Should have a T&L card to emulate so there's much less triangle math to be done by the emulator cpu 😀

I've got some questions and suggestions about PCem ROMs.

Readme.txt lists what ROMs are needed for the systems emulated, but...

- IBM XT lists as necessary two files (5000027.u19 and 1501512.u18), but looking into PCem.exe, it list three files (roms/ibmxt/xt.rom, roms/ibmxt/5000027.u19 and roms/ibmxt/1501512.u18). They seems not needed (IBM XT runs without xt.rom) but what are they used for?
- IBM AT: needs 62x0820.u27 and 62x0821.u47 instead of at111585.0 and at111585.1.
- EuroPC: Lists two files as needed for EuroPC, but only one is used (50145).
- Ami386: needs ami386.bin instead of ami495.bin.
- Ami486: needs ami486.bin instead of ami1429.bin.
- Unlisted files: roms/hot-433/hot-433.ami, roms/5429.vbi, roms/86c764x1.bin roms/86C732P.bin, roms/ibm_vga.bin.
- Location of rom files seems arbitrary at times. Every system BIOS is located on a folder, which seems consistent; but video BIOSes are outside folders (what about a roms/video folder?) except mach64 (has its own folder) and mda.rom (outside roms folder, on the same folder that PCem executable). What about using a roms/video folder?
- Can the full path be included on readme.txt (i.e.: roms/ibmxt/1501512.u18)?
- Could you add an options to add paths for BIOS and disks?
- How can I disable XT-IDE BIOS without erasing it?
- Is the Acer386 OTI BIOS the same as the "normal" OTI67 BIOS? It is really needed on the acer386 folder?
- How about including CRCs or md5 of tested ("recommended") ROMs? I copy ROMs from MESS to PCem folders, but I'm not sure if that files are the same.

Thanks.

Zup wrote:

I've got some questions and suggestions about PCem ROMs. […]
Show full quote

I've got some questions and suggestions about PCem ROMs.

Readme.txt lists what ROMs are needed for the systems emulated, but...

- IBM XT lists as necessary two files (5000027.u19 and 1501512.u18), but looking into PCem.exe, it list three files (roms/ibmxt/xt.rom, roms/ibmxt/5000027.u19 and roms/ibmxt/1501512.u18). Other systems also suffers from files not listed but referenced on .exe. What about those files? They are not needed (IBM XT runs without xt.rom) but what are they used for?
- Readme.txt says that two files are needed for IBM AT (at111585.0 and at111585.1), but it won't work unless you use 62x0820.u27 and 62x0821.u47).
- Also, it lists two files as needed for EuroPC, but only one is used (50145).
- Location of rom files seems arbitrary at times. Every system BIOS is located on a folder, which seems consistent; but video BIOSes are outside folders (what about a roms/video folder?) except mach64 (has its own folder) and mda.rom (outside roms folder, on the same folder that PCem executable). Can the full path be included on readme.txt (i.e.: roms/ibmxt/1501512.u18)?
- Could you add an options to add paths for BIOS and disks?
- How can I disable XT-IDE BIOS without erasing it?
- How about including CRCs or md5 of tested ("recommended") ROMs? I copy ROMs from MESS to PCem folders, but I'm not sure if that files are the same.

Thanks.

(Still checking ROMs, may add more items later)

I'm with you on this one.

The other day when I was running Windows NT 3.51 in PCem and I ran into a message telling me to "Press CTRL-ALT-DELETE to logon" when I pressed CTRL-ALT-DELETE, it affected the host machine!

Sarah, can we add a Soft Reset option in the File menu that will simulate the CTRL-ALT-DELETE keys in the guest machine without affecting the host?

Also, do we have any generic 80286, 80386 and 80486 Phoenix BIOS based generic machines that can be tested?

leileilol wrote:

This virge emulation is cool stuff 😀

Glad to see some other old-school graphics standards emulated. Does anyone have a list of games with Virge support, Wikipedia doesn't list them beyond: Terminal Velocity, Descent II, Tomb Raider and MechWarrior 2.

I have no idea :\

leileilol wrote:

I have no idea :\

Ah duh, thanks.

Love this project, just a quick question. Is PCem a fork of DOSbox or just a project that shares some code? Like, as for hardware emulation, why is it, to me, that the list of emulated hardware in DOSbox is wider than what PCem emulates. Or am I wrong?

Found a possible error. Some sector shifting appears to be happening.
When you do an imgmake yourfile.img -t hd_4gig -fs fat32 this is reported by dosbox

1Sectors=63
2
3Heads=130
4
5Cylinders=1023
6
7Total Size=4032mb 

When you input those perimeters, heads max out at 128, into PCem it reports the size to be 4028MB instead of 4032MB

Also, selecting Diamond Stealth 3D 2000 (S3 ViRGE) gives a black and white bios and desktop, yet the windows boot screen, windows 95, is on colour. I have it on DirectDraw

dosquest wrote:

Love this project, just a quick question. Is PCem a fork of DOSbox or just a project that shares some code? Like, as for hardware emulation, why is it, to me, that the list of emulated hardware in DOSbox is wider than what PCem emulates. Or am I wrong?

Completely separate project. The only DOSBox code used is the OPL emulator.

Oh, ok. 😒

Another thing I noticed, maybe it is because I am running this on a core i-7 with hyperthreading but, if I pick a bios that does not have Intel chip support, either a winchip, cyrix, amd etc, anything that is not Intel, and I enable APM in bios, I can't seem to enable cpu power management. Why would I want to? You ask, well I have noticed that the emulated CPU speed ranges from 105% to 75% when running windows 95C, DOOM2, ROTT, DOOM1 in either pure 6.22 DOS, or in dos mode in windows 95, but if I have an Intel chip enabled and I enable the Intel APM and tell it to automatically manage power, when I run a program I do not experience as great a drop in CPU speed. Little note, when running an Intel chip with power management on, if I enable sleep in the start menu, click sleep it will cycle VGA then lock the cpu in 100 to 105% emulated speed. 😒 Just wish there was a BIOS with PNP for the CD-ROM and Intel support with APM so I could get the 100 to 105% I need. 😜 Too bad I know nothing about reverse engineering hardware 🙁

I have found it is to do with high refresh rate, if I am playing a game with a quick refresh rate, cough DOOM, cough, it drops the CPU speed to 54%, or if I am highlighting the desktop and moving the selection box around it drops the CPU speed.

The reason why I brought it up was that if the speed drops below 90% or fluctuates wildly I end up with sound skipping and sound doubling.
What I have possibly tracked it to is the accelerated desktop. The least worse setting is Award SIS 496 with a Cyrix chip at 133, one notch down from full accelerated desktop and all shadowing options in bios enabled. I will write up a more comprehensive guide later, but it is 1am currently.

Ok, I must be really tired. Ok, the proper BIOS with semi ok performance would be 430vx pci with the WinChip 240, but then it still fluctuates. I hope anything I have said has helped in some way.

The emulated speed drops because PCem is currently quite slow. Just emulate slower CPUs for now; the faster CPUs won't be usable until I've got the recompiler into reasonable shape.

It sounds like you have progress toward a recompiler. That's wonderful news if so! The different types of recompilers are very interesting, especially the capability to adapt to other cpu architectures.

Ok, thanks. If there are any SVNs or alpha,beta builds you want me to test I would be delighted to do so.

Another glitch, when emulating a cyrix brand pentium, quake for windows, win95 port, does not correctly identify it as a pentium. Though it is running as a 496, it still says it is an 486.

Cyrix doesn't make Pentiums. "496/497" has nothing to do with the CPU.

This is not a bug nor is it a glitch.