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PCem v13.1 observations and bug report

Posted: Thu 25 Jan, 2018 6:10 pm
by mbrown3345
Greetings all - first post here, so please bear with me.

First of all thanks to the devs for the amazing emulator, PCem is really in a league of its own, especially when it comes to emulating Win95/Win98 era PCs with 3dfx.

Still, I'd like to list a couple of observations of items that appear to malfunction in version 13.1, and seemed to work fine in ver 12.

My host PC config is i7-8700/32G RAM/GF1070/Win10

1) Visible interlacing of mouse cursor under Windows 95 OSR2 (see attached screenshot). Same with both S3 Trio 64 and Diamond Stealth. Only visible when moving the mouse. Tried all kinds of emulator settings (OpenGL, D3D, etc.) and different Win drivers - no effect

2) Emulation of 486 CPUs other than AMD, i486DX4-75 or i486DX4-100 does not seem to work for protected mode DOS games. Doom, HoMM and others hang at launch with CPU set to anything but AMD or i486DX4-75/100 (including Cx486, and i486-DX2/66). Tried this both with or without Dynamic Recompiler enabled and AWARD Sis and Clone 486 BIOS - same result. Changing CPU to i486DX4-100 resolves the issue immediately without even needing a reboot. Real mode games don't seem to be affected. Changing the CPU to Cx486DX2-66 after the game has launched seems to work just fine, so the problem may be with DOS4GW extender

3) Very minor - when using custom resolution and scaling (4:3, integer, etc.), switching back/forward from full screen will result in a black border around the screen in Windowed mode. Selecting custom resolution from menu fixes it

Re: PCem v13.1 observations and bug report

Posted: Thu 25 Jan, 2018 7:45 pm
by gen_angry
I posted about your #2 bug here as well: https://pcem-emulator.co.uk/phpBB3/view ... f=2&t=2863

It has to do with the dynamic recompiler, try turning it off. Its slated for a rewrite next version.

Re: PCem v13.1 observations and bug report

Posted: Thu 25 Jan, 2018 7:49 pm
by SarahWalker
mbrown3345 wrote:
Thu 25 Jan, 2018 6:10 pm
1) Visible interlacing of mouse cursor under Windows 95 OSR2 (see attached screenshot). Same with both S3 Trio 64 and Diamond Stealth. Only visible when moving the mouse. Tried all kinds of emulator settings (OpenGL, D3D, etc.) and different Win drivers - no effect
What resolution were you using here? It's possible that the cards you used were actually in interlaced mode.

Re: PCem v13.1 observations and bug report

Posted: Thu 25 Jan, 2018 10:11 pm
by leilei
I don't think 2) is recompiler related. I've seen Doom hang on start on AMI386 with AM386 and Cyrix486SLC processors (with MSDOS 6.22, SBProv2,ATI-28800), unfortunately seemingly at random. It's more consistently starting up on the AMI WinBIOS 486 and SIS496 boards and I don't believe specific fast processors matter for that.

Re: PCem v13.1 observations and bug report

Posted: Thu 25 Jan, 2018 10:33 pm
by mbrown3345
I’m using 1024x768 under Win 95, but the behaviour is still present but less observable in 800x600. PCem 12 does not have this issue in either res

As for the hang bug - I don’t think it’s recompiler related as it happens even with dynamic recompilation explicitly turned off