José Pereira Posted July 14, 2014 Share Posted July 14, 2014 Using just one charset for all the screen in a static multi-screens 5colours ANTIC4 no PFs DLIs game and because of that last/240th scanline bug is it possible to place the chars on all the 30charlines? No problem with cpu because there's only 2 or 3 little sprites moving horizontally and and not much more just the PMGs... And the PAL (312scanlines) and NTSC (262scanlines) any difference? I tested the static screen on PAL Altirra and it shows all with the cpu is always between 55% and 62%. Is this right? Quote Link to comment Share on other sites More sharing options...
Heaven/TQA Posted July 14, 2014 Share Posted July 14, 2014 in my "40x40" texmode using VSCROL trick is actually a "40x39"... as far as I know... 30 lines are not possible... with 8 scanline chars. Quote Link to comment Share on other sites More sharing options...
Rybags Posted July 14, 2014 Share Posted July 14, 2014 Antic 4 30 lines is no problem. Scanline 240 bug only occurs on the hires modes and even then it can be overcome with a bit of programming. CPU time - yes, with 6 extra text lines there'll be less available. Throw in H-Scrolling and it'll drop even more. Quote Link to comment Share on other sites More sharing options...
José Pereira Posted July 14, 2014 Author Share Posted July 14, 2014 So to me there's no problem? Thanks Rybags because I thought the bug was in all modes and now I know it isn't. And 240scanlines in these case can work in PAL and NTSC with no problem? Quote Link to comment Share on other sites More sharing options...
popmilo Posted July 14, 2014 Share Posted July 14, 2014 30 is kinda too much imho... 28 chars are around millimeter from top and bottom edge of my TV Quote Link to comment Share on other sites More sharing options...
Heaven/TQA Posted July 14, 2014 Share Posted July 14, 2014 oh... then 40x40 in my case I did something wrong @Jose where did you check the CPU usage? Quote Link to comment Share on other sites More sharing options...
José Pereira Posted July 14, 2014 Author Share Posted July 14, 2014 oh... then 40x40 in my case I did something wrong @Jose where did you check the CPU usage? Out now but I checked it in Altirra in top of the window if you enable to show the cpu % and the fps. Quote Link to comment Share on other sites More sharing options...
Heaven/TQA Posted July 14, 2014 Share Posted July 14, 2014 isnt that the CPU usage of your PC running the emulator and not the 6502 CPU usage? Or did I get you wrong? Quote Link to comment Share on other sites More sharing options...
Rybags Posted July 14, 2014 Share Posted July 14, 2014 That show CPU% doesn't relate to the Atari - it's just saying how much of the PCs CPU the emulation is using. You can't really easily meter the 6502 - it has no wait instruction, it's always "busy" - about all you could do to calculate idle time is to have a profiling system that knows which blocks of code in the OS are wait loops. 1 Quote Link to comment Share on other sites More sharing options...
Heaven/TQA Posted July 14, 2014 Share Posted July 14, 2014 Check out... http://a8.fandal.cz/detail.php?files_id=7026 just found it as new release... this one has 30 lines Antic 4. 1 Quote Link to comment Share on other sites More sharing options...
Xuel Posted July 14, 2014 Share Posted July 14, 2014 Altirra's profiling features can give you a good estimate of how much the CPU is throttled by a graphics mode. Just enter an infinite loop and look at the DMA% column: 1) Select Debug -> Profile -> Profile View 2) Click on Play button with Instruction Sampling mode selected (LDA) 3) Press Stop button after a couple seconds and now the Profile View is populated with the instruction samples with the most executed instructions on top 4) You can double click on the instruction to see a disassembled Source View. You must have a VBI routine to restore DLISTL/H every frame, but that's negligible. So, the conclusion here is that a 30 row ANTIC 4 mode throttles the CPU down to 62.3% of it's maximum. Although, even with no display the RAM refresh cycles consume 7.9% of the available cycles, so really the 30-row ANTIC 4 mode leaves around 67% of the actual base number of available CPU cycles. For comparison, a 24 row ANTIC 4 mode screen throttles the CPU to 74% of it's actual maximum. So you're only loosing around 9.5% more cycles, i.e. (74-67)/74. Source code and executable: tallscreen.zip 2 Quote Link to comment Share on other sites More sharing options...
Xuel Posted July 14, 2014 Share Posted July 14, 2014 Numbers for NTSC: Base: 92.1% 24-row: 69% (of 92.1%) 30-row: 61.3% (of 92.1%) Delta: 11.1% fewer cycles 1 Quote Link to comment Share on other sites More sharing options...
+Stephen Posted July 14, 2014 Share Posted July 14, 2014 The endless possibilities of the Altirra debugger (and someone with brains enough to use it ) Quote Link to comment Share on other sites More sharing options...
Xuel Posted July 15, 2014 Share Posted July 15, 2014 I wrote a short script to calculate the percentage CPU time available for each ANTIC mode at varying heights. See github. 5 Quote Link to comment Share on other sites More sharing options...
dmsc Posted July 15, 2014 Share Posted July 15, 2014 I wrote a short script to calculate the percentage CPU time available for each ANTIC mode at varying heights. See github. Useful script! I would add the first blank modelines (3 standard) and the last jump (another 3 cycles) to the DMA cycles. Quote Link to comment Share on other sites More sharing options...
Xuel Posted July 15, 2014 Share Posted July 15, 2014 I would add the first blank modelines (3 standard) and the last jump (another 3 cycles) to the DMA cycles. Good point! I've updated the script and tables on github. Thanks! 1 Quote Link to comment Share on other sites More sharing options...
Heaven/TQA Posted July 15, 2014 Share Posted July 15, 2014 Xuel... good stuff... and I love Altirra Debugger... Quote Link to comment Share on other sites More sharing options...
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