Denial

Is there a way to address this problem with this memory expansion? No. See here: https://sleepingelephant.com/ipw-web/bulletin/bb/viewtopic.php?t=10385&start=7&hilit=CPU+VIC+side , and to quote from there: The 6502 in the VIC-20 cannot tri-state its address bus, therefore the address (and d...

Those 2 IRQs are not used for IO? The two VIA #2 timers control the timing of either the KERNAL IRQ (keyboard, jiffy clock, tape motor control) or the timing of tape load (T1 only) and save (T1 and T2). The VIA #1 timers produce NMIs (mostly for RS232 operations). It is somewhat possible to run sta...

;save the registers ldx #31 @ lda $9110,x sta $b9e0,x dex bpl @- That idiom isn't all that helpful to restore the state of the VIAs later - some of the registers (most notably the IER!) react differently to writes than to reads. Instead I'd simply do a SEI , then clear both IERs with LDA #$7F:STA $...

Thank you for dumping the tape, however as this is a C64 title it might be of minor interest in the VIC-20 Denial Games section. [...] if anybody has a means to convert it to a D64 file, that would be awesome. You should perhaps place that inquiry in one of the more numerous C64 forums instead. (mod...

Loading longer programs from another program. [...] At the beginning of the program the locations 45,46,47,48,49,50 must be set with the correct values. [...] Calculate the space you need, calculate the address where the space must start. These are the memory-locations that must be filled with the ...

Perhaps an incomplete, multicolor-only MG mode would be still easy to add - and very useful for VIC 20 people... Multipaint saves also to some native formats, so it could have an option to save MG picture file. You could then do some hires edits/additions in Minipaint on VIC. Put the other way roun...

I am very well aware of that. :wink: Note though even for half axes 'just' in the range 0..255, the values in the work variables E, F, G, S, T, U and V can become rather large and need 32-bit registers to store them correctly. CBM BASIC can represent these numbers within its floating point format wi...

SparkyNZ, you try to draw conclusions from the document that are not in any way backed by what is actually the case: So working with a PAL monitor, I guess the maximum display resolution for any (non-VIC) signal would be 704×576? The TV norms as such do not define any horizontal resolution in pixels...

Having mixed hires&multi characters in picture as in MG may be more tricky, as I don't know if any of the graphic modes in Multipaint currently support this (I didn't peek in the code, but this could be a design limitation in the editor, due to its multi-format nature) I had a short exchange wi...

I bet this is a question for Mike. I just happen to be the first one to answer this time, but there are also other candidates. What is the maximum number of pixels the Vic chip can display on a TV screen - this is including moving the screen from top-leftmost to bottom-rightmost? I guess you are as...

Hi, Aleksi, Please send Dr. Terrorz a spec of MG format [...] (email at bottom of page [...]) thank you for the hint, I've sent a corresponding e-mail asking for the inclusion of the MG file format. [...] an executable viewer [...] One of the niceties of these files is they already come with a built...

Is anyone able to identify this Vic20 screen editor? As groepaz already has pointed out, this screenshot is from Multipaint. Unfortunately, Aleksi Eeben did not do the graphicians on the VIC-20 a favour when suggesting to the maker of Multipaint that it should adapt the 176x176 (hires) pixel screen...

First of all, it's not the VIC-20 that switches between PAL and SECAM, it's your display which mistakes the video signal of your VIC-20 for SECAM for some of the time. Real SECAM output requires an adapter PCB in the VIC-20. Do you own a contemporary, "non-intelligent" CRT monitor to cross...

i have the FE3 as an .prg file from the BADAPPLE demo with rev020. Please note that the Bad Apple demo comes with an own dedicated firmware for FE3: to play on VICE emulator, first add fe3badas7.5.prg as a Final Expansion cartridge. Then attach badrom7.5.d64 as a 1541 disk image. This firmware dump...

I have some source code that I would like to examine to see if I can find a bug(s) that is present (I didn't write the code). That is a somewhat strange motivation to start out with 6502 machine language, but then so be it. You might want to take a look at my VICMON primer . Only requirements are t...