Search found 4665 matches
- Sun Feb 11, 2024 5:07 am
- Forum: Emulation and Cross Development
- Topic: Corrupt end of basic program
- Replies: 7
- Views: 274
Re: Corrupt end of basic program
Hi, I only use VICE. It happens 10% of the savings, and mostly at the end of the disk-directory or at the end of the tape. I made backups. I made a backup of this program with this error and didn't touch it after that. The backup is fine, curious. Other strange thing: I make backups of the floppies....
- Sat Feb 10, 2024 6:36 pm
- Forum: Emulation and Cross Development
- Topic: Corrupt end of basic program
- Replies: 7
- Views: 274
Re: Corrupt end of basic program
What tool did you use to create the program file in first place? This error is typical for a BASIC program file that for whatever reason was saved with a missing last byte . By itself, the SAVE command of BASIC does not produce that problem - but once a BASIC program is loaded that has been produced...
- Sat Feb 10, 2024 6:26 am
- Forum: Programming
- Topic: "Ultimate Expansion" - new firmware for FE3
- Replies: 59
- Views: 9934
Re: "Ultimate Expansion" - new firmware for FE3
This.srowe wrote:I guess [the RTC is] used to set the timestamps of files written to the SD card.
Unfortunately, many other (commercially available) SD2IEC drives economize on this aspect.
- Sat Feb 10, 2024 6:20 am
- Forum: Programming
- Topic: Recommendations for VIC-20 assembly tutorial, tools
- Replies: 10
- Views: 694
Re: Recommendations for VIC-20 assembly tutorial, tools
To be specific, I have a copy of some VIC 20 Diagnostic firmware that has a bug when it comes to determining how to display on the screen (I get odd colors). Are you sure this is not due to a hardware bug (faulty colour RAM, for example) in your VIC-20 itself? In that case it would be a waste of ti...
- Sat Feb 10, 2024 5:42 am
- Forum: Programming
- Topic: Line drawing algorithm
- Replies: 20
- Views: 1193
Re: Line drawing algorithm
I was able to get it down to under 15 cycles per pixel on average? That would imply your routine accesses/modifies each involved bitmap byte only once, i.e.: having LDA - ORA/EOR/AND #imm - STA present and inlined for all 36 possible horizontal line segments, removing all further address arithmetic...
- Sat Feb 10, 2024 5:11 am
- Forum: Hardware and Tech
- Topic: Another ram expansion? Yes it is
- Replies: 25
- Views: 4209
Re: Another ram expansion? Yes it is
Mike sum[s] up the challenge with adding memory visible to the VIC chip, but, I made a prototype circuit that will fix this problem. Just for the record, I solved said "challenge" or "problem" years ago already with aforementioned VFLI mod, by installing the RAMx range memory on...
- Sat Feb 10, 2024 2:45 am
- Forum: Programming
- Topic: Need help with adding custom character set
- Replies: 6
- Views: 199
Re: Need help with adding custom character set
How can I make sure the font file has the proper load address? The load procedure with SYS57809 ... SYS65493 that I highlighted above forcibly loads the font file to $1400, yet still a load address needs to be present as first 2 bytes of the file (making it 2050 bytes total). I have checked the fil...
- Sat Feb 10, 2024 2:17 am
- Forum: Programming
- Topic: Need help with adding custom character set
- Replies: 6
- Views: 199
Re: Need help with adding custom character set
You normally would not want to do that as then the text screen and character set are at the same position.ricky_derocher wrote:What would be the poke(s) needed to set the font for $1000?
The first usable position for the font then is at $1400, see my edited post above for more details.
- Sat Feb 10, 2024 1:45 am
- Forum: Programming
- Topic: Need help with adding custom character set
- Replies: 6
- Views: 199
Re: Need help with adding custom character set
Just "bload" the font 9 block font file into place, and then POKE the right address to change to the font. That works quite the same on the VIC-20. VIC register 36869 sets the character generator base address (bottom 4 bits) and the screen start (top 4 bits, together with the top bit of 3...
- Thu Feb 08, 2024 1:06 pm
- Forum: Hardware and Tech
- Topic: Another ram expansion? Yes it is
- Replies: 25
- Views: 4209
Re: Another ram expansion? Yes it is
I [...] saw your vfli mod, what you did there is superb, so you place 3k on the VIC side with hw mod. Is it possible to add more ram this way, i mean, can we add other blocks on the VIC side too? I know it is not much meaningful since VIC can utilize 4k but the display area could have been switched...
- Thu Feb 08, 2024 9:34 am
- Forum: Hardware and Tech
- Topic: Another ram expansion? Yes it is
- Replies: 25
- Views: 4209
Re: Another ram expansion? Yes it is
Is there a way to address this problem with this memory expansion? No. See here: https://sleepingelephant.com/ipw-web/bulletin/bb/viewtopic.php?t=10385&start=7&hilit=CPU+VIC+side , and to quote from there: The 6502 in the VIC-20 cannot tri-state its address bus, therefore the address (and d...
- Tue Feb 06, 2024 3:47 am
- Forum: Programming
- Topic: Resetting IRQs
- Replies: 10
- Views: 349
Re: Resetting IRQs
Those 2 IRQs are not used for IO? The two VIA #2 timers control the timing of either the KERNAL IRQ (keyboard, jiffy clock, tape motor control) or the timing of tape load (T1 only) and save (T1 and T2). The VIA #1 timers produce NMIs (mostly for RS232 operations). It is somewhat possible to run sta...
- Mon Feb 05, 2024 4:30 pm
- Forum: Programming
- Topic: Resetting IRQs
- Replies: 10
- Views: 349
Re: Resetting IRQs
;save the registers ldx #31 @ lda $9110,x sta $b9e0,x dex bpl @- That idiom isn't all that helpful to restore the state of the VIAs later - some of the registers (most notably the IER!) react differently to writes than to reads. Instead I'd simply do a SEI , then clear both IERs with LDA #$7F:STA $...
- Mon Feb 05, 2024 1:06 pm
- Forum: Other Systems
- Topic: Extremely Rare Ala Software game for C64 - Whiz Kid
- Replies: 12
- Views: 696
Re: Extremely Rare Ala Software game for C64 - Whiz Kid
Thank you for dumping the tape, however as this is a C64 title it might be of minor interest in the VIC-20 Denial Games section. [...] if anybody has a means to convert it to a D64 file, that would be awesome. You should perhaps place that inquiry in one of the more numerous C64 forums instead. (mod...
- Mon Feb 05, 2024 6:19 am
- Forum: Programming
- Topic: Starting VIC-20 unexpanded-project UEFA European football championship 2024
- Replies: 5
- Views: 401
Re: Starting VIC-20 unexpanded-project UEFA European football championship 2024
Loading longer programs from another program. [...] At the beginning of the program the locations 45,46,47,48,49,50 must be set with the correct values. [...] Calculate the space you need, calculate the address where the space must start. These are the memory-locations that must be filled with the ...