Gambler Jiko Chuushinha 2: Gekitou! Tokyo Mahjong Land Hen

Gambler Jiko Chuushinha 2: Gekitou! Tokyo Mahjong Land Hen
Developer: Game Arts Publisher: Game Arts Platform: Sega CD Released in JP: December 18, 1992 This game has a hidden developer message. This game has debugging material. This game has a hidden sound test. This game has hidden bonus content.

Test Mode

Present in files TEST.BIN, TEST.DAT, TEST.FCX is a test mode.

The sub CPU's initial program SSTART.BIN is loaded at program RAM address 0x10000, and conditionally loads TEST.BIN at 0x13800 depending on state read over the gate array at address 0x10090. Furthermore, TEST.BIN itself has a similar condition at the start. To always pass both conditions, apply the following patch on the data track:

0x67f94 = 4e 71 4e 71
0x6b626 = 22 3c

Pages can be switched by pressing A.

(Source: Original TCRF research)

Page 0

• Music/Sound/PCM audio can be played with an optional Fade out effect;
• Mentsu selects the person to display. Pressing C shows a pattern at the bottom, while B shows 4 patterns beginning on the index of the selected person;
• Auto Demo has no apparent effect;

Pressing Start exits test mode;

If an invalid music is selected, the screen flashes red, soft-locking the game.

Page 1

• Mentsu selects the person to display;
• Point sets the position offset on the grid to place the picture;
• Pattern will play a pattern sequence, while AnimePat shows a single frame of the sequence;
• Zoom/Rotate applies the corresponding transformations on the picture;

Page 2

• Drive opens/closes the CD tray;
• Both data and audio tracks can be played, along with Volume/Fader effects, but if the CD is not present, the track status stays on SEEK when attempting to play;
• Sub code = ON updates the time while playing a track, along with some CPU synchronization state;

Debug System

This needs some investigation. Discuss ideas and findings on the talk page. Specifically: Try to fix the rendering issue

On page 0, when we set option Debug System = ON and press Start, the file DEBUG.BIN is loaded into the main CPU's RAM address 0xfc0000.

This file contains what appears to be an interactive memory dump display. While tiles are placed on the VDP's foreground plane (which can be seen for example with BizHawk), they are never rendered on screen, which stays blank.

The memory dump offset can be tracked at RAM address 0xfc0c7a, which is updated with the following controls:

Down/Up	Increment / Decrement offset by 0x10
Right/Left	Increment / Decrement offset by 0x10000
C+Down/Up	Increment / Decrement offset by 0x100
B+Down/Up	Increment / Decrement unknown variable at 0xfc0c76

Debug Mode Leftovers

A single reference to address 0xe7f4 is present in file MAHJONG.BIN, and is only used to conditionally print the label DEBUG MODE at the bottom of the screen during a match. We can both set this address and bypass the condition with the following patch in the data track:

0x49634 = 33 fc
0x4963c = 4e 71 4e 71

README.DOC

A short message from one of the developers can be found by placing the disc into your computer.

　　　　　見るな～～～～～～～～～～～～っ

　　　　　　　　　　　　　　　　　　　　　　　　　　　　　Ｂｙ．開発者

The message translates to "Do not look at thiiiiiiiiiiiis! By. 'A Developer'".

(Translation: Bast)

(Source: GEAR/GEAR本館 Mega Drive Dataroom)