groepaz wrote: ↑Fri Jan 10, 2020 4:28 pm
so how will you load your suggested format into vic20 memory without additional loader? yeah sure, you could have specific hardware to like you suggest - however without such extra hardware you need a loader that puts the data where it belongs. and with the extra hardware you will have to know how to setup the hardware before loading. and thats a terrible idea for emulator - for emulation the fileformat should provide all info that is needed to run the cartridge.
In the C64 .CRT files, you have codes telling the emulator what to do, what type of cartridge image you're dealing with and there is software components in VICE (or even an Easy Flash cart or 1541 Ultimate cart) that recognize these codes and process the information accordingly.
You are correct in indicating the old unified format was originally intended for RAM expansions with specific hardware added, a very simple one.
But the file format itself acts the same way the codes of a C64 .CRT do. They can tell an emulator or cartridge replicator what to do.
1. It's really a .PRG file with a very specific subset of characteristics. They only load at $2000 or $4000 and they can only be 16386, 8194 or 4098 bytes in size. If they load at $4000 and contain the A0CBM immediately after the loading address then the content of BLK2 should be transferred to BLK5. If they load at $2000 and contain the A0CBM signature at byte 8194 then the content of BLK2 should be transferred to BLK5. The last case is if they load at $4000 but contain no A0CBM signature then they are Scott Adams games.
AFAIK, the above information is as clear as the information codes found in C64 .CRT files.
2. If you don't have the original hardware, you can still load them on most VIC-20s having 16k or more of added RAM. If you load the file to it's intended address and find the A0CBM signature at $4000, transfer the content of BLK2 into BLK5
Code: Select all
FORT=16384TO23575:POKE T+24576,PEEK(T):NEXT
Then turn your expansion to read-only (most 32k-37k expansions have a switch for that nowadays) then SYS64802 (then SYS32592 if you're running a Scott Adams game)
Every idea is bad if you don't bother making sense of it.
and some ideas are just bad.
To prejudiced people, every idea is bad and everyone is wrong no matter how good they may really be.
Be normal.