Heaven/TQA Posted April 20, 2008 Author Share Posted April 20, 2008 another advantage to use your own irq loader... in conjunction with an own nmi service routine you can leave OS and have nearly full ram for your code... Quote Link to comment Share on other sites More sharing options...
Heaven/TQA Posted April 20, 2008 Author Share Posted April 20, 2008 (edited) ok.ok... a dream of mine comes true... i always loved the Atari ST "now loading"-big scroller of the game Enchanted Land which appeared while loading... so... here is the work of 2 hours of throwing IRQ loader plus rewritten PM-scroller together... same procedere... boot the pmscroll2.atr, when flashing insert empty.atr and press start... now again the 132 sector data will be loaded but with the bouncing pm scroller on top of it... (the scroller was coded 1996... ) the scroller can be run in VBL but when using in conjunction with the OS disk routines, no way... atari stops his work...now check out pmscroll1.atr which uses not a VBL but a main loop instead and the OS disc routines... let it run and you know that this is not good as well... just to show you that the IRQ loader discussion here is not wasted time... irq2.zip Edited April 20, 2008 by Heaven/TQA Quote Link to comment Share on other sites More sharing options...
miker Posted April 20, 2008 Share Posted April 20, 2008 Welll... maybe it's fascinating but nowadays it's slight use for it. Especially when more and more people usie several kinds of harddisk controllers which are not using standars SIO commands but their own instead. So, maybe just give up this project or at least make some alternative to or not to use that digi-sound during loading. Quote Link to comment Share on other sites More sharing options...
Heaven/TQA Posted April 20, 2008 Author Share Posted April 20, 2008 Miker... as more I get into C64 coding the more I am going back to the roots... and tend to the rule 800 XL+1050... maybe 130xe optional... 1 Pokey and that's it... no additional hardware, nor harddiscs... pure 1984 setup... ok. got the point with todays harddiscs but I have sio2usb so I will check how this simple demos work when run from sio2usb plus flashcard... Quote Link to comment Share on other sites More sharing options...
analmux Posted April 20, 2008 Share Posted April 20, 2008 Heaven, I still don't really see why it wouldn't be possible to do VBI and IRQ together. Quote Link to comment Share on other sites More sharing options...
Heaven/TQA Posted April 21, 2008 Author Share Posted April 21, 2008 Analogue, I just pointed out that including the scroller into an VBI (as in general you would) plus doing diskio (os routines) it won't work right now as the scroller needs too much time. I haven't ment IRQ+VBI. Simply what a newbie would do.... trying to run a VBL with fx while loading...that's what i tried in 1996 and realised that not possible with stuff built in. Quote Link to comment Share on other sites More sharing options...
Rybags Posted April 21, 2008 Share Posted April 21, 2008 A couple of solutions: 1. Do the scroller in the deferred VBlank. Advantage is that IRQs are enabled so risk of serial overrun is reduced. Disadvantage there is that it's skipped if an IRQ was being serviced when VBI occurs. So, probably a bad solution. 2. Use the same trick the OS uses, in your Imm VB routine. It checks the P status on the stack - if IRQs were enabled when VBI occurs, that means that the VBI didn't interrupt an IRQ in service. You can then enable IRQs to allow the SIO to work normally. The problem with both methods is that on the odd occasion, the VBlank interrupts when an IRQ is half way through being serviced. In such cases, you can't re-enable IRQs as it might cause a double-trigger event ( = bad ). And, the double-whammy is that if the VB routine just goes on, you risk serial overrun. A possible workaround might be to have a DLI routine which is selectively enabled to do the work of your VBI in such cases that the VBlank occurs during an IRQ service. Quote Link to comment Share on other sites More sharing options...
dwhyte Posted April 21, 2008 Share Posted April 21, 2008 Whew... so much to digest... Quote Link to comment Share on other sites More sharing options...
+Stephen Posted April 23, 2008 Share Posted April 23, 2008 Heaven, are these PAL only? They don't work on my NTSC 130XE. Stephen Anderson Quote Link to comment Share on other sites More sharing options...
Heaven/TQA Posted April 23, 2008 Author Share Posted April 23, 2008 oh. interesting... the irq loader does not get to the "wait til start" at the beginning... will double check that... Quote Link to comment Share on other sites More sharing options...
emkay Posted April 23, 2008 Share Posted April 23, 2008 Miker... as more I get into C64 coding the more I am going back to the roots... and tend to the rule 800 XL+1050... maybe 130xe optional... 1 Pokey and that's it... no additional hardware, nor harddiscs... pure 1984 setup... That's the right way. Otherwise we could take a Mini ITX and put it into an 800 Case and show how powerful the A8 can be by playing something like Doom on it ... It's the same thing with my Hardsynth demonstrations. OK, the last ones were stereo, but only for proving the manifold of sounds that can be put out of the POKEY. With a sampled 3rd voice like it is done "last time" we could stick again on the real thing . Later we gonna patch games like Warhawk (particular the Extirpator) with real cool sounding music Quote Link to comment Share on other sites More sharing options...
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