's creation.

After the whole thing is disassembled and rebuilt we will have the cleanest version since it's creation.

 

03 Cosmos

Edited October 18, 2023 by Captain Cozmos