The Point&Click adventure game genre started on Maniac Mansion for the C64 and spread easily over other 8 bit computers based on the 68XX processor family. Then the game and the genre jumped to the 16 bits without even touching one Z80 computer.

Mouse control wasn't planed on the 1987 release, after all that was the precise time when the device was being introduced. But also because in the C64 memory didn't remain space to put the needed mouse driver.  

Later in 2009, a C64 enthusiast nicked enthusi made an attempt to put mouse control on the C64 game.

But the best is: to do it he reverse engineered completely the game. First he removed the special disc format, and then he carefully placed all the found data on a NeoRam-GeoRam cartridge image. He explains the process on his release instructions. A pity he didn't free the code obtained.

The special game image can be downloaded from here. I have installed the ViceC64 emulator, as it supports the NeoRam-GeoRam cartridge emulation, and it works flawlessly. Once the image is loaded it must be launched with  SYS 57000 or SYS 57E3. He has added mouse control, some extras and has fixed the flagrant errors found, but the game works exactly the same.

As you already know, this game is based on a script language and parser named SCUMM, this first time version 0. The subsequent versions up to 2 where made for the other computers conversions, removing the "C64 only" characteristics on Maniac Mansion(like SID music, side scroll, hardware sprites or graphic modes) to make SCUMM more portable. Later on, new games added more and more characteristics to SCUMM, up to version 8.

The NeoRam-GeoRam cartridge is a Ram expansion, but the NeoRam version has a battery to maintain the memory content. It works paginating 16Kb segments like the Enterprise memory. I have peeked the image with an Hex editor, and all the information is there completely accessible without protections. Probably even the SID songs can be easily extracted and converted.

The scripts seem to match the real content of the NeoRam image:

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Observe: 40h            cutscene()
             6001h         cursorCommand(kModeKeypad)
             0C01h         loadSound(1)
             5301h         lockSound(1)
             0C3Ah         loadSound(58)
             533Ah         lockSound(58)
             ..........etc.

The problem is that this is a huge work, the scripts seems to be very useful, but i think it is about 1 year work for 1 person.

Perfect! the kind of absurd and boring knowledge that I like...

It is not boring, and absurd, and I would like to see Maniac Mansion, and Zak Mckraken on EP even I played only 2-3 times with those games on C64, and I am happy if you start it

I want to create a new thread for this named "Mapping and disassembling C64's Maniac Mansion".

Done!

Ok, chapter one.

First of all I have to explain a little how the GeoRam-NeoRam cartridge works. It takes advantage of a little zone in the C64 memory map used for I/O with interface extensions, from DE00h to DFFFh. The cartridge implements a 256b window  on DE00h-DEFFh to read/write the extra memory. To select the visible 256b area two memory registers are provided, DFFFh to select the 16kb block and DFFEh to select the 256b page inside the 16kb block.

A typical cartridge has 512k of memory inside, but can grow up to 4M, i.e. DFFFh will contain from 0 to 31 or up to 255. On the other side DFFEh will hold 0 to 63, the number of possible 256b pages on a 16k block. Both registers are write-only, so the values have to be maintained on the program's variable zone.

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Launcher: just at block 0, page 0, there is a little launcher that copies a loader on main memory. The game can be started with SYS 57000, SYS 57E3 OR SYS DE00(I don't know why all the possibilities).

DE00   78         SEI ;disable interrupt
DE01   A2 1A      LDX #$1A ;load index register X inmediate with 1Ah

DE03   BD 00 DE   LDA $DE00,X        ;load A absolute indexed with X, (base address $DE00+X)
DE06   8D 00 08   STA $0800 ;store A absolute on ($0800)
DE09   E8         INX ;increment X
DE0A   F0 06      BEQ $DE12 ;branch if 0 so, copy from $DE1A to $DEFF
DE0C   EE 07 DE   INC $DE07 ;automodified code increments byte at $DE07
DE0F   4C 03 DE   JMP $DE03 ;loop ;jump to absolute address

DE12   A9 00      LDA #$00 ;ld A inmediate with $00
DE14   8D 07 DE   STA $DE07 ;automodified code restores a $00 byte at $DE07
DE17   4C 00 08   JMP $0800 ;jump to the copied code at $0800
This copies the following 230b chunk from the 256b window to 0800h in main memory and then jumps at it.

Loader:

0800   A9 00      LDA #$00 ;ld A inmediate with $00
0802   8D FF DF   STA $DFFF ;selects NeoRam 16k block 0
0805   8D FE DF   STA $DFFE ;selects NeoRam 256b page 0
0808   AD CE DE   LDA $DECE ; still unknown
080B   85 02      STA $02 ;this address is left unused on stock configuration
080D   AD 11 D0   LDA $D011 ;Screen control register #1
0810   29 EF      AND #$EF ;11101111b  Bit #4: 0 = Screen off
0812   8D 11 D0   STA $D011 ;Screen control register #1
0815   AD 91 08   LDA $0891 ;middle byte address of NeoRam ?
0818   8D 93 08   STA $0893 ;store intermediary value
081B   29 3F      AND #$3F ;00111111b    0 to 63 256b pages
081D   8D FE DF   STA $DFFE ;selects NeoRam 256b page
0820   AD 92 08   LDA $0892 ;high byte address of NeoRam ?
0823   0E 93 08   ASL $0893 ;\
0826   2A         ROL A ; \ take two higher bits of the intermediary byte and
0827   0E 93 08   ASL $0893 ; / put them on the two lower bits of the accumulator
082A   2A         ROL A ;/  
082B   8D FF DF   STA $DFFF ;selects NeoRam 16k block
082E   A2 00      LDX #$00

0830   BD 00 DE   LDA $DE00,X        ;\ transfer 256bytes chunks always from the $DE00-$DEFF
0833   9D 00 10   STA $1000,X        ; \ cartridge window, to $1000-$3FFF the code starts
0836   E8         INX ; /   at  $60C00-$63BFF on the cartridge memory always 16kb
0837   D0 F7      BNE $0830 ;/ block 18h, 24d, and 256b pages from 0Ch-3Bh, 12d-59d

0839   EE 35 08   INC $0835 ; this increases 256b the destination pointer
083C   EE 91 08   INC $0891 ; this increases the page on the cartridge pointer
083F   D0 03      BNE $0844 ; end of pages on the 16kb block
0841   EE 92 08   INC $0892 ;next 16kb block

0844   AD 35 08   LDA $0835 ;
0847   C9 40      CMP #$40 ;check if end of count
0849   D0 B5      BNE $0800 ;loop

084B   4C 00 10   JMP $1000 ;start the game

084E to 088D:
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

088E   4C 00 DE   JMP $DE00
0891   0C        
0892   06
0893   00

0894 to 08B2:
65 6E 74 68 75 73 69 20 6F 66 20 6F 6E 73 6C 61
75 67 68 74 20 20 20 6F 70 74 69 6F 6E 73 3A
"enthusi of onslaught   options:"
08B3   7C
08B4   00        
08B5   00        
08B6   7C        
08B7 to 08E5:
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Basically what it does is to load a contiguous zone from the cartridge to main memory at 1000h. This is very good news, because then I can take directly the chunk from the cartridge image and disassembly it externally of WinVice, the emulator and de-bugger I am using.

Being little chunks I have used an online disassembler: masswerk.

But from now on I will need one installed. Thanks for the advice.

I have found a disassembly of the Maniac Mansion script here. It is not the code of the program, much better, the rules that govern its behaviour.

It even has several maps of the game:

I know this topic is very old, but I have also wanted to see an Enterprise version of Maniac Mansion for about three decades!
gflorez, are you still on this project?

Rather than disassembling, an approach that suits me better is to use the ScummVM source as "documentation".
Based on that, and after a long time, what I've managed to do is create a viewer program for the background graphics of every room.
Not particularly fast (z88dk C implementation), but someone with better skills might be able to improve on that, and at least it proves that maybe it's not an impossible mission after all.
It uses the same data as the one on the C64 floppy disks; conversion of the graphics is done in run time.

Please try it out if you'd like. (I've attached a floppy disk image, because I'm using random access in the data files (EXOS 10), which is apparently not supported by EPFILEIO. Sorry about that.)