Unused Game Content Code Programming Super Game Boy BIOS F5 Example Pro Mahjong Kiwame GB プロ麻雀 極GB

Channel:

nensondubois

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Published on February 7, 2012 11:32:05 PM ● Video Link: https://www.youtube.com/watch?v=v9ENpaBlMnE

Game:

Pro Mahjong Kiwame 64 (1994)

Duration: 0:34

2,937 views

5

Set Command F5
01 of F5.00.00.00 7E.01.00.00 00.00.00.00 00.00.00.00

It will read out the following listed (F0-FF F6 5 command) Super Game Boy commands instantly. File register transfer data is not sent to the SNES as they require a 4 frame wait instance.

Example used: Pro Mahgong Kiwame GB Title Screen Select VS Mode and replace SOUND 41 Command with F5 and the palette will change sporadically and a SOUND function will play. Here is the command listing read out after replacing 41 with F5 (F0-FF).
F6 Command was used in testing for this video demonstration) The Command isn't technically finished. The SNES will still read the function and the rest is a complete mystery. I do not have a proper explanation for why it exists but it is definitely unused Super Game Boy/2 BIOS code that reads from the Game Boy JOYPAD registers. It may have been an oversight on Nintendo/HORI's part in which they originally used the command for testing various SGB commands. It is unclear and it likely shouldn't exist. It appears to be remnant of code Nintendo was testing for probable JOYPAD I/O read functions and nothing more.

ROM Changes made to Pro Mahjong Kiwame GB for testing F6 Command:
Patch ROM Address 0x3FC8 to F6: Game Boy Game Genie code: F6F-C8C-E6F

Super Game Boy Command Functions Set:
6 1E unknown
F6.09.00.03 00.00.00.00 00.00.00.00 00.00.00.00 - Actual Command used to read following proceeding (Number determined by F0-FF; F0 does not read any commands) in ROM listing and the command itself is ignored and so are all non-sequential commands (ATTR_CHR), and null spaces in packet commands.)
00.00.00.00 00.00.00.00 E1.0A.2A.88 E0.80.F9.88 - Set Palette
00.00.00.00 00.00.00.00 76.90.E2.58 C1.E9.35.AD - Set Palette
00.08.00.80 00.00.00.00 FB.3E.FF.CD 1F.7F.21.15 - Set Palette
40.11.12.40 FA.EC.C7.C3 76.07.C3.B3 03.5B.40.5A - Set Palette
41.02.44.49 45.52.47.06 48.56.48.C3 48.45.49.3E - Set SOUND

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