Denial

Hi, Dave, first of all, welcome to Denial! :) I see you tried to adapt my View3K program for the use with a +3K RAM expansion. View3K had been written with the tight space available on a unexpanded VIC-20 in mind, consequently it goes through quite some hoops, which are not necessary with extra RAM ...

i have found a lot of nice stuff from Toby Lobster. [...] The algorithm as given by Mr. Lobster very much agrees with what I did, taking the 2nd order conic equation for the ellipse and deriving the difference equations for stepping along the ellipse perimeter. You can either try to port over those...

Source: thread " Kleine OS-Knobelei " in Forum64. Caution should be taken when using JSR $D08B (see also " ROM calls and other tricks "). Its expected function is to scan the tokenized BASIC text for a variable name, allocate that variable if it does not exist yet and finally, re...

Please use in VICE the aspect ratio of 0.5. Please note the non-square aspect ratio of the pixels can be handled purely by software , and there is no good reason at all to demand people de-adjust their monitor settings! The reference is the pixel aspect ratio on a TV set calibrated with a broadcast...

The VIC-6560 data sheet states an Input Clock Cycle Time of 69.84 ns maximum and 69.82 ns minimum, which correspond to frequencies of 14.318 MHz and 14.323 MHz, respectively. The figure you give, 14.342 MHz, is already out of spec for VIC-I, neither is there any guarantee it will work with any displ...

Standalone VIC-20 pixel art got announced/posted here in the General section mostly, " Ghostship " and " Jalapeno " being recent examples that come to my mind. So, for the moment, standalone graphics/pixel art, demos and music can well be placed in the General section. If the aut...

[...] this one runs only on actual Vic 20 [...] You can always run the tool in emulation. At one point you will anyhow be concerned about data transfer between your cross development setup hosted on PC, and the target platform, regardless whether the latter is emulated or on real hardware. There is...

[...] I am trying to work with screen memory at location $200, to be able to use screen bitmapping (in this way I have the entire ram area between $1000 to $1fff for characters). I can set it correctly [...] As the two posters before me already had pointed out, the code you show here has several is...

Hi, and welcome to Denial, I also have one of the SD card floppy style sd2iec devices that I use with a fast loader on the C64. Can this also be used on the VIC-20 and if so what links are available on how to setup the SD card to load the menu etc? all the SD2IEC devices work quite the same way on t...

My bad, I stand corrected.

Of course there's no need to place the screen into internal RAM, for VIC-I, when there's another video chip which has its own RAM elsewhere.

BASIC reports [...] As soon as BLK1 is populated with RAM, the range for the +3K RAM expansion is blocked from BASIC use. As maximum value, BASIC reports 28159 bytes free *). There is a sticky Memory Map in the Programming Section, please consult such info beforehand. *) unless, for example, the VF...

For what matters, the VIC-20 User Guide already contains the two tables of PETSCII and screen codes in its appendices. This code is rather confusing as it swaps between screen codes and PETSCII. The two contain (mostly) the same symbols, which means it's easy to get muddled. I am surprised the diagn...

In CBM DOS, only 254 bytes of a block are used for data. The first two bytes of each block either contain the sector link or the 'last block' tag together with the number of valid bytes in that sector. What actually gets transmitted to the computer are the load address and the actual file data, 4097...

For everyone who is interested to take a peek at the "Ghostship" picture within Picasso, I have converted the *.prg file back to Picasso format. The picture consists of two files, "0GHOSTSHIP" and "1GHOSTSHIP", which contain the bitmap plus VIC register dump, and the co...

You could perhaps consider a smaller number of chars used for the bitmap by arranging the chars in a circular fashion? Rotating vector objects tend to fill a circular area. I suppose the use case is a cockpit view of a space ship , where there is not a single (rotated) vector object, but multiple, ...