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Toejam and Earl

ROM File: Toejam & Earl (REV 00) (U) [!].bin

The disassembled source code to Toejam and Earl on the Sega Megadrive, my favourite game on my favourite console.

Warning! - I'm currently working on this game so some info will not be entirely accurate however it is constantly being refined.

Current State (Last updated - 11 Apr 2019)

I finally have a complete copy of the disassembled Toejam and Earl source code that can be reassembled into a bit perfect copy of the original ROM file! I am truely over the moon to have reached such an important and game-changing milestone!

The code is not yet at a point where I am happy to release it to the general public, it is messy, fragmented and there are a lot of areas that I want to clean up and document first. Rest assured however, I will eventually make the GitHub repo it is stored in open to all!

Unitl then, please enjoy these few snippets of the disassembled source code that I find (and think you will find) particularly interesting. If you are interested in reading more about the disassembling process itself head over to my dedicated topic on Romhacking.net.

A quick summary of my current priorities breaks down as follows (in roughly this order):

  • Presents related data (how do Rocket Skates work, what sets how long tomatoes last, etc).
  • Random map generation routine.
  • Enemy related data (A.I., sprites, attributes like health, speed, damage, etc)
  • Player (Toejam and Earl) related data (Health, speed, sprites, etc)
  • Everything else...

If there is anything you have a particular interest in let me know either on the comments here or on the RHDN topic and I'll see what I can find.

ROM (1MB, approx 4.62% deciphered):
Key: Game Dynamics Data Block Graphics General Routine Error Handling ROM Header Empty Space
+/- Offset Length (hex) Opcode / Hexcode Instruction / ASCII Description
+
00000-001FF
200
00FF 8000 0000 ...
.ÿ€.....
Standard rom header with the following details:
    Initial stack pointer value: 00FF 8000
    Entry Point: 0000 0202
    ROM Details: SEGA GENESIS    (C)SEGA 1991.JULTOEJAM & EARL TOEJAM & EARL GM MK-1020 -00
+
00200-00201
2
60FE
BRA       $00000200
1 line infinite loop, used for exceptions.
+
00202-0028F
8E
4AB9 00A10008 ...
TST.L     $00A10008 ...
Megadrive initialisation routine...
+
00290-002FB
6C
8000 3FFF 0100 ...
N/A
Setup values
+
002FC-00305
A
4A79 00C00004 ...
TST.W     $00C00004 ...
Game Entry Point.
+
00306-00321
1C
4E71 ...
NOP ...
Clear RAM Routine.
+
0BB78-0BC27
AB
207C 00FFA248 ...
MOVE.L    #$00FFA248,A0 ...
Sets Toejam and Earl's Starting Stats...
+
2C52C-2E72B
21FF
N/A
N/A
Graphics
+
FFDE7-FFFFF
219
FFFF FFFF FFFF ...
N/A
Empty space

RAM (64KB, approx 1.00% deciphered):
Key: Game Dynamics General Routine Unused
Offset GENS Savestate Offset Length (hex) Original Value Useful Values Description
A248 C6C0 1 03 00-09 Toejam's lives.
A249 C6C1 1 03 00-09 Earl's lives.
A24A C6C2 1 Unknown 00-?? Toejam's cash.
A24B C6C3 1 Unknown 00-?? Earl's cash.
A24C-A24D C6C4-C6C5 2 0000 0000-???? Toejam's score.
A24E-A24F C6C6-C6C7 2 0000 0000-???? Earl's score.
A250 C6C8 1 00 00-09 Toejam's promotion level. (See note 1)
A251 C6C9 1 00 00-09 Earl's promotion level. (See note 1)
A298-A29B C710-C713 4 Unknown ??-?? Toejam's health.
A29C-A29F C714-C717 4 Unknown ??-?? Earl's health.
DA8A-DAC1 FF02-FF39 37 00 00-01 Stores whether presents are identified or not. (See note 3)
DAC2-DAE1 FF3A-FF59 1F 1B or FF 00-1B Stores Toejam and Earl's inventory. (See note 2)
DAE2-DAF1 FF5A-FF69 10 Mixed Unknown Present 1 data.

ADDITIONAL INFO:
Offset GENS Savestate Offset Length (hex) Original Value Useful Values Description
CRAM Maybe? (TBC) A622-A9FD 3DD Mixed Unknown Contains the level layout of the current level.
CRAM Maybe? (TBC) A9FE-ADD9 3DC Mixed Unknown Contains the level layout of level 1.
CRAM Maybe? (TBC) ADDA-B1B5 3DD Mixed Unknown Contains the level layout of level 2 while your on level 3.
CRAM Maybe? (TBC) B800-C6BF EBF Mixed Unknown Moving letter graphics.

Notes:

Note 1:

00 = Wiener 05 = Bro
01 = Dufus 06 = Homey
02 = Poindexter 07 = Rapmaster
03 = Peanut 08 = Funk Lord
04 = Dude 09 = Goner

Note 2:

00 = Icarus Wings 0A = Rootbeer 14= Extra Buck
01 = Spring Shoes 0B = Promotion 15 = Jackpot
02 = Innertube 0C = Un-fall (Togetherness in 2 player) 16 = Tomato Rain
03 = Tomatoes 0D = Rain Cloud 17 = Earthling
04 = Sling Shot 0E = Fudge Sundae 18 = School Book
05 = Rocket Skates 0F = Decoy 19 = BoomBox
06 = Rose Bushes 10 = Total Bummer 1A = Random
07 = Super Hitops 11 = Extra Life 1B = Bonus Hi Tops
08 = Doorway 12 = Randomizer FF = Empty
09 = Food 13 = Telephone  

Note 3:

These come it pairs with the value in the even offsets representing the present and the value in the following odd offset representing if it is identified or not. 00 means it's not, 01 means it is.

History

Back in October 2015 I was contacted by a fellow Toejam and Earl fan going by the name of Juan Perez. Juan had created what he believed to be a disassembly of Toejam and Earl by running the original ROM file through a program called Disasm.exe (which I beleive is part of Sega-asm.zip). The disassembly, having been ran over the entire ROM file, was pretty messy containing a lot of nonsense code as a result of disassembling data (images, music, sound effects, etc) as if it were code, however, it was enough to peak my interest as a fun, interesting, long-term project.

Since then I've been working to turn this disassembly into a fully assemblable, editable and commented source code.

Credits and Thanks

The following people and pages have been of great help during the completion of this project. Huge thanks to them and their respective authors (listed in order of discovery):

Screenshots

Nothing to see here at the moment.

Want To Know More?

If you want to know more about this project you can email me using the details in the contact page or drop by my dedicated topic on Romhacking.net.

Downloads

T.E.S.S.E. Toejam and Earl SaveState Editor created by me in VisualBasic.Net back when I was first learning about ROM hacking. Easy to use, lets you edit inventory and stats using simple menus. Works on GENS savestates. Screenshot of T.E.S.S.E