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Forums > C64 Coding > How to disable default charsets in bank 0 and 2
2006-01-07 13:18
MRT
Account closed

Registered: Sep 2005
Posts: 149
How to disable default charsets in bank 0 and 2

Is there any way to disable the default charsets in video bank 0 and 2?

A similar question would be... Are al interlaced fli images put in bank 1 and 3?

I mean... for a normal fullscreen fli image you allready need $2000 for the bitmap data and $400 * 8 = $2000 for all the fli color data. Totals $4000, which is exactly the size of one video bank.

So, if you would do this interlaced then you would need two of these video banks, because you have to switch banks every rasterline and flip banks every frame.

So, two complete video banks are needed... Isn't it possible to use... say, bank 1 and 2 ($4000-$7fff and $8000-$bfff)?

Or are all interlaced fli images put at $4000-$7fff and $c000-$ffff???
And if so... Can you still use the last two bytes (sprite pointer registers OR bitmapdata in case of fli) as IRQ vectors??

Questions, questions... so many questions, so few answers... ;-)
2006-01-07 13:36
tlr

Registered: Sep 2003
Posts: 1790
Quote:
Is there any way to disable the default charsets in video bank 0 and 2?

No, these are always seen by the VIC-chip. ($1000-$1fff and $9000-$9fff)
2006-01-07 13:58
MRT
Account closed

Registered: Sep 2005
Posts: 149
So, what you're saying is that all fullscreen interlaced fli images are at $4000-$7fff and $c000-$ffff ???
2006-01-07 14:50
QuasaR

Registered: Dec 2001
Posts: 145
Yep. AFAIK the VIC mirrors "his" charset always to $1000-$2000 and $9000-$a000. Use Google to find the VIC-article, there should be some better answers than mine...
2006-01-07 14:52
Tch
Account closed

Registered: Sep 2004
Posts: 512
You could always place the char at $A000-$BFFF.
Just place the colorscreens at $8000-$9FFF. ;)
2006-01-07 15:17
Graham
Account closed

Registered: Dec 2002
Posts: 990
Only the C128 in C128 mode allows to disable the ROM charsets at $1000 and $9000.

@TCH: nopes, the colorscreens at $9000 would still fetch their colors from character ROM.
2006-01-07 15:23
Tch
Account closed

Registered: Sep 2004
Posts: 512
Ah,totally forgot.
I did use the $8000-$BFFF for a 3rd fli-screen in my last demo.
But that logo didn´t need the $9000,just $8000..
Me bad..
2006-01-07 21:25
Copyfault

Registered: Dec 2001
Posts: 478
What about this Ultimax-Mode? Somewhere I read that the VIC-II sees all RAM when the Ultimaxmode is active... are there no carts that use this feature? And _if_ this is true: is there a way to activate Ultimax per software???
2006-01-08 00:35
MRT
Account closed

Registered: Sep 2005
Posts: 149
Quote: You could always place the char at $A000-$BFFF.
Just place the colorscreens at $8000-$9FFF. ;)


Ehrm... Oh damn... Am I this stupid..? I should quit coding this instance...

I'm going to ask this stupid question anyway...

What do you mean? Are the colorscreens unaffected by the rom charset? Why is this?
So, the VIC isn't always seeing this rom charset, but only if he's looking for pixels and not when he's looking for colors...

k, this gives better opportunities :-) Phew...
2006-01-08 01:08
Oswald

Registered: Apr 2002
Posts: 5094
this is not possible.

if it was it would have been done already.
2006-01-08 01:18
Tch
Account closed

Registered: Sep 2004
Posts: 512
Well,as Graham said,the $9000 region is still a nono for colorscreens aswell.
Guess you´d need a smart painter to solve that problem.
Only using 4 screens instead of 8.
Sorry,no easy way out.. ;)
2006-01-08 07:56
Oswald

Registered: Apr 2002
Posts: 5094
project one can handle such a pic, but I was too lazy to release that version so far.
2006-01-10 12:24
soci

Registered: Sep 2003
Posts: 480
It's possible to disable the character ROM mirrors in hardware as far as I remember I've done it once for fun ;) I think you have to connect GAME and AEC signals together, so when the vic does memory access, it will turn on the ultimax mode as mentioned earlier.
2006-01-10 12:39
Copyfault

Registered: Dec 2001
Posts: 478
Just yesterday I made some fast hack with a RR-using the $DE00-reg one can switch to Ultimax on demand ;) To see if the VIC gets its data from RAM I pointed $D018 to $1000, so I could see the CHAR_ROM_mirror on the screen. Turning on Ultimax makes it disappear and shows the RAMcontents instead ;P

Hope I find some time today to do some quick'n'dirty FLI-routine with Ultimax switched on! If this works (it should!) we could do some quatrolace-FLI-Pics (and let our eyes bleed, yeah).

CF
2006-01-10 12:45
MRT
Account closed

Registered: Sep 2005
Posts: 149
So you did this with a software hack or a hardware hack?

And if it's a software hack...
how did you do it?

and what is "RR"??? (RetroReplay???)
2006-01-10 12:48
MRT
Account closed

Registered: Sep 2005
Posts: 149
"If this works (it should!) we could do some quatrolace-FLI-Pics (and let our eyes bleed, yeah)."

Fullscreen??? And where would you put your code then??? ;-)
2006-01-10 13:15
Ninja

Registered: Jan 2002
Posts: 411
Morris/Agony told me about this not visible charset in Ultimax-mode some years ago. Dunno if he really used it, but as he made a bunch of interesting AR-utilities nevertheless, it might be already somewhere out there...
2006-01-10 14:32
Cruzer

Registered: Dec 2001
Posts: 1048
This reminds me of the old discussion about IUFLI-max (or whatever it was called) ... Anyone knows how that's going?
2006-01-11 13:57
WVL

Registered: Mar 2002
Posts: 902
Quote: Is there any way to disable the default charsets in video bank 0 and 2?

A similar question would be... Are al interlaced fli images put in bank 1 and 3?

I mean... for a normal fullscreen fli image you allready need $2000 for the bitmap data and $400 * 8 = $2000 for all the fli color data. Totals $4000, which is exactly the size of one video bank.

So, if you would do this interlaced then you would need two of these video banks, because you have to switch banks every rasterline and flip banks every frame.

So, two complete video banks are needed... Isn't it possible to use... say, bank 1 and 2 ($4000-$7fff and $8000-$bfff)?

Or are all interlaced fli images put at $4000-$7fff and $c000-$ffff???
And if so... Can you still use the last two bytes (sprite pointer registers OR bitmapdata in case of fli) as IRQ vectors??

Questions, questions... so many questions, so few answers... ;-)


$fffe/$ffff is never displayed :)

bitmaps are only $1f40 bytes, and a colorscreen is $3e8 bytes..
2006-01-11 14:46
MRT
Account closed

Registered: Sep 2005
Posts: 149
:-)

Yeah I know... :-)
I was kinda hoping nobody would see it in the post as I was too late to edit the post after it occured to me.

But hey, thanx... :)
2006-01-11 15:25
Graham
Account closed

Registered: Dec 2002
Posts: 990
@WVL: $FFFE/$FFFF is displayed if you do VSP/AGSP stuff :)
2006-01-11 15:28
JackAsser

Registered: Jun 2002
Posts: 2014
@WVL: Exactly what Graham said... and what I also mentioned in my post in the timer interrupt thread. =)
2006-01-11 15:35
MRT
Account closed

Registered: Sep 2005
Posts: 149
Quote: @WVL: $FFFE/$FFFF is displayed if you do VSP/AGSP stuff :)

What is VSP/AGSP stuff???

Do you mean opening the borders? That would display the $ffff byte when the VIC bank is set to 3
2006-01-11 15:59
Oswald

Registered: Apr 2002
Posts: 5094
$fffe also can be displayed in a sprite

just my 2 smartass cents :D
2006-01-11 16:13
WVL

Registered: Mar 2002
Posts: 902
Quote: $fffe also can be displayed in a sprite

just my 2 smartass cents :D


to be even an übernerd smartass : $ffff can also be displayed in a sprite if you use dirty spritecrunching techniques.. yuck :)

@ graham : ofcourse I was talking about a normal FLI screen :).. tell me about all those problems with sprite-pointers showing up as colors.. blllrrr!! that's even way more horrific than $fffe/$ffff problems..

btw, you can easily-peasily solve $fffe/$ffff by using $0314/$0315 :)
2006-01-12 11:14
Copyfault

Registered: Dec 2001
Posts: 478
Quote: "If this works (it should!) we could do some quatrolace-FLI-Pics (and let our eyes bleed, yeah)."

Fullscreen??? And where would you put your code then??? ;-)


If we're speaking about a "normal" FLI (without any VSP/AGSP-whatsoever-action), you have $c0 bytes at the end of each bitmap - this should be enough for an FLI-routine, even if it utilizes all four banks. A little bit more complicated is to use the mem around $0000-$0200 as the stack and the data direction reg is mapped there...

But basically it works. Just set $DE00 to #$0b before the FLI starts and reset it to #$08 after it (or take care of the IRQ-vectors as set by the RetroReplay), and u can use all of the RAM for the VIC. Note that your FLI_rout must run in some mem_location < $1000, as this is the only available RAM during Ultimax. Should work on AR, too, though I didn't test it.
2006-01-12 13:40
chatGPZ

Registered: Dec 2001
Posts: 11386
mmmh that said, the compo machine on BP will have a retro replay....go and write a demo that exploits that feature :=P
2006-01-12 16:33
Ninja

Registered: Jan 2002
Posts: 411
@smartass WVL: $3f means always end of sprite, even when sprite-crunching, no? ;)
2006-01-12 18:28
JackAsser

Registered: Jun 2002
Posts: 2014
@ninja: if byte $3e (starting with $00) is detected on the third byte on a sprite line, then it's considered complete and will finish, otherwise it will just continue ALWAYS (cheap ass sprite multiplexing).

Perhaps it was this you meant considering you above all people should know this, considering the part in Darwin. =)
2006-01-13 10:02
Ninja

Registered: Jan 2002
Posts: 411
The problem with extreme smartassing is that you sometimes don't see the woods because of so many trees ;)
2006-01-13 10:17
WVL

Registered: Mar 2002
Posts: 902
Quote: The problem with extreme smartassing is that you sometimes don't see the woods because of so many trees ;)


:D
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