Search found 180 matches
- Mon Mar 11, 2024 12:42 pm
- Forum: Emulation and Cross Development
- Topic: Assembler
- Replies: 38
- Views: 6906
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...
- Tue Jan 30, 2024 8:40 pm
- Forum: Programming
- Topic: MONster 6502 full IDE and Debugger on FE3
- Replies: 1
- Views: 1562
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 ...
- Mon Nov 06, 2023 7:47 pm
- Forum: Programming
- Topic: VIC 20 Graphics Artist
- Replies: 29
- Views: 8839
Re: VIC 20 Graphics Artist
This is incredibly cool stuff.
Thanks for sharing and welcome to the forum, Neil!
Thanks for sharing and welcome to the forum, Neil!
- Wed Nov 01, 2023 5:25 pm
- Forum: Hardware and Tech
- Topic: PCB manufacture
- Replies: 2
- Views: 3528
- Thu Oct 19, 2023 9:59 am
- Forum: Emulation and Cross Development
- Topic: VICE key-rollover inconsistencies
- Replies: 3
- Views: 3286
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...
- Thu Oct 19, 2023 5:26 am
- Forum: Emulation and Cross Development
- Topic: VICE key-rollover inconsistencies
- Replies: 3
- Views: 3286
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, ...
- Sun Oct 08, 2023 7:57 am
- Forum: Hardware and Tech
- Topic: New penultimate-plus-2-cartridge
- Replies: 57
- Views: 15347
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...
- Sat Oct 07, 2023 2:04 pm
- Forum: Emulation and Cross Development
- Topic: Stack Watching in VICE
- Replies: 21
- Views: 6121
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...
- Thu Oct 05, 2023 10:18 am
- Forum: Programming
- Topic: Assembly: Detect when result rolls over from 255 to 0
- Replies: 6
- Views: 2251
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.
- Mon Oct 02, 2023 7:21 pm
- Forum: Hardware and Tech
- Topic: 40- and 80-column expansions
- Replies: 7
- Views: 3534
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...
- Mon Oct 02, 2023 6:43 am
- Forum: Hardware and Tech
- Topic: 40- and 80-column expansions
- Replies: 7
- Views: 3534
- Fri Sep 29, 2023 7:28 pm
- Forum: Programming
- Topic: Zero Page addressing and BASIC
- Replies: 3
- Views: 1919
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...
- Fri Sep 29, 2023 8:03 am
- Forum: Games
- Topic: Midnight Crimes
- Replies: 7
- Views: 4391
Re: Midnight Crimes
Wow, this is really cool! Well done!
- Thu Sep 14, 2023 1:28 pm
- Forum: Hardware and Tech
- Topic: I/O0 and illegal opcodes
- Replies: 9
- Views: 3895
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...
- Thu Sep 14, 2023 9:07 am
- Forum: Hardware and Tech
- Topic: I/O0 and illegal opcodes
- Replies: 9
- Views: 3895
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...