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PostPosted: Sat Apr 21, 2018 4:04 pm 
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Location: Seattle
Point taken, tepples. Even so, disabling the CIC stunner is a different class of behavior, and one that doesn't really affect emulation.


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PostPosted: Wed Apr 25, 2018 2:53 am 
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Joined: Thu May 19, 2005 11:30 am
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For what it's worth, here is the cover art of LF36 from Whirlwind Manu's catalog, in case that helps tracking down the "true" LF36.

(And while you're at it, check out the description of "Volleyball" on a different catalog page.)


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PostPosted: Mon Apr 30, 2018 3:10 pm 
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Small update to the mystery of the two remaining unknown versions. This version (let's call it "Version C", headerless CRC32 0xEA7682A9):
NewRisingSun wrote:
Unknown publisher, named Super Mario Bros. 2j (Unl) [U][!].unf in GoodNES. 80 KiB PRG-ROM, 8 KiB CHR-ROM. Full title screen with eight stars and 1986 Nintendo copyright. Has Button A-World A1 cheat. Crash-proneness untested. I wanted to assign this to Mapper 311, but wanted to wait until further hardware info is available on the others.
seems to be a hack or bad dump of this version (let's call it "Version D", headerless CRC32 0x4F9BF9BC):
NewRisingSun wrote:
Unknown publisher, named Super Mario Bros. 2 (J) (LF36) [p1].nes in GoodNES. 80 KiB PRG-ROM, 8 KiB CHR-ROM. Full or blank title screen (with cut-off left cloud) depending on DIP/Solder-Pad setting, copyright year 0986 instead of 1986, with eight stars. Crash-proneness untested. Has Button A-World A1 cheat. Mapper 43. May be hacked from 128 to 80 KiB PRG.
Version C and Version D write the same values to the $4022 PRG banking register. But:
  • Version C is what Nestopia expects Mapper 043 to be (calling it SMB2J (c)); Nestopia Plus calls it "UNL-SMB2JX". It must switch the entire 32 KiB from $8000-$FFFF to run at all. Even then, the game goes crazy at the beginning of World 5-1, causing the player to immediately die in an empty sky stage, which is why it should be considered a bad dump. It cannot be bad emulation of a good dump, because the data that is supposed to be selected by $4022's $05 value is not present at all in the image, notwithstanding GoodNES' [!] tag, which seems to be completely worthless at this point. This version therefore should not be emulated under any mapper number.
  • Version D is what FCEUX expects Mapper 043 to be, and must switch only the 8 KiB from $C000-$DFFF. World 5-1 works, but only if the lookup table for the lowest three $4022 bits to the actual 8 KiB PRG-ROM bank is 4,3,4,4,4,7,5,6, as Nintendulator does it. FCEUX' source code has this table commented out and uses a table of 4,3,5,3,6,3,7,3 instead, which causes the game to crash in World 5-1 just like version C. The 4,3,5,3 table is however correct for Mr. Mary 2, which writes entirely different values to the $4022 bankswitch registers ($06 for world 5-1 and $02 for world A-1). This of course means that Version D and Mr. Mary 2 should not coexist under that same Mapper 043. One could move one of them to Mapper 311, or to a submapper. Then again, because Version D has CHR-ROM and Mr. Mary doesn't, one could use that to distinguish the two and use the correct lookup table for each one.
Remaining mysteries are what the deal with Version D's DIP switch is (according to Nintendulator), why version D displays a 0986 rather than a 1986 copyright date, and why Version C displays the correct 1986 date even though it otherwise seems to be a bad dump of Version D.


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