Search found 180 matches

by Wilson
Mon Mar 11, 2024 12:42 pm
Forum: Emulation and Cross Development
Topic: Assembler
Replies: 36
Views: 1460

Re: Assembler

Most concepts of assembly transfer from computer-to-computer. If you understand the fundamentals, it's easy to apply them to any given system. But the 6502 is as good a place to start as any, and Jim Butterfield's "Machine Language for the Commodore 64 and other Commodore Computers" is pro...
by Wilson
Tue Jan 30, 2024 8:40 pm
Forum: Programming
Topic: MONster 6502 full IDE and Debugger on FE3
Replies: 1
Views: 346

Re: MONster 6502 full IDE and Debugger on FE3

Aha, I've been found! :mrgreen: Yes, this has been a "little" project of mine for quite a while. The veritable embodiment of scope creep. As its name implies, this project originated as a symbolic monitor, then a TASM (or VASM) like editor/assembler. The RAM requirements kept growing, and ...
by Wilson
Mon Nov 06, 2023 7:47 pm
Forum: Programming
Topic: VIC 20 Graphics Artist
Replies: 29
Views: 6705

Re: VIC 20 Graphics Artist

This is incredibly cool stuff.
Thanks for sharing and welcome to the forum, Neil!
by Wilson
Wed Nov 01, 2023 5:25 pm
Forum: Hardware and Tech
Topic: PCB manufacture
Replies: 2
Views: 2351

Re: PCB manufacture

These two are pretty popular:
https://jlcpcb.com/
https://oshpark.com/
by Wilson
Thu Oct 19, 2023 9:59 am
Forum: Emulation and Cross Development
Topic: VICE key-rollover inconsistencies
Replies: 3
Views: 2063

Re: VICE key-rollover inconsistencies

Ah, very good. Thanks for the validation! Yeah, my immediate thought was that the OS and/or input device were to blame, but the VICE status bar gave me some assurance that every relevant key event was reaching the emulator correctly in at least these simple test cases. I definitely believe it's a co...
by Wilson
Thu Oct 19, 2023 5:26 am
Forum: Emulation and Cross Development
Topic: VICE key-rollover inconsistencies
Replies: 3
Views: 2063

VICE key-rollover inconsistencies

Hey all, I haven't dug too deep into this, but has anyone encountered any quirks with the the handling of key-rollover in the Vic-20 emulation in VICE? The C64 keyboard emulation seems to handle these cases. For context, I was adapting the routine described here although, from some further testing, ...
by Wilson
Sun Oct 08, 2023 7:57 am
Forum: Hardware and Tech
Topic: New penultimate-plus-2-cartridge
Replies: 57
Views: 11528

Re: New penultimate-plus-2-cartridge

Definitely sounds like a bug, Rich. I couldn't find the source for this cartridge, but it seems like the browser is skipping over the (17*n)th file/directory for some reason. Maybe the file offset is incrementing to 17 (because of a general cursor down handler for example), where the next file would...
by Wilson
Sat Oct 07, 2023 2:04 pm
Forum: Emulation and Cross Development
Topic: Stack Watching in VICE
Replies: 21
Views: 4186

Re: Stack Watching in VICE

chysn, does your assembler JSR to the PC instead of RTI'ing to it as Mike said? I guess based on your question regarding RTS behavior that your assembler returns to the monitor in such a scenario? I've been working on my own assembler and went with the push PC, P, Y, X, A, RTI approach as well. Some...
by Wilson
Thu Oct 05, 2023 10:18 am
Forum: Programming
Topic: Assembly: Detect when result rolls over from 255 to 0
Replies: 6
Views: 2210

Re: Assembly: Detect when result rolls over from 255 to 0

CODE: SELECT ALL ldy #8 @@ lda src,y sta dest,y dey bpl @@ Although 9/10 times this will be ldy #8-1 :) That or @@ lda src-1,y sta dest-1,y dey bne @@ Which has the benefit of allowing iteration for .Y values of [$80, $100). Of course, this only works with non-indirect addressing.
by Wilson
Mon Oct 02, 2023 7:21 pm
Forum: Hardware and Tech
Topic: 40- and 80-column expansions
Replies: 7
Views: 2286

Re: 40- and 80-column expansions

Are you aware of these two? CBM Command (looks like this is someone else's clone of the repo? Sadly, I think Payton left the community and deleted everything he could after growing frustrated with some members of the community). DIRPlus I think they both use 22-columns (or thereabout) and I'm not su...
by Wilson
Mon Oct 02, 2023 6:43 am
Forum: Hardware and Tech
Topic: 40- and 80-column expansions
Replies: 7
Views: 2286

Re: 40- and 80-column expansions

Mike wrote: Mon Oct 02, 2023 12:57 am IMO, users would be better off using one of the bigger 8-bit CBMs instead, or a C128.
Agreed! The VIC chip is the soul of the computer IMO (it's even in the name ha). Take away the VIC-20's video hardware, and you're left with a pretty generic 8-bit computer.
by Wilson
Fri Sep 29, 2023 7:28 pm
Forum: Programming
Topic: Zero Page addressing and BASIC
Replies: 3
Views: 1826

Re: Zero Page addressing and BASIC

The "bank" behavior you're referring to is a feature of the 6510. There are no software considerations needed on the plain 6502 for the $00-$01 addresses. Some (most even) of the zero-page is used by the KERNAL and BASIC. A lot of it can nonetheless be used if you know what you're doing an...
by Wilson
Fri Sep 29, 2023 8:03 am
Forum: Games
Topic: Midnight Crimes
Replies: 7
Views: 2924

Re: Midnight Crimes

Wow, this is really cool! :D Well done!
by Wilson
Thu Sep 14, 2023 1:28 pm
Forum: Hardware and Tech
Topic: I/O0 and illegal opcodes
Replies: 9
Views: 2632

Re: I/O0 and illegal opcodes

That's a fair question, and I've thought about it a lot in the course of my assembler design. I think that code is about communication with people as well as machines, so it's totally with that aesthetic in mind. Meaning is better conveyed by this: Huh, never thought of it in terms of disassembly e...
by Wilson
Thu Sep 14, 2023 9:07 am
Forum: Hardware and Tech
Topic: I/O0 and illegal opcodes
Replies: 9
Views: 2632

Re: I/O0 and illegal opcodes

I often use the multi-byte illegal NOPs, TOP ($3c, a.k.a. SKW) and DOP ($34, a.k.a. SKB) as selectors, because they're terribly useful: It's a very common pattern, but, out of curiosity, why not just use the BIT opcodes ($24 and $2C)? The Vic-20 KERNAL (and many other 6502 programs) do this. The on...