80386 emulation vs Megarace cutscenes?

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

80386 emulation vs Megarace cutscenes?

Postby superfury » 2017-12-03 @ 13:59

For some reason, the 80386 emulates fine, but the megarace cutscenes stopped working at some point? BIOS and testsuites give no problem. The Sound Blaster isn't giving any sound for some odd reason? Can a problem with the Sound Blaster 2.0 emulation give problems with the Megarace cutscenes?

The first picture of every cutscene does show up, but no sound is played back and the visuals aren't updated? Anyone knows more about that? The animations for fade out and fade in of the scenes does apply without problems(for each of the three cutscenes loading the game)?

Edit: Just tried the old hardware(from back when Megarace cutscenes were working) with the new CPU emulation. The cutscenes bug still isn't fixed. So that means it's purely a CPU problem?
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Re: 80386 emulation vs Megarace cutscenes?

Postby superfury » 2017-12-03 @ 15:37

I've just tried the old hard disk based copy of the Megarace demo(instead of the CD-ROM version), with the minimal parameters(Just Sound Blaster sound and subtitles enabled, all other stuff(like HIMEM.SYS RAM etc.) is disabled). It just runs the cutscenes without problems?

So could that mean it's just a simple problem with the CD-ROM emulation? There's also a strange problem with swapping CD-ROM disks causing the CD-ROM controller to fail somehow? Anyone can see what's going wrong?

Edit: Disabling this behaviour(making it like Bochs) makes to not give an interrupt and only changing the ready status makes it unable to detect the disk has changed, but enabling the behaviour makes it hang on CD-ROM disk changes instead?

Edit: Just took a look at Dosbox-X: https://github.com/joncampbell123/dosbo ... re/ide.cpp

It seems to have a whole lot of commands following each other? Won't the driver crash on those as well?
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Re: 80386 emulation vs Megarace cutscenes?

Postby superfury » 2017-12-04 @ 05:58

I've just implemented that method, but MS-DOS 5.0a doesn't see the disk to change it's directory listing at all?
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Re: 80386 emulation vs Megarace cutscenes?

Postby leileilol » 2017-12-05 @ 03:39

I've seen the cutscenes be really really choppy on an actual 386sx long long ago (with a 2x CD-ROM) so I wouldn't be too worried about this.
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Re: 80386 emulation vs Megarace cutscenes?

Postby superfury » 2017-12-13 @ 09:43

Does there exist a MS-DOS program(for up to 80486 CPUs) that checks CD-ROM drive functionality(with iso image for checking disk reads)? I want to know if the CD-ROM drive emulation is faulty in some way.
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Re: 80386 emulation vs Megarace cutscenes?

Postby superfury » 2017-12-14 @ 13:13

I've just tried copying the CD-ROM disk contents containing the demo to the hard disk within the emulator, then extracting them using WinImage(harddisk) and WinISO(CD-ROM) and used WinMerge to compare the files. Both check out to be identical? So the CD-ROM emulation itself is working properly(although not getting past the initial Inquiry command using OAKCDROM.SYS, but does get passed on VIDE-CDD.SYS?), but Megarace itself has some odd problem with it's CD-ROM support somehow?
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Re: 80386 emulation vs Megarace cutscenes?

Postby superfury » 2017-12-14 @ 18:04

It seems that my most recent changes have fixed the Megarace cutscenes(which are mainly CD-ROM bugfixes and setting Megarace up correctly(to use the correct Sound Blaster IRQ 5/DMA channel 1 settings).

With those changes, Megarace seems to work in all configurations, both demo and actual game alike :D
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Re: 80386 emulation vs Megarace cutscenes?

Postby superfury » 2017-12-17 @ 00:09

One thing I noticed with Megarace as well: having installed less than 2MB RAM(requirement of the game) also makes the cutscenes fail, but continue on to the main menu/game itself? Shouldn't it terminate with an out-of-memory error? (1MB tested, which happens switching between 80(1)8X processors and 286+ CPUs due to memory automatic redetection(due to memory block size changing from 16 bytes to 64K for BIOS requirements)).
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