Denial

You can save some cycles in the column renderer if you replace "bit 0" with "cmp #0" or some other immediate instruction. "bit 0; bit 0" can be replaced with "jmp *+4; nop". There are some other easy savings possible with undocumented opcodes if you are willin...

Question: where exactly are the accumulator, X, and Y variables stores in the VICs memory? Accumulator is 780 ($30C) X register is 781 ($30D) Y register is 782 ($30E) Processor status is 783 ($30F) Those apply only for BASIC. When you do SYS, those values are copied to CPU registers. After the rout...

VIC-1525, the friendly printer by the looks of the box

I bought my VIC-1020 when the local store got rid of their VIC-20 inventory. I think I paid 50 FIM for it, about 8.50 euros. I also bought lots of cartridges for 9 FIM (1.50€) each.

wimoos wrote:

Code: Select all

	LDY $64 ; high byte
...
	DEY

Just "DEC $64", it's not siginificantly slower and saves one byte

OT: DTL Jetpack BASIC compiler for C64 has its own garbage collector which uses RAM below IO/kernal for temporary buffer, speeding up the process a lot as it can defragment string area in 12 KB chunks.

Omega Race & Planetfall

Pedro Lambrini wrote:Yes, but nobody else has access to that (yet!).

Here...

orion70 wrote:infocom
Infocom's text adventures.

Kananga wrote:Is there really a program for the Vic-20 that needs 35K RAM?

Yes. My Infocom interpreter.

You can use any ZP locations, even $FF/$00 pair. You just have to take care that you don't mess any kernal/BASIC pointers you might need later. $FB-$FE are used in examples because they aren't used for anything by the system.

See this thread.

You can only reliably decode 2 keys pressed at once. Any more than that and the result is ambiguous because you create unintended pathways through the matrix. I wonder how much accurate is the VICE emulator in this regard. Emulated result depends on the keyboard as well as the emulator. Some el che...

infocom Infocom's text adventures. Nice. The parser isn't finished yet tho. It might be, one day. Awww, come on. Do we need to make this a Kickstarter-project? :wink: It looks like it's 90% done - or what is still missing? Save & restore are missing, otherwise the V3 parser is complete & bu...

orion70 wrote:infocom
Infocom's text adventures.

Nice. The parser isn't finished yet tho. It might be, one day.

Look at the size of that thing!

Somewhat shorter link: http://www.ebay.co.uk/itm/271016328949


VIC 20 looks really nice!

How about using the 65C02 code but starting with "bit lwctr"