Search found 16 matches
- Sun Feb 03, 2013 6:36 am
- Forum: Buy, Sell, and Trade
- Topic: *SOLD OUT* 32k RAM expansions for the VIC-20 - 25$ each
- Replies: 60
- Views: 12181
- Wed Jan 30, 2013 12:08 pm
- Forum: Buy, Sell, and Trade
- Topic: *SOLD OUT* 32k RAM expansions for the VIC-20 - 25$ each
- Replies: 60
- Views: 12181
- Wed Jan 30, 2013 12:04 pm
- Forum: Programming
- Topic: Smooth vertical scrolling problem...
- Replies: 4
- Views: 3704
I stumbled across it just by playing with a program to test screen sizes, allowing me to control width, height, x position, y position.. I simply noticed that when HPOS was 0 the screen moved by one single raster line from the set VPOS value of 2 line resolution, and a spark ignited :) I haven't fou...
- Sun Jan 27, 2013 4:32 am
- Forum: Programming
- Topic: Smooth vertical scrolling problem...
- Replies: 4
- Views: 3704
Smooth vertical scrolling problem...
I'm trying to setup a vertical scrolling screen, but smoothly using HPOS==0 to delay the screen by the extra line to get single line position.. This works fine, and very well.. On top of that, I also want to blank the top of the display to hide the offscreen region so it scroll on smoothly without h...
- Sat Aug 25, 2012 1:58 pm
- Forum: General Topics
- Topic: USB download options ?
- Replies: 5
- Views: 1045
- Sat Aug 25, 2012 12:08 pm
- Forum: General Topics
- Topic: USB download options ?
- Replies: 5
- Views: 1045
- Sat Aug 25, 2012 10:43 am
- Forum: General Topics
- Topic: USB download options ?
- Replies: 5
- Views: 1045
USB download options ?
Whilst busy canning my retro bug I discovered I couldn't come to be parted from my VIC's, which inspired going back to basics and re-discovering why the VIC made me fall in love with it, from a programming point of view and game-play point of view also.. That aside.. Are there any options on the mar...
- Thu Mar 15, 2012 2:33 am
- Forum: Programming
- Topic: Pulse Sounds..
- Replies: 8
- Views: 2316
Erm, it's not clear is it, but I didn't have the memory for a fancy CPU load like the 64 version.. The multicoloured bit is just a fixed loop (of ~10000 cycles) run from a per frame interrupt.. It's there to show how much variance there is from the interrupts running in the background, hence why it ...
- Wed Mar 14, 2012 11:07 am
- Forum: Programming
- Topic: Pulse Sounds..
- Replies: 8
- Views: 2316
Well the whole thing was initially just an idea of a way to synthesis some additional voices without the normal massive cpu-overhead required.. To test it out, rather than writing a full blown music driver in parallel, I simply grabbed so NES NSF music files, and then wrote a later to convert the 3 ...
- Tue Mar 13, 2012 4:27 am
- Forum: Programming
- Topic: Pulse Sounds..
- Replies: 8
- Views: 2316
Pulse Sounds..
Well, actually more about synthesising lots of software voices, but with little CPU overhead, well much less than traditional means, and the bonus is the voices are playing back at 15.6K.. Really :) It's an idea from a long time ago, and after a few silly ideas ideas ended up with something useful.....
- Tue Jan 17, 2012 7:32 am
- Forum: Programming
- Topic: Sid Vicious - VIC 20 SID emulation
- Replies: 65
- Views: 35778
- Mon Jan 16, 2012 7:55 am
- Forum: Programming
- Topic: Sid Vicious - VIC 20 SID emulation
- Replies: 65
- Views: 35778
just noticed you're talking about the specific LAX #immediate addressing mode - this IS flakey on most 6502s and generally not included in lists of LAX addressing mode documentation. So the question flips around - what's the board and CPU of the 128 where it DOES work? ;) I've no idea :) It's merel...
- Sun Jan 15, 2012 5:36 am
- Forum: Programming
- Topic: Sid Vicious - VIC 20 SID emulation
- Replies: 65
- Views: 35778
Um, look at that: ;----- table of selfmod locations selfmodloc: .byte o1add_,o1addh_,o1wav_,o1pw_,o1ple_,o1phe_,o1lev_ .byte o2add_,o2addh_,o2wav_,o2pw_,o2ple_,o2phe_,o2lev_ .byte o3add_,o3addh_,o3wav_,o3pw_,o3ple_,o3phe_,o3lev_ So unless you are prepared to change the way ALL of these switches wor...
- Sun Jan 15, 2012 4:32 am
- Forum: Programming
- Topic: Sid Vicious - VIC 20 SID emulation
- Replies: 65
- Views: 35778
It's rather massively self modifying really, but I think there's enough cycles to be saved that you could pull it out of the ZP without losing any speed with enough thinking.. Just looking quickly, looks like you can save 3 bytes on the ;- oscillator switch o1wav_: jmp o1off since this is always pre...
- Fri Jan 13, 2012 8:58 am
- Forum: Programming
- Topic: Sid Vicious - VIC 20 SID emulation
- Replies: 65
- Views: 35778