Denial

The ROM table at $EDE4 can be used to obtain useful default values for XPOS and YPOS by applying constant offsets , regardless whether you have a PAL or NTSC VIC-20: $EDE4 contains 12 for PAL and 5 for NTSC, when you substract 5, you get 7 for PAL and 0 for NTSC. $EDE5 contains 38 for PAL and 25 for...

How does the Vic-20 know which block is available? The VIC-20 does not "know" this - the mainboard logic tries to access memory at some address regardless whether that memory is present or not. I think if the EPROM chip is not enabled by the expansion port then the data pins on the EPROM ...

Interpreted BASIC on the VIC-20 is too slow by about two orders of magnitude to make this effect viable. No amount of trying to optimize the BASIC code is going to change that, even in the presence of a BASIC extension like MINIGRAFIK that at least gives a headache-free access to bitmap graphics. As...

I also didn't know how I'd solve the problem of drawing and moving so many bubbles around at the time while keeping in one screen refresh (50 fps) or at worst two (25 fps). On the C64, only Bub, Bob and the enemies are done with sprites, at full frame rate. The bubbles are not animated with anythin...

It is so slow. :shock: It isn't fast on the C64 either. The article in C=Hacking recommends using a SuperCPU. Does anyone have an idea how to speed this up in BASIC? Simplify the arithmetic stuff as much as possible. Factor out repeated calculations out of the main loop that yield the same value du...

[...] who wants to invest months in a game for nothing in return[?] It is somewhat unfair to come up with this argument to someone who first of all just asked about a possible port of BB to the VIC-20. One still finds companies that sell commercial game software for the VIC-20, so there must be a m...

Hi, scalz8! First of all, welcome to Denial! :mrgreen: I just made a quick peek at your WIP or demonstrator. For ease of discussion, here's the program text: 10 PRINT:PRINT:PRINT:PRINT:PRINT:PRINT:PRINT:PRINT:PRINT:PRINT:PRINT:PRINT 11 PRINT:PRINT:PRINT:PRINT:PRINT:PRINT:PRINT:PRINT:PRINT:PRINT:PRIN...

I did start thinking in terms of pattern recognition within the intemediate code, so for example [...] Except it does not show the character set but merely clears the screen, that one in a post of mine dating from 2016 is actually the same example as yours: If you take the simple assignment stateme...

The data of the sprite is not correct. With VIC register $9005 set to 240, the only thing the VIC-I chip does is - displaying the ROM character set. If i change the register $9005 from $F0 (240) to $FE (254) the start text cannot be seen. As @thegg already wrote, you need to supply a copy of the RO...

Ah, I get your temporary unexpand comment... Probably not. yeah -- since the video memory map is identical, LOAD... 8,1 is necessary then SYS manually instead of RUN. The tool I linked to, "3K.PRG", temporarily 'unexpands' the VIC-20. It sets the BASIC limits and the screen position as fo...

I don't get the change between Poke 36869,240 and Poke36869,254 displayed correctly. Can someone here perhaps provide support? Judging by the disassembly, all the code ever does is writing $F0 to VIC register $900F, during init. If $900F was supposed to be changed to another value than $F0, the cor...

I'd recommend just passing [pins 20 and Y] through exactly like all other lines. There exist cartridges which misuse either pins 20 or Y on their edge connectors to simplify routing. If one cartridge connects 20 or Y to +5 V and one other cartridge connects the same pin to GND you short the power s...

I made a thing started from scratch Sunday. [...] Nice! It's an interesting idea to move up the BASIC start to $1800, so the character set sits comfortably at $1000. You might consider adding a raster split in the middle of the screen, between UI and font display, so the UI can still use the standa...

To all concerned:

MINIMON has been released on sourceforge, under the CC-BY-SA 4.0 licence.

Greetings,

Michael

orac81 was more cautious in the response, but anyway: During assembly, keep a hold of the state of the machine and comment on instructions that do not affect that state. For example: if it can be known that the carry is set, then do not assemble a SEC, but comment in the listing that that instructio...