Search found 4640 matches

by Mike
Mon Mar 18, 2024 3:56 am
Forum: General Topics
Topic: modded VIC 20 kernals?
Replies: 12
Views: 405

Re: modded VIC 20 kernals?

[...] asking for the screen size returns hard coded values. It would have been nice if that was dynamic, but sadly too late. The KERNAL call JSR $FFED (SCREEN) is beyond uselessness. It assumes a level of abstraction (regarding the screen size) that at that time neither was expected nor required fr...
by Mike
Sat Mar 16, 2024 2:51 pm
Forum: Programming
Topic: Line drawing algorithm
Replies: 15
Views: 703

Re: Line drawing algorithm

MrSterlingBS wrote:[...]
PM sent
by Mike
Sat Mar 16, 2024 4:59 am
Forum: Programming
Topic: Line drawing algorithm
Replies: 15
Views: 703

Re: Line drawing algorithm

Here's my take on this subject: Before any questions come up in this regard: MINIGRAFIK already contains a line routine, which is not as fast as the routine below, however it is much more compact (just about 100 bytes extra beyond the pixel set function otherwise already provided within the MG code)...
by Mike
Sat Mar 16, 2024 3:47 am
Forum: General Topics
Topic: modded VIC 20 kernals?
Replies: 12
Views: 405

Re: modded VIC 20 kernals?

The KERNAL is accessed through a jump table in RAM. You can change those jump points and switch out any KERNAL subroutine you want without having to replace ROMs. That is the same case with the C64, but it did not give people a reason not to produce modified KERNAL ROMs. Edit/Addition : That being ...
by Mike
Thu Mar 14, 2024 1:16 pm
Forum: Programming
Topic: A sample programming session in VICMON
Replies: 32
Views: 16270

Re: A sample programming session in VICMON

[...] why use [SBC]? If you do the sign inversion in the same context as done in BALLPING (i.e. a given zero page address as source and target), for both methods you'll arrive at (DX := $F9): ; ** using SBC: SEC LDA #$00 SBC $F9 STA $F9 7 bytes, 10 cycles ; ** using EOR #$FF and 2s-complement: CLC ...
by Mike
Thu Mar 14, 2024 3:22 am
Forum: Programming
Topic: A sample programming session in VICMON
Replies: 32
Views: 16270

Re: A sample programming session in VICMON

Merytsetesh wrote:To get DX = -DX, why not XOR with 128 instead of using SBC?
That would only be correct with sign-magnitude representation.
by Mike
Wed Mar 13, 2024 11:07 am
Forum: Programming
Topic: MINIGRAFIK lineart
Replies: 47
Views: 16740

Re: MINIGRAFIK lineart

allenhuffman wrote:I am trying to find why I was quoted here? I don’t see a post?
That's Denial's way of notifying someone about a post that might be of his or her interest. :mrgreen:
by Mike
Sun Mar 10, 2024 5:16 am
Forum: Programming
Topic: MINIGRAFIK lineart
Replies: 47
Views: 16740

Re: MINIGRAFIK lineart

Here's another port of Super Expander lineart to MINIGRAFIK ( download ); this time, 's Kangaroo duo Lionel and Joey: https://dateipfa.de/.Public/denial/images/minigrafik/kangaroo.png As with Garfield earlier in this thread, the drawing is primarily made from circle/ellipse arcs and lines. The MG im...
by Mike
Sun Mar 10, 2024 4:02 am
Forum: Programming
Topic: How do I redefine characters with 8k or more RAM?
Replies: 25
Views: 3248

Re: How do I redefine characters with 8k or more RAM?

I didn't understand that there was math involved in creating that number. When you did not ask about that detail, it was foreseeable to me that you would run into this issue: next logical step after redefining part of a character set would be redefining the entire character set. I did not want to l...
by Mike
Fri Mar 08, 2024 12:30 pm
Forum: Emulation and Cross Development
Topic: Assembler
Replies: 24
Views: 1002

Re: Assembler

Merytsetesh wrote:I do wish the VIC had an inline assembler.
wAx2? :wink:
by Mike
Fri Mar 08, 2024 9:59 am
Forum: Emulation and Cross Development
Topic: Assembler
Replies: 24
Views: 1002

Re: Assembler

groepaz wrote:use whatever the people you can ask use.
+1
by Mike
Fri Mar 08, 2024 2:37 am
Forum: Emulation and Cross Development
Topic: Assembler
Replies: 24
Views: 1002

Re: Assembler

As you had some exposure to the Acorn Archimedes series, and if you're adventurous, you might consider using the inline assembler of BBC BASIC, the one contained in HI BASIC (part of the !65tube emulation) in particular. :mrgreen: Otherwise, quite some people here use either dasm or ACME , so there ...
by Mike
Fri Mar 08, 2024 2:11 am
Forum: Hardware and Tech
Topic: What do I need for a NTSC to PAL conversion on a short board?
Replies: 1
Views: 288

Re: What do I need for a NTSC to PAL conversion on a short board?

You might want to take a look at this thread: VIC20 NTSC > PAL Conversion.

The OP links to a document on zimmers.net: PAL VIC20 Goes NTSC (just backwards).
by Mike
Fri Mar 08, 2024 2:03 am
Forum: Emulation and Cross Development
Topic: Reverse Engineering of JETPAC for VIC-20
Replies: 12
Views: 1337

Re: Reverse Engineering of JETPAC for VIC-20

Mike wrote:[T]hat clearly positions this thread into the "Emulation & Cross-Development" section, as it concerns the use of tools that don't run on the VIC-20 itself.
done
by Mike
Tue Mar 05, 2024 6:00 am
Forum: General Topics
Topic: ** Revision 2024 Invitation / Website
Replies: 4
Views: 874

Re: ** Revision 2024 Invitation / Website

The video of the invitation intro is online on YT: https://www.youtube.com/watch?v=fdB3Ell9F1M

Enjoy! :mrgreen: