| VicII Video Emulation Question... [message #141706] |
Thu, 17 November 2005 23:07  |
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Originally posted by: Jim Agla
Everyone is going think this is crazy, but I am working on an C64 emulator
written in Visual Basic 2005 (This is where everyone says "Basic is not fast
enough, blah, blah.) I am not doing this to make it a usable emulator to
play games on... others have already done that. I am doing it for my own
satisfaction and my own curiosity. I have the 6502 emulated almost perfectly
thanks to other sources I have found on the internet. The kernal runs
perfectly (matched it up with the Monitor in WinVice) until it starts
looking for the Vic II changing memory location $D012 (See Kernal Location
$FF5E). But for the life of me, I cannot find a whole lot of information on
how to emulate the Vic II video chip anywhere. I have tried examining source
code for WinVice, but I don't know C++ that well to understand what is going
on. I may sleep on it tonight and look at the source again tomorrow, but I
am also hoping someone can help out a little and point me to something I
have not found online.
Any help is appreciated...
Jim
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| Re: VicII Video Emulation Question... [message #141707 is a reply to message #141706] |
Thu, 17 November 2005 23:28  |
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Originally posted by: LocalH
Jim Agla wrote:
> Everyone is going think this is crazy, but I am working on an C64 emulator
> written in Visual Basic 2005 (This is where everyone says "Basic is not fast
> enough, blah, blah.) I am not doing this to make it a usable emulator to
> play games on... others have already done that. I am doing it for my own
> satisfaction and my own curiosity. I have the 6502 emulated almost perfectly
> thanks to other sources I have found on the internet. The kernal runs
> perfectly (matched it up with the Monitor in WinVice) until it starts
> looking for the Vic II changing memory location $D012 (See Kernal Location
> $FF5E). But for the life of me, I cannot find a whole lot of information on
> how to emulate the Vic II video chip anywhere. I have tried examining source
> code for WinVice, but I don't know C++ that well to understand what is going
> on. I may sleep on it tonight and look at the source again tomorrow, but I
> am also hoping someone can help out a little and point me to something I
> have not found online.
>
> Any help is appreciated...
>
> Jim
>
>
>
http://www.minet.uni-jena.de/~andreasg/c64/vic_artikel/vic_a rticle_1.htm
This should help you out quite a bit. It's a bit advanced, but as far as
I know it's the best dissection of how the VIC-II operates.
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| Re: VicII Video Emulation Question... [message #141708 is a reply to message #141706] |
Fri, 18 November 2005 02:53 |
Golan Klinger
Messages: 559
Registered: December 2004
Karma: 0
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Senior Member |
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Jim Agla wrote:
> Everyone is going think this is crazy, but I am working on an C64 emulator
> written in Visual Basic 2005
> [...]
> I am doing it for my own satisfaction and my own curiosity.
I don't think you're crazy. I think it's great. You're learning and having
fun while doing something cool. My hat is off to you.
The advice given by the previous poster is excellent. Christian Bauer's
article "The MOS 6567/6569 video controller (VIC-II) and its application
in the Commodore 64" should answer all your questions. It's an amazing
resource and a really interesting read.
--
Golan Klinger
Dark is the suede that mows like a harvest.
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| Re: VicII Video Emulation Question... [message #141710 is a reply to message #141707] |
Fri, 18 November 2005 14:35 |
David Horrocks
Messages: 34
Registered: December 2012
Karma: 0
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Member |
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Hi,
Christian Bauer's VIC-II Article is truly amazing. Its essential reading for
any emulator writer. The information is accurate in everything it says. If
you write your emulator by following this doc to the letter, then you will
have a very fine VIC-II emulation that will run almost anything.
A couple of points are missing from the article. These points may seem minor
compared with the huge amount of correct information in the doc.
1) How precisely do sprites behave when positioned near to the sprite data
fetch clocks? I would love to know the answer to this.
Please, does anyone know about this?
2) The explanation of what happens when writting to Sprite Y Expand register
is not really wrong but is not the full story. I believe I have an answer
for this if anyone needs it.
3) How long the VIC-II takes to respond to changes in XScroll, MCM, ECM and
BMM modes and colour regs are a little gray.
4) How 6510 interrupts are affected when the VIC decides to halt the
processor. I believe I have an answer for this if anyone needs it.
Regards
David
"LocalH" <localnospamh@charternospamtn.net> wrote in message
news:HLcff.75491$RG4.66740@fe05.lga...
> Jim Agla wrote:
>> Everyone is going think this is crazy, but I am working on an C64
>> emulator written in Visual Basic 2005 (This is where everyone says "Basic
>> is not fast enough, blah, blah.) I am not doing this to make it a usable
>> emulator to play games on... others have already done that. I am doing it
>> for my own satisfaction and my own curiosity. I have the 6502 emulated
>> almost perfectly thanks to other sources I have found on the internet.
>> The kernal runs perfectly (matched it up with the Monitor in WinVice)
>> until it starts looking for the Vic II changing memory location $D012
>> (See Kernal Location $FF5E). But for the life of me, I cannot find a
>> whole lot of information on how to emulate the Vic II video chip
>> anywhere. I have tried examining source code for WinVice, but I don't
>> know C++ that well to understand what is going on. I may sleep on it
>> tonight and look at the source again tomorrow, but I am also hoping
>> someone can help out a little and point me to something I have not found
>> online.
>>
>> Any help is appreciated...
>>
>> Jim
>>
>>
>>
> http://www.minet.uni-jena.de/~andreasg/c64/vic_artikel/vic_a rticle_1.htm
>
> This should help you out quite a bit. It's a bit advanced, but as far as I
> know it's the best dissection of how the VIC-II operates.
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