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 of the info will not be entirely accurate however and is constantly being refined.
Current State (Last updated - 16 Jul 2018)
It has become apparent that storing the entire source code to the game on this single web page is an unrealistic plan! And even if it was realistic it certainly isn't the optimal way to store or share it. So instead this page just contains a few snippets of the disassembled source code that I find (and think you will find) particularly interesting along with a brief summary of my current goals and priorities.
Eventually, when I'm at a point that I am happy to release the source, a GitHub repository or similar will be set up to hold it and the details for it will appear here.
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):| +/- | 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. |
| + |
00322-0BB77 |
B856 |
8000 ... |
OR.L #$120000C0,-(A1) ... |
Unknown |
| + |
0BB78-0BC27 |
AB |
207C 00FFA248 ... |
MOVE.L #$00FFA248,A0 ... |
Sets Toejam and Earl's Starting Stats... |
| + |
0BC28-2C52B |
20901 |
4A28 0001 ... |
TST.B $0001(A0) ... |
Unknown |
| + |
2C52C-2E72B |
21FF |
N/A |
N/A |
Image data |
| + |
2E72C-FFDE6 |
D16BB |
0000 0000 ... |
OR.B #$00,D0 ... |
Unknown |
| + |
FFDE7-FFFFF |
219 |
FFFF FFFF FFFF ... |
N/A |
Empty space |
RAM (64KB, approx 1.00% deciphered):
| Offset | GENS Savestate Offset | Length (hex) | Original Value | Useful Values | Description |
| 0000-A247 | 2478-C6BF | A248 | Mixed | Unknown | Unknown |
| A248 | C6C0 | 1 | 03 | 00-09 | Changes the amount of Toejam's lives. |
| A249 | C6C1 | 1 | 03 | 00-09 | Changes the amount of Earl's lives. |
| A24A | C6C2 | 1 | Unknown | 00-?? | Changes the amount of Toejam's cash. |
| A24B | C6C3 | 1 | Unknown | 00-?? | Changes the amount of Earl's cash. |
| A24C-A24D | C6C4-C6C5 | 2 | 0000 | 0000-???? | Changes Toejam's score. |
| A24E-A24F | C6C6-C6C7 | 2 | 0000 | 0000-???? | Changes Earl's score. |
| A250 | C6C8 | 1 | 00 | 00-09 | Changes Toejam's level. (See note 1) |
| A251 | C6C9 | 1 | 00 | 00-09 | Changes Earl's level. (See note 1) |
| A252-A297 | C6CA-C70F | 46 | Mixed | Unknown | Unknown |
| A298-A29B | C710-C713 | 4 | Unknown | ??-?? | Toejam's health. |
| A29C-A29F | C714-C717 | 4 | Unknown | ??-?? | Earl's health. |
| A2A0-DA89 | C718-FF01 | 37EA | Mixed | Unknown | Unknown |
| 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. |
| DAF2-FFFF | FF6A-123E2 | 250D | Mixed | Unknown | Unknown |
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):
- Marc at DarkDust.net - Great info on ROM headers and initialising the Sega Megadrive.
- Big Evil Corporation - Very accessible info on ROM headers, initialising and programming the Sega Megadrive.
- MarkeyJester’s Motorola 68K Tutorial - Really good guide to the 68K processor.
- Hivebrain's Sonic 1 Disassembly at SonicRetro - A clear and well commented disassembly of Sonic 1.
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. |
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