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Sheddy

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Sheddy last won the day on July 5 2011

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About Sheddy

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    Dragonstomper

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    Male
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    UK
  • Interests
    Retrogaming, Atari 8-bit/2600/5200 Development

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  1. Thanks all. Plenty of ideas there to try and to learn about. Much appreciated.
  2. Yep ATR is a good container. If I could just use exe/xex on its own though I wouldn't need to write any loading code at all and leave it to the binary loader
  3. I think you're right Rybags about work variables judging by my initial failed experiments with trying to use just NOTE with DOS 2.5 during its binary loader as suggested by dmsc. It's a simple PC utility I'm making to create the disk/exe slides so I may just stick to plain disk sectors and no DOS to save added complexity in it writing to a DOS ATR. As a key feature of the utility is to be able to extract the original picture XEXs again I think portability to other DOSes may be less of an issue. I was ideally hoping to not rely on any particular DOS at all and just be able to distribute XEX and rely on fundamental binary loader functionality common to them all. So, for example, just drag and drop XEX onto Altirra and instant slide show. But the lack of being able to implement a loop function that way, (which I believe most people would think is an essential feature for what has to be a pretty small slideshow), is a literal show stopper (Terrible pun).
  4. Thanks guys, that is all very insightful. I would be looking for maximum portability. I guess some modern device handlers/emulators binary load might just "magically" inject exe segments into memory too. I had read that NOTE only worked in update mode too in OS manual. That'd be a great trick though. The mini DOSes would be a natural for something like a slideshow to squeeze in as many slides as possible, so may have to rule that out. Ironically I had started out using ATR and switched to XEX thinking it'd be more portable. Problem then becomes what to do with larger than standard 90/120K disk. Do we just start using 256 byte sectors for bigger?
  5. So, I'm trying to create a slide show exe which will loop back once the last slide is done. With a standard exe we can chain load and show pictures with init. However once at the end of the file, is there a safe way to set things back to start over at the beginning of the file that will work with all binary loaders from different DOSes? I assume the exe will not know how it has been called or what its file name is. I'm pretty clueless about doing things with DOS and couldn't see an obvious way to do this, so hope this is a simple thing. Thanks.
  6. Space Harrier doesn't do both sample and screen changes every scan line, you probably would need some kind of screen kernel for that, rather than interrupts. SH Source.zip
  7. There is some middle ground between basics and "assumed already expert" that something like this with practical examples can fill nicely. Seems like a great idea. EG on disk handler sector read, what kind of status should we expect. If it fails should we try again, or assume bad sector. On topic of exact cycle wasting I nominate clockslide https://www.pagetable.com/?p=669as one of the sneakiest tricks. Not something that instantly springs to mind! cmp (0,x) 6 cycle wait in 2 bytes if you don't mind messing up the carry
  8. Have updated the first post with the .bin version to save stripping off the .car header
  9. That one makes sense - it's so 128 is the exact centre of the screen.
  10. I don't think mads is the right thing for what you want unless I'm misunderstanding. Get and put are done at assembly time, not runtime? Something like the exomizer compressor might be worth looking at. There is a level compressor which can stream to a circular buffer, although the example decrunch code is not up to date and it looks quite daunting to me.
  11. opt h- f+ org $2000 .byte 1,2,3 .align $7f,0 .byte $ff 01 02 03 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 FF only 64? change to ".align $7e,0" 01 02 03 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 FF ?
  12. Not really, does same as .cb "Hello" no good for screen display unless custom charset
  13. Yep, thanks. looks like I'll have to be doing that. On another note, is .align supposed to work to exact bytes rather than just pages? Not that it turns out to be that useful for padding out to 128 byte sectors, but when I was experimenting it seems to behave peculiarity with things like ".align $7f"?
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