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venkat24 / tvp

A Nintendo GameBoy Emulator written in C++17 and SFML
MIT License
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CPU bug on Tetris Level Select Screen #13

Open venkat24 opened 5 years ago

venkat24 commented 5 years ago

Reason hasn't been investigated yet, but the CPU seems to go wonky and start writing to Echo RAM at the Tetris level select screen.

Repro: Run the Tetris World ROM and attempt to select a level.

venkat24 commented 5 years ago

I've made some progress on investigating this, it fails because there is no implementation for the TImer Interrupt.

https://gbdev.gg8.se/wiki/articles/Timer_and_Divider_Registers

venkat24 commented 5 years ago

This doesn't seem to be due to the timer.

I've added a rough timer implementation which triggers timer interrupts correctly and yet the CPU is still glitching out.

venkat24 commented 5 years ago

Looks like this will be greatly aided by a debugger.

The priority is to have a working debugger with input mocking, so that we can easily examine memory and code during the execution of Tetris