Toejam and Earl
ROM File: Toejam & Earl (REV 00) (U) [!].bin
The memory map of Toejam and Earl on the Sega Megadrive, my favourite game on my favourite console.
I'm currently working on this game so some of the info will not be entirely accurate however it is constantly being refined.
Juan Perez originally contacted me in October 2015 with a disassembly he created of Toejam and Earl using Disasm.exe (which I belive is part of Sega-asm.zip) using the arguments 'disasm -a -x' and since then, despite not yet hearing from him again, I've been working to decipher and annotate all the code it contains.
The disassembly was ran over the entire ROM file meaning it contains nonsense code as a result of disassembling data (images, music, sound effects, etc) as if it were code. Over time I will root these out and remove them.
This page is really just for storing the results of the process and all the data that is discovered. To read more about the actual 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 no. 00 means it's not, 01 means it is. |
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 repective 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.
| T.E.S.S.E. | Toejam and Earl SaveState Editor created by me in VisualBasic.Net. Easy to use, lets you edit inventory and stats using simple menus. Now works in single player! |
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