Search found 4685 matches
- Mon Apr 22, 2024 8:48 am
- Forum: Emulation and Cross Development
- Topic: ASM502 - a new 6502 assembler.. (WIP)
- Replies: 22
- Views: 4223
Re: ASM502 - a new 6502 assembler.. (WIP)
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...
- Mon Apr 22, 2024 2:09 am
- Forum: Programming
- Topic: Sprites in ML
- Replies: 55
- Views: 26099
Re: Sprites in ML
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...
- Sun Apr 21, 2024 2:39 am
- Forum: Programming
- Topic: Unexpanded VIC Font Editor
- Replies: 4
- Views: 1303
Re: Unexpanded VIC Font Editor
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...
- Sat Apr 20, 2024 10:39 am
- Forum: Programming
- Topic: Sprites in ML
- Replies: 55
- Views: 26099
Re: Sprites in ML
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...
- Sat Apr 20, 2024 7:51 am
- Forum: Hardware and Tech
- Topic: Cart Expander connector spacing?
- Replies: 5
- Views: 2502
Re: Cart Expander connector spacing?
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...
- Sat Apr 20, 2024 5:31 am
- Forum: Programming
- Topic: Unexpanded VIC Font Editor
- Replies: 4
- Views: 1303
Re: Unexpanded VIC Font Editor
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...
- Fri Apr 19, 2024 10:50 am
- Forum: Hardware and Tech
- Topic: WIP: VIC-2020 MINIMON cartridge
- Replies: 54
- Views: 18754
Re: WIP: VIC-2020 MINIMON cartridge
To all concerned:
MINIMON has been released on sourceforge, under the CC-BY-SA 4.0 licence.
Greetings,
Michael
MINIMON has been released on sourceforge, under the CC-BY-SA 4.0 licence.
Greetings,
Michael
- Thu Apr 18, 2024 1:18 am
- Forum: Emulation and Cross Development
- Topic: ASM502 - a new 6502 assembler.. (WIP)
- Replies: 22
- Views: 4223
Re: ASM502 - a new 6502 assembler.. (WIP)
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...
- Tue Apr 09, 2024 11:45 am
- Forum: Hardware and Tech
- Topic: Run/Stop Restore doesn't work
- Replies: 3
- Views: 1207
Re: Run/Stop Restore doesn't work
[...] The IER does not work like a classical read/write register. Actually, the MSB specifies an action (0 = reset bit(s), 1 = set bit(s)), the lower 7 bits specify which of the interrupt sources is affected. More details here: Stop a running timer - and further discussion about the half dozen meth...
- Tue Apr 09, 2024 4:04 am
- Forum: Hardware and Tech
- Topic: Run/Stop Restore doesn't work
- Replies: 3
- Views: 1207
Re: Run/Stop Restore doesn't work
The order is important here: to initiate the BASIC warmstart, the STOP key must be held down while the RESTORE key is tapped. The other way round the NMI routine in the KERNAL will return immediately and pressing the STOP afterwards then has no effect. Does the STOP key function on its own (i.e. can...
- Mon Apr 08, 2024 7:54 pm
- Forum: Collecting and History
- Topic: 2024 eBay pricing, What the actual?
- Replies: 4
- Views: 1325
Re: 2024 eBay pricing, What the actual?
Wouldn't this rely on an FPGA implementation of the VIC chip? That's a common misconception. As I wrote elsewhere : a complete emulation of a computer, be it a software-only as in VICE or as combination of hardware and software in a FPGA has substantially relaxed timing requirements, as ultimately ...
- Mon Apr 08, 2024 6:44 pm
- Forum: Games
- Topic: Pixel's Harvester and a corrupt wetware memory.
- Replies: 4
- Views: 1361
Re: Pixel's Harvester and a corrupt wetware memory.
[...] colour clash. It's what the Speccy is famous for, but it didn't do it first. The Vic-20 beat it to colour-clash by at least a year. [...] About any home computer at that time had to compromise on memory bandwidth for the video chip. Adding lower resolution attributes to the 'B/W' display data...
- Mon Apr 08, 2024 2:25 am
- Forum: Programming
- Topic: Double buffering screen bitmap
- Replies: 22
- Views: 8557
Re: Double buffering screen bitmap
In "Back in the Good Old Days" demo from 2004 I allocated chars dynamically (like a ring buffer) when drawing and eor-filling the frame [...] Char 0 was used for empty screen [...] I had 3 more "preset" chars for quickly filling 4x16 pix areas of solid colors (bit patterns $55, ...
- Sun Apr 07, 2024 4:15 am
- Forum: Collecting and History
- Topic: 2024 eBay pricing, What the actual?
- Replies: 4
- Views: 1325
Re: 2024 eBay pricing, What the actual?
There seems to be an odd contradiction, as more people find Dad's box of computer stuff in the loft and flog it there are more people wanting to reminisce about their first computer. Or the sellers simply count on uninformed buyers. For example, nearly all cartridges had their ROMs being dumped so ...
- Sat Apr 06, 2024 6:57 am
- Forum: General Topics
- Topic: ** Revision 2024 Invitation / Website
- Replies: 18
- Views: 4441
Re: ** Revision 2024 Invitation / Website
I struggled with those double irqs If the purpose of those "double IRQs" is to set up a stable raster IRQ, you might want to take a sharp look at this: ** Stable rasters on the VIC-20 . That is the canonical way to do this on the VIC-20, with a cycle exact timer interrupt once per frame, ...