Gunfight doesn't always work and will result in black screen and audio noise

stella-emu / stella

A multi-platform Atari 2600 Emulator

https://stella-emu.github.io

GNU General Public License v2.0

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Gunfight doesn't always work and will result in black screen and audio noise #491

Closed mi7chy closed 5 years ago

mi7chy commented 5 years ago

Happens intermittently with both 64 and 32-bit Stella-6.0.1-windows.zip on Windows 10 Pro x64 and Gunfight NTSC from the link provided below. For comparison, wasn't able to replicate the issue with z26 3.02.01 for Windows.

https://www.atariage.com/software_page.html?SoftwareLabelID=1627

sa666666 commented 5 years ago

Not entirely sure if this is a bug in emulation yet, since it also happens in Stellerator. More research is required.

thrust26 commented 5 years ago

That's because of the "copy protection" in the ROM which assumes that the carry flag is clear.

Disable randomizing CPU "PS" register in "Developer settings" and the "bug" is gone.

mi7chy commented 5 years ago

Can confirm thrust26's suggestion seems to have fixed the issue. Much appreciated.