The Muppets On The Go!

The Muppets On The Go!
Developer: Climax Studios Publisher: Sega Platform: Sega Pico Released in US: March 1996 This game has hidden development-related text. This game has debugging material. This game has a hidden sound test. This game has a development article

To do: Full source code and art assets.

It's The Muppets, but on the go. Makes sense.

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Development Info

Interrupt Handler

A generic error handler for displaying an error message with a dump of register values, called by interrupt vectors.

To activate it, we can replace one of the function calls at startup to instead call one of the interrupt vectors, by applying patch 000002e0 = 08 7e.

Unfortunately, this isn't sufficient to get readable text, since the original bitmap font used for this screen was overwritten with code. However, we can copy a compatible font from another ROM (e.g. from Keyboard Pico: Kantan Waku Waku Keyboard) and write it on top of existing graphics data. Afterwards, we also need to update the data address referenced by the font loading function to instead use the address of the overwritten data.

Due to the size of the full patch, it's available as a script.

Error strings are located at 0xABE:

NOT A 'PAGE' FILE!!
NOT A 'RNCx' FILE!!
NOT A 'MSPR' FILE!!
BUS ERROR!!
ADDRESS ERROR!!
ILLEGAL INSTRUCTION ERROR!!
DIVIDE BY ZERO ERROR!
PRIVELLAGE VIOLATION!
LINE 1010 EMULATION!!
LINE 1111 EMULATION!!

(Source: Original TCRF research)

Music Tracker

Shows the notes being played in a song, and if any sound effects are applied, they are shown at the bottom.

Function 000784e2 contains the logic for outputting this data to the screen. Since it doesn't include code to actually setup the screen, we can reuse the interrupt handler code for that, then call the music tracker function during the main game loop, with the following changes:

0006a3d2 = 4e f9 00 00 08 7e ; jump into the interrupt handler
00000972 = 4e f9 00 06 a4 18 ; after loading font, jump back to the main game loop
0006a412 = 4e 71 4e 71 4e 71 ; skip loading title screen graphics
0006a428 = 4e 71 4e 71 4e 71 ; same as 0006a412
0006a45e = 4e 71 4e 71 4e 71 ; same as 0006a412
0006a49c = 4e b9 00 07 84 e2 ; call music tracker function

Additionally, this screen also requires the same overwritten bitmap font. Therefore, the full patch is available as a script.

Sound effect strings at 0x78622:

ARPEGGIO
PORT. TO
VIBRATO
SET VOL.
PAT.BREAK
SET SPEED

(Source: Original TCRF research)

Hidden Text

This string is located near the beginning of the ROM at 0x518:

Chars left:
RAM left  :
ROM left  :

This build date is located near the end of the ROM at 0x7F090:

Rom date:  30/03/96 1996