Re: Vs. DualSystem
Posted: Mon Dec 31, 2018 11:42 pm
There is no mapper 0 Vs. System game. If you find one, it is a bad header.
The mapper 0 hardware is defined as "no PRG bankswitching, no CHR bankswitching" and that cannot happen on the Vs. System board: it is physically laid out such that you can't not have CHR bankswitching. It's not like putting an 8 KiB CHR ROM in a CNROM board and having a latch that does nothing: instead there are two physical sockets, and you can only put an 8 KiB (or smaller, but that was never done) ROM in each socket or fail to put anything in that socket: The result is still mapper 99 and the empty socket results in open bus.
It may work as mapper 0, in the same way emulators don't "have" to enforce bus conflicts on discrete logic mappers, but it's incorrect.
MAME's database is in https://github.com/mamedev/mame/blob/ma ... /vsnes.cpp
To convert common names to MAME codename, go to the bottom with the GAME macro.
To convert MAME codename into dipswitches, look for INPUT_PORTS_START( codename )
To convert MAME codename into ROM sizes and hashes, look for ROM_START( codename )
The mapper 0 hardware is defined as "no PRG bankswitching, no CHR bankswitching" and that cannot happen on the Vs. System board: it is physically laid out such that you can't not have CHR bankswitching. It's not like putting an 8 KiB CHR ROM in a CNROM board and having a latch that does nothing: instead there are two physical sockets, and you can only put an 8 KiB (or smaller, but that was never done) ROM in each socket or fail to put anything in that socket: The result is still mapper 99 and the empty socket results in open bus.
It may work as mapper 0, in the same way emulators don't "have" to enforce bus conflicts on discrete logic mappers, but it's incorrect.
MAME's database is in https://github.com/mamedev/mame/blob/ma ... /vsnes.cpp
To convert common names to MAME codename, go to the bottom with the GAME macro.
To convert MAME codename into dipswitches, look for INPUT_PORTS_START( codename )
To convert MAME codename into ROM sizes and hashes, look for ROM_START( codename )