Any good MS-DOS 80386/80486/Pentium(on slow system) games for testing Protected mode emulation and instructions?

Emulation of old PCs, PC hardware, or PC peripherals.

Re: Any good MS-DOS 80386/80486/Pentium(on slow system) games for testing Protected mode emulation and instructions?

Postby superfury » 2019-8-07 @ 20:13

Hmmmm... Something is going strange when testing paging on the Pentium emulation, running debian 3.0r0(from https://sourceforge.net/projects/bochs/ ... n%20Linux/)? Trying to run it on the Pentium emulation makes the emulator somehow lock up, because the Paging TAG generation(which is used for looking up the entry and storing it) WILL set bit 0 to 1(the present bit) when saving the TLB entry. But when reading the TLB entry from the paging TLB, somehow all bits are correctly set in the tag to look it up, but bit 0 is reset? Even though the basic expression used is:
Code: Select all
//W=Writable, U=User, D=Dirty
OPTINLINE uint_32 Paging_generateTAG(uint_32 logicaladdress, byte W, byte U, byte D, byte S)
{
   return (((((((((S<<1)|D)<<1)|W)<<1)|U)<<1)|1)|(logicaladdress & 0xFFFFF000)); //The used TAG(using a 4KB page, but the lower 10 bits are unused in 4MB pages)!
}


Why is it clearing bit 0? All other bits are correctly set, but bit 0 is reset?

The only thing following it is:
Code: Select all
      TAG &= (curentry->entry->addrmask|0xFFF); //The full search mask, with the address width(KB vs MB) applied!


Where curentry->entry->addrmask is 0xFFC00000 due to it being in a 4MB TLB entry? But that still has bit 0 set, but it's still cleared after these two lines(Paging_generateTAG and the TAG &= (curentry->entry->addrmask|0xFFF); ? Why is this happening?

Edit: Managed to fix it. It seems a problem with the mask to be applied(for searching tags and masking off bits that are to be ignored(e.g. writable and dirty bits in some cases for memory read accesses) was causing issues. Since the mask and the tag that's pre-masked for quick search weren't matching properly with 4MB entries, it was failing to properly recognise them when the upper bits were non-zero(upper 10 bits of the address(bit 12 to 21) that were added in the case of the 4MB pages).
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Re: Any good MS-DOS 80386/80486/Pentium(on slow system) games for testing Protected mode emulation and instructions?

Postby superfury » 2019-8-09 @ 19:11

For the software mentioned in: viewtopic.php?f=9&t=64389

Just tried the Into The Shadows demo. It seems to run fine, but very slow(of course, since it's running at 20% realtime speed).

Still need to test the other two.

Edit: ATP(Airline SImulator as peterferrie called it, if I'm not mistaken) seems to run fine. Just ran a little testflight. Everything seems to be working fine as far as I can see.

Edit: Hmmmm.... Greedy doesn't seem to respond to input? It gets to the main menu without issues, but unresponsive otherwise?
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Re: Any good MS-DOS 80386/80486/Pentium(on slow system) games for testing Protected mode emulation and instructions?

Postby superfury » 2019-8-11 @ 12:14

Hmmm.... After debugging some more on Basic Linux on the Pentium emulation, I see a 0x18 value being loaded into DS, which faults out due to a 0x00 being in the Access Rights byte?

Edit: Hmmm... Debugging some more I see the GDTR origianlly being at 906b4(Linear Address) with Access Rights 0x93(normal). Then 0x92 at C01BDFC0. Then 0x00 at the same base address?
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Re: Any good MS-DOS 80386/80486/Pentium(on slow system) games for testing Protected mode emulation and instructions?

Postby superfury » 2019-8-14 @ 16:29

Just retried OS/2(the same one as earlier). It says Loading on the second disk, then complains it cannot find "A:\COUNTRY.SYS" (without quotes)?

Anyone knows what the cause might be? I do see it using call gates, but they seem to work fine?
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Re: Any good MS-DOS 80386/80486/Pentium(on slow system) games for testing Protected mode emulation and instructions?

Postby superfury » 2019-8-28 @ 13:18

Hmmmm... Something weird happened to the Day of The Tentacle (Maniac Mansion 2) for MS-DOS. When starting the game, it seems to somehow hang at a black screen?

Is this perhaps related to the fix of the loading of SS:ESP when bopping down to user mode from kernel mode?
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Re: Any good MS-DOS 80386/80486/Pentium(on slow system) games for testing Protected mode emulation and instructions?

Postby superfury » 2019-9-06 @ 09:01

Yay! Having fixed the x86 protected mode breakpoints, NT 3.1 now continues past it's hard diskmcheck(chkdsk reports they're clean)! :D

Edit: Yay! It properly starts the GUI part of the setup! Mouse cursor confirmed!

Edit: Mouse works! It gives a message box(using ET4000, perhaps VGA during the first part of setup): "The system isn't properly configured. Please run setup again".
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Re: Any good MS-DOS 80386/80486/Pentium(on slow system) games for testing Protected mode emulation and instructions?

Postby superfury » 2019-9-24 @ 05:30

Tried installing Rayman (The first) for MS-DOS(Although had to download a cue/bin due to the disk imaging software refusing to properly read in my CD-ROM(probably because one or more of the sectors before the volume boot record is damaged) and keeps throwing read errors, refusing to continue even though pressing retry again and again).

The installer seemed to run without errors. Then, when selecting the play option from the menu, I see a quick loading in a bit of Doom-styled header for a flash, then it dumps me back to the MS-DOS prompt saying "MSCDEX is corrupted"? What's up with that? I'm using a combination of Windows 95 OAKCDROM.SYS(instead of VIDE-CDD.SYS due to CD-ROM error reporting issues with VIDE-CDD) and MS-DOS 6.22's MSCDEX.EXE? Or should I use Windows 95's MSCDEX? Why is it complaining about MSCDEX?
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Re: Any good MS-DOS 80386/80486/Pentium(on slow system) games for testing Protected mode emulation and instructions?

Postby superfury » 2019-9-29 @ 19:04

Tried booting the current(?) i386 debian kernel on UniPCemu from a converted disk image(version 2 qemu disk image). UniPCemu is configured for 12MB RAM.

I see it triple faulting during a BOUND instruction(lower limit 0x8xxxxxxx and upper limit 0x100 is weird)? I see a quick out of memory message during that, before triple faulting and rebooting?

The bound instruction SHOULD be fine, but why the triple fault(invalid/unset #gp/#df interrupts)?

Anyone?
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Re: Any good MS-DOS 80386/80486/Pentium(on slow system) games for testing Protected mode emulation and instructions?

Postby superfury » 2019-10-01 @ 05:38

Hmmm... Tried running MS-DOS 6.22 setup in a variety of settings/architectures: XT/8088, Compaq Deskpro 386 w/ 80386 and Pentium. All seem to hang during the checking the hardware step it starts with?

I also tried it with the currently improved MDA/CGA emulation(line drawing and 9-pixel wide fonts now properly working on MDA). But I notice there's no line drawing boxes etc. on MDA? Or is that a problem with Dosbox's 14-row character font? It seems like it's in the tables through?
Edit: Nope. It was a precalculation problem.
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Re: Any good MS-DOS 80386/80486/Pentium(on slow system) games for testing Protected mode emulation and instructions?

Postby superfury » 2019-10-01 @ 22:52

Just tried running MS-DOS 6.22 setup disk 1 of 3 on the 8088 XT emulation with MDA... It 'rebooted' into the BIOS, making the Turbo XT BIOS display an error message saying something like "error code nn"? Does that mean 6.22 can't run fully on a 8088, or that the 8088 is having a bug?
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Re: Any good MS-DOS 80386/80486/Pentium(on slow system) games for testing Protected mode emulation and instructions?

Postby superfury » 2019-10-10 @ 22:03

Just tried running PCCheck 6.0. It loaded partly, then notifying me that the FAT was bad (perhaps during a hard disk check)?
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