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Hello, I am currently currently implementing MMC1 and able to play at least a few of the games without really noticeable glitches. However when I tried to play Metroid, I found a bug in my emu where it uses an incorrect nametable mirroring for the first tunnel. The screen just before the bugged tunn...

Thanks for the reply tokumaru! Thanks for the info about the mirroring. I already have some of those masks already implemented in other parts of my emulator (ex: Using $E7FF to perform mirroring for CPU addresses in $0000-$1FFF range). Saves a lot of unnecessary writes (I used to have code that writ...

Okay I was able to make the test pass by subtracting the palette address by $1000 and then applying nametable mirroring to the subtracted addres. Thank you for your help!

Thank you for your reply thefox. Okay so the palette value doesn't go into the buffer, instead, the value from the mirrored nametable that is "behind" the palette. My question is, how exactly is this mirrored nametable address computed from the palette address? Is it just palette address -...

Hello, It's my first time here in the forums and it has provided a lot of help for us aspiring emulator developers. Currently, my emulator's failing on Blargg's vram_test with an error code of #6 (Palette read should also read VRAM into read buffer) Digging the test's source code I have outlined fro...