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  1. VileR

    Area 5150 for IBM PC 4.77MHz

    The rotating 3D object scene has a couple of IRQ handlers where long sequences of NOPs are used to fine-tune the timing of certain critical code. That's probably why it glitches on a V30 or on a faster 8088 (and in emulators).
  2. VileR

    Area 5150 for IBM PC 4.77MHz

    For me it was mostly fasm on my modern desktop, then PCem for quick testing (as far as my own parts of the code are concerned it mostly does the trick), then onto the CF card and into the 5160. For troubleshooting I mainly relied on the internal DOSBox debugger - display rendering may be way...
  3. VileR

    Area 5150 for IBM PC 4.77MHz

    Most parts are expected to run well enough on clones, but sections like the end credits are more sensitive to inaccuracies than anything in 8088 MPH was. Some later clones (chiefly ones based on custom chipsets) are already known to have issues. Compaq's are some of the most compatible out...
  4. VileR

    Area 5150 for IBM PC 4.77MHz

    Some good news on the non-IBM front. Area 5150 runs correctly on a Compaq Portable all the way through: (ignore the TV).
  5. VileR

    Area 5150 for IBM PC 4.77MHz

    Glad you liked it! Ha- never heard of that game until now, but apparently there's a 'Super Life of Pixel' now which includes a "CGA"-styled world...
  6. VileR

    Area 5150 for IBM PC 4.77MHz

    The per-frame code really doesn't take all that much CPU time - IIRC no more than ~20% in this version ("profiled" using border-color changes). Should be plenty left for game logic, but the real problem would be all the writing to video RAM, which has to fit in vertical blanking for a...
  7. VileR

    Area 5150 for IBM PC 4.77MHz

    Yes, that's "ansi-from-hell" at 80x100 characters. That's why the tiles weren't simply converted from the arcade version (they had to be redrawn for optimal use of the fixed CGA charset). Are you saying you see visual glitches when Prohibition/Boulder Dash scroll sideways? I don't remember...
  8. VileR

    Area 5150 for IBM PC 4.77MHz

    No, but perhaps it can help indirectly if your board and drivers let you use it as UMBs (or even just the page frame window) to free up more conventional RAM... I've seen reports about that being possible on a PC/XT. Supporting EMS directly would be cumbersome and probably not as effective as...
  9. VileR

    Area 5150 for IBM PC 4.77MHz

    We do want to shrink that RAM footprint somewhat - there's quite a bit of flexibility as to when we can load and unload various bits of code, thanks to Trixter's loader system. Currently it requires about 560-570kB free, and that can be improved. 512kB systems are going to be difficult to...
  10. VileR

    Area 5150 for IBM PC 4.77MHz

    Yes, please watch the second video linked by reenigne in post #4. The one in the OP was taken from the video shown at the party - we had to make that one on location using mobile capture equipment, so it has some issues and isn't 100% representative. The basic tricks for achieving 16 colors in...
  11. VileR

    Converting a PC Booter Game to Cassette Tape

    Didn't they have that "manufacturing test" device mentioned in the BIOS listing, which loaded custom code through the keyboard port during POST? I can remember at least one commercial IBM PC game (Avalon Hill's Galaxy?) which was sold on disk, but had the option of saving to/loading from...
  12. VileR

    CGA 160x100x16 bidirectional scrolling

    The 8088 only gets a small fraction of the total frame time to push all this data out, if you want to avoid display issues. That's a limitation of CGA architecture in this particular mode. I don't think the Amstrad CPC or Gameboy have similar constraints (could be wrong of course). The 'safe'...
  13. VileR

    Portuguese characters in brazilian hardware

    Ah, ok. Something about that name "Updating" didn't immediately suggest that it referred to the vendor ;) The "MCGP" on the sticker seems to be a pretty generic acronym for Monochrome/Color Graphics/Printer. So with that "M" plus the existence of a crystal, and four(!) jumpers, I'd be...
  14. VileR

    Portuguese characters in brazilian hardware

    Hey, welcome to VCF! Being a PC bitmap font junkie, this is some very useful data right there - appreciate the historical notes too... those dumps would fit right in in my quest for international charsets for the Oldschool PC font pack. What's "updating.bin" though? :) that one seems to contain...
  15. VileR

    1983 - coming ready or not

    Yes, my impression is that it really does depend. It's not that you *must* start with assembly language, but I don't see why the idea is so questionable. And whatever Microsoft did in the 1980s, it's saner than the way they developed Altair BASIC through BASIC-86 on emulators of Intel CPUs...
  16. VileR

    1983 - coming ready or not

    Self-hosting compilers aren't that unusual. Typically I guess you'd start developing the compiler in another language, say assembly, and once you have the capability to compile at least some C code, you can start replacing bits of the source with your version of C until you've got something...
  17. VileR

    CGA 160x100x16 bidirectional scrolling

    As far as I know, it's possible to latch a new counter value so the PIT doesn't load it until the current one hits zero. But this only works if: * You're using timer mode 2 or 3, and * You write your value without sending a new command byte first. Unless both of the above are true, the new...
  18. VileR

    CGA 160x100x16 bidirectional scrolling

    Hm, come to think of it, I remember seeing something weird with PCem's PIC implementation. I could be wrong, but my suspicion was it failed to set the correct bit to indicate that a given IRQ is in service. *If* that's the problem, and another IRQ is firing while your interrupt handler is...
  19. VileR

    CGA 160x100x16 bidirectional scrolling

    Very nicely done! Gave it a go on my 5160 with an IBM CGA card and there's zero snow during the actual game. (It snows during the black screen just before the game starts, but at least that can be easily hidden by blanking out the video.) Curiously, in PCem I do see the snow... it starts about...
  20. VileR

    Two EGA monitors, color pallette is different

    The Goldstar one sorta looks like a problem in the signal path. Maybe with Secondary Green (pin 6), since the 2 colors in your photo which have that bit set look bright pink. But it's hard to tell without seeing all 16 default colors together.
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