Log inRegister an accountBrowse CSDbHelp & documentationFacts & StatisticsThe forumsAvailable RSS-feeds on CSDbSupport CSDb Commodore 64 Scene Database
You are not logged in - nap
CSDb User Forums


Forums > C64 Coding > $d011 trickery – duplicated text lines
2011-04-29 21:39
Digger

Registered: Mar 2005
Posts: 448
$d011 trickery – duplicated text lines

Does any one know the $d011 trick to repeat the first char row? I am trying to cancel badlines on the 8th line of each charline (between cycles 54-57) but it doesn't work. The first line gets duplicated but only twice.
 
... 57 posts hidden. Click here to view all posts....
 
2021-11-23 11:08
Rastah Bar
Account closed

Registered: Oct 2012
Posts: 336
What do real C64s show in bitmap mode?

This link shows a Vice 3.5 x64sc screenshot:
https://postimg.cc/62qvYV86

and this a Vice 3.1 x64 screenshot:
https://postimg.cc/z3Vkjf75

So, probably there is a bug also in bitmap mode.
2021-11-27 20:46
PiCiJi

Registered: Oct 2021
Posts: 2
Quote: Ticket submitted, feel free to edit if you think it isn't explained clearly or if something is missing.

https://sourceforge.net/p/vice-emu/bugs/1627/


I added a patch with some explanation.
2021-11-27 20:59
tlr

Registered: Sep 2003
Posts: 1814
Quote: I added a patch with some explanation.

Good find!

Will test this for corner cases.
2021-11-27 22:37
JackAsser

Registered: Jun 2002
Posts: 2038
How on earth did VICE implenent it in the first place?! All adresses should be derived from ONE pointer (VCBASE). Will inspect the patch, curious!
2021-11-27 23:56
tlr

Registered: Sep 2003
Posts: 1814
Quote: How on earth did VICE implenent it in the first place?! All adresses should be derived from ONE pointer (VCBASE). Will inspect the patch, curious!

It's related to the char and color buffer in the VIC, not VCBASE. There was a race between writing (vmli) and reading this out (dmli) in an apparently rare case.
2021-11-28 00:08
JackAsser

Registered: Jun 2002
Posts: 2038
Quote: It's related to the char and color buffer in the VIC, not VCBASE. There was a race between writing (vmli) and reading this out (dmli) in an apparently rare case.

Ahh yes ofc, I see.
2021-11-28 00:56
Krill

Registered: Apr 2002
Posts: 3098
Quoting tlr
It's related to the char and color buffer in the VIC, not VCBASE. There was a race between writing (vmli) and reading this out (dmli) in an apparently rare case.
But can this be exploited for demo purposes? :)
2021-11-28 12:15
tlr

Registered: Sep 2003
Posts: 1814
Quote: Quoting tlr
It's related to the char and color buffer in the VIC, not VCBASE. There was a race between writing (vmli) and reading this out (dmli) in an apparently rare case.
But can this be exploited for demo purposes? :)


Probably not, but never say never.

I'm not even sure these counters are separate counters in reality.
It was a long time since I wrote that piece of code, but I think part of the choice was due to trying to separate the cpu clock domain code from the dot clock domain code more cleanly.
2022-03-20 14:21
tlr

Registered: Sep 2003
Posts: 1814
I've committed a fix for the bug 1627 issue in r41978 (based on the patch PiCiJi supplied).

This should really be emulated in the way described here: bug 218, but not today. :)

The committed fix passes the regression suite (thanks gpz!) but please test the current trunk with your "worst" VIC-II abuse!

Builds are here: https://github.com/VICE-Team/svn-mirror/releases
2022-03-25 08:57
tlr

Registered: Sep 2003
Posts: 1814
friendly reminder: Please run some of your tests this weekend.
Previous - 1 | 2 | 3 | 4 | 5 | 6 | 7 - Next
RefreshSubscribe to this thread:

You need to be logged in to post in the forum.

Search the forum:
Search   for   in  
All times are CET.
Search CSDb
Advanced
Users Online
Jasmin68k
Didi/Laxity
Rik
Guests online: 363
Top Demos
1 Next Level  (9.7)
2 13:37  (9.7)
3 Codeboys & Endians  (9.7)
4 Mojo  (9.6)
5 Coma Light 13  (9.6)
6 Edge of Disgrace  (9.6)
7 Signal Carnival  (9.6)
8 Wonderland XIV  (9.5)
9 Uncensored  (9.5)
10 Comaland 100%  (9.5)
Top onefile Demos
1 Nine  (9.7)
2 Layers  (9.6)
3 Cubic Dream  (9.6)
4 Party Elk 2  (9.6)
5 Copper Booze  (9.5)
6 Scan and Spin  (9.5)
7 Onscreen 5k  (9.5)
8 Grey  (9.5)
9 Dawnfall V1.1  (9.5)
10 Rainbow Connection  (9.5)
Top Groups
1 Artline Designs  (9.3)
2 Booze Design  (9.3)
3 Oxyron  (9.3)
4 Performers  (9.3)
5 Censor Design  (9.3)
Top Graphicians
1 Mirage  (9.7)
2 Archmage  (9.7)
3 Sulevi  (9.6)
4 Pal  (9.6)
5 Hein  (9.6)

Home - Disclaimer
Copyright © No Name 2001-2025
Page generated in: 0.119 sec.