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Re: Emulating Area5150

Posted on 2023-06-19, 22:59

When does that first cycle apply? I'd assume it's not the fetching from prefetch of the CDxx opcode imm8 parameter? when executing INT0, INT1, or INT2, the first microcode instruction of INTR is skipped. INT imm8, INTO and INT3 do not skip this instruction. INT3 is a little weird as it skips a …

Re: Emulating Area5150

Posted on 2023-06-19, 13:31

The only parts not working are the two wavy images at the end (the one with the green guy, and the credits). Maybe this core really makes a separate scan conversation to VGA (I don't really know for now) so it is a problem of the simulated CGA. Thanks!. It does; you can look at the code for it here …

Re: Emulating Area5150

Posted on 2023-06-18, 17:02

It can load any BIOS ROM and run that (loading it at 1MB-size, starting execution at FFFF:0000 on the 8088/8086). What I found useful is loading an arbitrary binary blob at a specified location and running it directly. The way I know when to stop is if there is a fetch for a code byte outside of …

Re: DotXT

Posted on 2023-06-17, 15:54

xcomcmdr wrote on 2023-06-17, 15:53: You could try to run this BIOS: https://github.com/skiselev/8088_bios I'm a big fan of GLaBIOS too https://github.com/640-KB/GLaBIOS/

Re: Emulating Area5150

Posted on 2023-06-17, 15:44

I can check the video's raster position (the renderer's(think CGA programmed register from 0 to vtotal, in raw dot clocks(div 8 for character clock) and scanline counter) as well as the beam's(position on the raster that's drawn during said dot clock), displaying seperately) in UniPCemu (logged and …

Re: DotXT

Posted on 2023-06-17, 13:57

Jo22 wrote on 2023-06-17, 13:50: Another user here has trouble with the PC BIOS, too, maybe. The floppy controller wouldn't work with a Gotek, because BIOS/FDC hold a pin low for too long. Not sure it's really related, though. Happy user of a Gotek on an IBM 5150 here 😀

Re: Emulating Area5150

Posted on 2023-06-15, 14:24

Is anything special wrt VRAM addressing (CPU window or renderer MA) new since 8088 MPH used here? Not really. If you can run the rest of Area5150 I would assume your address handling is correct. The only tricky bit is the little split-frame thing they are doing which I explained in a previous post; …

Re: Emulating Area5150

Posted on 2023-06-13, 14:45

Awesome project! Now if someone could fix area5150 so that it runs on my 286, that would be nice :) It runs pretty far, but crashes at some point late in the demo. The 'Wibble' (Charlie Chaplin) and 'Lake' (End credits) effects will never run, unfortunately, as they are perfectly cycle-counted …

Re: Emulating Area5150

Posted on 2023-06-13, 14:09

There seems to be some corruption to the text in the CGA Compatibility Tester vertical scroll test, https://www.vogons.org/viewtopic.php?t=22555 Also the CGA game Prohibition has scrolling issues, I guess it just needs this port mirroring fix, https://www.vogons.org/viewtopic.php?t=18311 Both of …

Re: Emulating Area5150

Posted on 2023-06-13, 13:49

Yea, these improvements sound promising! I wonder though... do you actually have a system that runs the composite emulation at the full 60 fps? If so, what kind of specs are we looking at? I have a Ryzen 5900X CPU, so a fairly recent and rather high-end CPU. This is the performance view of the new …

Re: Emulating Area5150

Posted on 2023-06-11, 19:27

[*]With a CGA program running (and a screen full of content), why would the memory view show all zeros in the 16kb framebuffer at B800:0000? Curiously the MDA's 4kb at B000:0000 does seem to be full of '20 07's, i.e. a cleared screen. The memory viewer doesn't currently support MMIO; since the CGA …

Re: Emulating Area5150

Posted on 2023-06-11, 17:28

There seems to be some corruption to the text in the CGA Compatibility Tester vertical scroll test, https://www.vogons.org/viewtopic.php?t=22555 Interesting, I'll check it out. Also the CGA game Prohibition has scrolling issues, I guess it just needs this port mirroring fix, https://www.vogons.org/ …

Re: GloriousCow's PC Emulation Blog

Posted on 2023-06-10, 22:18

Could you please add Adlib / Soundblaster device? Eventually... How accurate is the VGA emulation? Not very; it is a "draw the VRAM every frame" sort of implementation, for speed, and there are many missing parts like CGA emulation, unchained modes, user-definable fonts, etc. All the registers are …

Re: Emulating Area5150

Posted on 2023-06-06, 16:39

Ticking the emulated CGA card at 14Mhz is expensive. In the current release of MartyPC, the CGA device takes 3x the CPU time to emulate than the CPU itself. I tried ticking the CGA by character clock, which would mean I could update the card at 1.79Mhz instead of 14Mhz. This worked for all of …

Re: Emulating Area5150

Posted on 2023-06-03, 01:07

I've tried it on two machines around here... one is a desktop Core i7 860 with a GeForce 970. The other is a laptop Core i7 2720QM with an nVidia NVS4200M. But that makes me wonder: do you use the GPU for more than just trivial rendering of framebuffers generated by the emulator on the CPU? The GPU …

Re: Emulating Area5150

Posted on 2023-06-01, 00:16

I've made an initial Windows release of my emulator, available here: https://github.com/dbalsom/martypc/releases/ Interested to see what people think. I'm open to suggestions and feature requests!

Re: CGA Cursor Hiding

Posted on 2023-05-31, 13:41

sigh. I had a stupid bug in masking off the attribute bits, so I didn't see both the BIOS and CGA_COMP were in fact setting bits 5&6 to 01. No use in having debug displays if they feed you bad information...

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