iNES Mapper 81

[NewRisingSun]

A previously undumped game (Super Gun by NTDEC) uses the following mapper registers: Edit 2: see wiki entry for updated information.

Code: Select all

$6000-$7FFF	..CC....	
$8000-$FFFF	....PP..	(bus conflicts, game writes $FFE0+X)
PP: Select 16K PRG ROM bank at CPU $8000-$BFFF (CPU $C000-$FFFF hard-wired to the last 16K bank)
CC: Select 8K CHR ROM bank at PPU $0000-$1FFF

The game's write sequence is as follows:

Code: Select all

	LDY	$15	; Current level number
	LDA	$C008,Y	; Bank register values, $01 $01 $06 $06 $0B $0B
	TAX
	STA	$FFE0,X	; PRG ROM switch
	ASL
	ASL
	ASL
	ASL
	STA	$6000	; CHR ROM switch

The fact that Kazzo's CNROM script only yields 8K of CHR ROM data confirms that the CHR ROM switch does not respond to $8000-$FFFF bits 0 and 1.

Does this resemble any existing mapper number? All the GNROM-look-a-likes I have seen use 32K PRG banks, not 16 KiB. If not, which new mapper number should I assign?

Edit: PCB images attached; clarified text.

[zxbdragon]

this rom dumped?
It is recommended to use UNIF

[NewRisingSun]

It is recommended to use UNIF

Actually, UNIF is deprecated, so its use is not recommended.

[zxbdragon]

I think the unif is right, nes 2.0 is out of date
Actually, Nes 2.0 is very bad, so its use is not recommended. nes 2.0 submapper have 15. 255 * 15 mapper number,is Very don't meet the requirements .

Nes 2.0 does not record the real hardware information, at the same time, this version is a temporary patch version 1.0.

[zxbdragon]

nes 2.0的submapper和PRAM,CRAM size 就是一个冲突。
完善unif才是王道。我更倾向于mame方式管理FC游戏。

Nes 2.0 submapper and PRAM, CRAM the size is a conflict.
Perfect unif is king. I prefer mame manage FC game.


this my dump game:
Unif: revision 8
Unif: board: COOLBOY
Unif: warning, skipping unknown chunk: "WRTR"
Unif: name: 360-in-1(CoolBoy) by www.nesbbs.com
Unif: dumped by: dragon2snow 4325692@qq.com
Unif: dump year: 2016
Unif: dump month: 1
Unif: dump day: 16
Unif: dumper agent: www.nesbbs.com
Unif: PRG-ROM 0 CRC: A095A8D7
Unif: PRG-ROM 0 size: 32768k
Unif: battery present
Unif: mapper controlled mirroring
Board: COOLBOY
Board: 32768k PRG-ROM
Board: 8k W-RAM
Board: 256k V-RAM
Board: MMC rev. B

this unif Record the information, but I think the record is not all .
nes 2.0 Is a no use outdated technology

[zxbdragon]

my dumped new game,According to the number of the PCB, don't have to think what MAPPER number, can be executed directly .

In Chinese "Nes 2.0 is chicken ribs" ,食之无味，弃之可惜。

[NewRisingSun]

Having studied all Nestopia mappers that use a 16K PRG ROM switch and having found none that matches the above description, and having neither found a mapper that would be compatible even when taking advantage of the fact that the game writes both PRG and CHR bits to both $6000 and $FFE0, I propose assigning mapper 81 for this board. I prefer not to use a mapper number 256 or higher for a 1992 non-multicart game.

Mapper 81 is unimplemented by FCEUX, Nestopia, Mednafen [1] [2]; it is not listed in the wiki's mapper grid nor in Kevin Horton's mapper grid. The single mention of it I found is in the old fwNES mapper list from 1998, in which it is described as "Tatio C075 [sic]", without listing any game that uses it.

Any objections? If not, then I will create the INES Mapper 081 page on the wiki and post a Nintendulator mapper source file and a Kazzo dumping script. I may also submit the CRC32 info to NesCartDB if I can figure out the submission process.

[Sour]

I went through my code as well and found no mapper that matches this. Afaik, mapper 81 is not used in any emulator.
For what it's worth, the mappers in light gray in this grid are mappers I have been unable to find any information nor valid roms (as of a couple of months ago), so they are probably safe to use.

[zxbdragon]

Only one game of a mapper ?

[NewRisingSun]

As promised, wiki mapper description, Nintendulator mapper source and Kazzo dumping script (rename to .ad) attached.

Edit: replaced mapper emulation source code with updated code reflecting how the hardware actually provides said functionality.

[Memblers]

That's the number I was using for my next mapper, but emulating it is the least of my concerns, so I guess it doesn't matter much. Not listed in any thing I've posted publicly (at least I don't think so).

[Pokun]

nes 2.0的submapper和PRAM,CRAM size 就是一个冲突。
完善unif才是王道。我更倾向于mame方式管理FC游戏。

Nes 2.0 submapper and PRAM, CRAM the size is a conflict.
Perfect unif is king. I prefer mame manage FC game.

Where exactly in NES 2.0 is this conflict?

UNIF has lots of cool metadata like controllers and such, but even that is incomplete and therefore not very useful.
NES 2.0 may be messy because it's designed to be backward compatible with the insufficient iNES format, but it looks to me that it solves the problems that UNIF failed to solve with both licensed and unlicensed games. The authour of UNIF recognized it's drawbacks and even requested it to not be used.

I think UNIF is the chicken ribs here that needs to be thrown away.

[zxbdragon]

nes 2.0 is the chicken ribs here that needs to be thrown away.

[Pokun]

Without any motivation to back them up, your words don't hold any water.

Right now it just sounds like you like the MAME-like metadata stuff that UNIF has, disregarding practical use.

[NewRisingSun]

On the subject of NES 2.0 vs. UNIF: I'm planning to make a post about assigning NES 2.0 mapper numbers (256+ for non-Chinese/512+ for Chinese) for all those boards that so far are UNIF-only. For that purpose, I will also post a UNIF->NES 2.0 converter.

Nes 2.0 is very bad, so its use is not recommended. nes 2.0 submapper have 15. 255 * 15 mapper number,is Very don't meet the requirements.

NES 2.0 has 4095*15 mapper numbers,is Very do meet the requirements.