Home Page Forums Other Emulator Message Boards Nestopia I would like to report a bug with the emulator

I'm working on my own rom hack of megaman 3 for the NES. And everything's been fine and all, until very recently my game just doesn't seem to work anymore in nestopia. I'm most certain that it is a problem with the emulator and not my game but what happens is whenever i load it up, the screen is completely green, like the background just totally doesn't show up but sprites do work at least. And then when I go to the stage select screen, it totally freezes/crashes.

This just begun happening ever since the way how i load chunks of data from the ROM into the RAM, $6000-$7FFF area, and then read/write from there instead of the ROM banks.

My hack uses the MMC5 (mapper 5). This problem does not happen in other emulators like fceuxd and nintendulator. And like from what I understand nestopia is meant to be the most accurate of any emulator. But I think i found this problem though.
This is on the latest nestopia 1.40 version.

Yes, it is. Which means that your hack probably like doesn't work on real hardware.

Edit: I'm kind of interested in your hack, though. What's it about? Final Fantasy?

I think NST doesn't like iNES format ROMs that aren't in it's internal database. There was a similar issue with the translation of Kid Dracula where you must run it as "unmodified ROM + ips/ups patch" or it doesn't boot.

if it works in nintendulator as he claims, then probably it would work on the real thing as well.

Freaky. If it's like RB says, is there anything that can be done to make NST behave in a somewhat saner manner, like defaulting to what the iNES header says rather than flipping out?

Well I honestly would test on a real NES if i had the chance, but I do not own one though. And guessing it would probably be very difficult if other people tried since it must be very rare to find any MMC5 boards.

Perhaps the OP is coincidentally (?), brought on by this:
July 24, 2008

And this:
August 3, 2008

-Trebor

Nestopia is more sensitive than most emulators in terms of the INES header. In particular, the WRAM field (byte 8) is a source of problems, especially with mappers that support larger WRAM sizes (like MMC5). Be sure the WRAM field is set to a non-zero value. Supported values for MMC5 are 1 (8KB), 2 (16KB), 4 (32KB), and 8 (64KB).

Uh oh im sorry it was my fault, not the emulator. I coded a little routine that changes the RAM page to 01 (#04 written to $5113), write some bytes, then read the first one. If it did not match, then my game would return an error message as follows:

http://www.a3share.com/members/1119/ramtest.PNG

If it did match, then the rom would load normally. After that $5113 is set back to #00.

until I discovered that this was all because I never actually wrote to $5113 in the RESET code, so that's why. So I added a 00 write to 5113 in it, and then now nestopia loads my game properly now with no problems.

Sorry about that. My mistake.

I have to hand it to you, that's actually pretty cool that your hack does error checking for the cartridge that it's on (at least I'm guessing that's what it means).