Unfortunately notCan the value of the memory at PC be used?
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- Fri Oct 06, 2023 8:38 am
- Forum: Emulation and Cross Development
- Topic: Stack Watching in VICE
- Replies: 21
- Views: 5638
Re: Stack Watching in VICE
- Fri Oct 06, 2023 7:28 am
- Forum: Emulation and Cross Development
- Topic: Stack Watching in VICE
- Replies: 21
- Views: 5638
Re: Stack Watching in VICE
I don't think this can be done directly (please correct me if i am missing something) - you can only compare registers and memory locations, there is no way to tell "was pulled from stack". Perhaps you can do something like ($100+SP)=$55 && A=$55 (which is obviously not really what...
- Mon Oct 02, 2023 5:21 am
- Forum: Programming
- Topic: C=Hacking Issue 8 - fast plot routine with 20 cycles
- Replies: 7
- Views: 2280
Re: C=Hacking Issue 8 - fast plot routine with 20 cycles
Next step would be unrolling the loop for each needed slope... perhaps not on VIC20 though
- Fri Sep 22, 2023 3:27 pm
- Forum: Games
- Topic: Crazy Cavey
- Replies: 11
- Views: 3758
Re: Crazy Cavey
Raster tricks are actually easier than on VICII - since there are no "bad lines". Very straight forward
- Fri Sep 22, 2023 2:35 pm
- Forum: Hardware and Tech
- Topic: Making a cheap Power supply.
- Replies: 5
- Views: 3116
Re: Making a cheap Power supply.
I don't think you'll fry something - but it will not work
- Wed Sep 13, 2023 12:08 pm
- Forum: Hardware and Tech
- Topic: I/O0 and illegal opcodes
- Replies: 9
- Views: 3579
Re: I/O0 and illegal opcodes
All the modern loaders doAlso I know the C64-fastloader Spindle uses illegals to do GCR-decoding on the fly which was deemed impossible before.
- Wed Sep 13, 2023 9:53 am
- Forum: Hardware and Tech
- Topic: I/O0 and illegal opcodes
- Replies: 9
- Views: 3579
Re: I/O0 and illegal opcodes
but there does exist software that uses the so-called "illegal opcodes". To add to this: not seldom in old games there are undocumented opcodes executed not because the coder used them intentionally, but because they are a result of accidental memory corruption during development. (This i...
- Sun Sep 10, 2023 11:22 am
- Forum: Other Systems
- Topic: New Release: PETSTRIP for PET/CBM 3032 and 4032
- Replies: 5
- Views: 3079
Re: New Release: PETSTRIP for PET/CBM 3032 and 4032
This is really very cool. Imagine showing this to ppl back in 1980 :=)
- Sun Jul 02, 2023 5:22 pm
- Forum: Programming
- Topic: Need help converting multicolor font from atari to commodore.
- Replies: 1
- Views: 1107
Re: Need help converting multicolor font from atari to commodore.
As said on Lemon - can't you simply use it as is? The binary format should be the same
- Sun Jul 02, 2023 5:37 am
- Forum: Other Systems
- Topic: Help modifying C64 PAL code for NTSC machine
- Replies: 5
- Views: 3231
Re: Help modifying C64 PAL code for NTSC machine
It uses PB7 indeed, and that's L - correct
The problem might indeed be the video source - if the video was deinterlaced, ie is now 25fps, then it will probably not work
The problem might indeed be the video source - if the video was deinterlaced, ie is now 25fps, then it will probably not work
- Sat Jul 01, 2023 7:23 am
- Forum: Other Systems
- Topic: Help modifying C64 PAL code for NTSC machine
- Replies: 5
- Views: 3231
Re: Help modifying C64 PAL code for NTSC machine
Generally on NTSC everything needs to be 20% percent faster (50Hz PAL vs 60Hz NTSC). So, when you you look at the code, there is one delay loop at $c044 which is called with different values in X at various places. So the first/easy attempt is to make this delay loop 20% faster (which then means all...
- Fri Jun 30, 2023 6:49 pm
- Forum: Other Systems
- Topic: Help modifying C64 PAL code for NTSC machine
- Replies: 5
- Views: 3231
Re: Help modifying C64 PAL code for NTSC machine
this is the code to begin with .C:c000 A5 2B LDA $2B .C:c002 85 FC STA $FC .C:c004 A5 2C LDA $2C .C:c006 85 FD STA $FD .C:c008 A9 00 LDA #$00 .C:c00a 8D 03 DD STA $DD03 .C:c00d 20 E4 FF JSR $FFE4 ; check keyboard .C:c010 C9 00 CMP #$00 .C:c012 F0 F9 BEQ $C00D .C:c014 20 4D C0 JSR $C04D .C:c017 20 75...
- Wed Jun 28, 2023 10:33 am
- Forum: Programming
- Topic: Vic-20 mouse driver & demo program for NEOS mouse
- Replies: 54
- Views: 31290
Re: Vic-20 mouse driver & demo program for NEOS mouse
I think you'll have to make sure to plug in the mouse before turning on the computer, and also make sure nothing else uses that joystickport before you run the NEOS program.... its really all a bit unstable
- Sat Jun 17, 2023 8:50 am
- Forum: Hardware and Tech
- Topic: Can you use a 6502B clocked at 1Mhz in a Vic20?
- Replies: 4
- Views: 3347
Re: Can you use a 6502B clocked at 1Mhz in a Vic20?
Its just the maximum clock rating, many MOS chips have this. In a VIC20 (or C64 for that matter) any "A" or "B" (and variants without) can be used
- Sat Jun 17, 2023 8:48 am
- Forum: Programming
- Topic: Loading multiple data files into memory - HELP!!!
- Replies: 8
- Views: 1004
Re: Loading multiple data files into memory - HELP!!!
If you are using kernal, you can use one file and patch into the STOP vector (iirc) to update the progress bar (or do whatever during load)