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Jiffydos Color Hacks..

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Dmackey828

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Jul 1, 2009, 8:19:10 PM7/1/09
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Hello All,
I decided to figure out how to change the default colors on my C128 in
64 mode. Was getting tired of the BLUE screen...

I can hear some of you yelling now. WHAT!!!

Well anyways, I wrote up how I did it. You can
read about how I did it here : http://www.n2dvm.com/mod-jd.html
or goto my main site http://www.n2dvm.com and click on the
information link. Look for Jiffydos color hacks and click on it.

Have a good one and enjoy the information..

iAN CooG

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Jul 4, 2009, 8:00:14 AM7/4/09
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Dmackey828 <n2...@NOSPAMarrl.net> wrote:
> Hello All,
> I decided to figure out how to change the default colors on my C128 in
> 64 mode. Was getting tired of the BLUE screen...
>
> I can hear some of you yelling now. WHAT!!!

Yeah, WHAT?
Changing colors in the kernal rom is one of the first "hacking" attempts
anyone did. Welcome =)

> Well anyways, I wrote up how I did it. You can
> read about how I did it here : http://www.n2dvm.com/mod-jd.html

you say to search for
"8C02A907"
but normally the text is not yellow but light blue so better change it to
"8C02A90E"

Also an explanation of WHY these changes take place at those locations would
be interesting to understand better.
Following the Kernal disassembly you'll notice that on reset ($fce2) it
executes:

$E518/58648: Initialize I/O

E518: 20 A0 E5 JSR $E5A0 ; Set I/O Defaults
[...]
E534: A9 0E LDA #$0E <<< the text color
E536: 8D 86 02 STA $0286 ; Current Character Color code

[...]

$E5A0/58784: Set I/O Defaults

which at some point copies the default VIC-II values to $d000

E5A8: A2 2F LDX #$2F
E5AA: BD B8 EC LDA $ECB8,X
E5AD: 9D FF CF STA $CFFF,X
E5B0: CA DEX
E5B1: D0 F7 BNE $E5AA
E5B3: 60 RTS

$ECB9/60601: Video Chip Setup Table

ECB9: 00 00 00 00 00 00 00 00 ; copied to $d000
ECC1: 00 00 00 00 00 00 00 00 ; copied to $d008
ECC9: 00 9B 37 00 00 00 08 00 ; copied to $d010
ECD1: 14 0F 00 00 00 00 00 00 ; copied to $d018
ECD9: 0E 06 01 02 03 04 00 01 ; copied to $d020 <<< the screen colors
ECE1: 02 03 04 05 06 07 ; copied to $d028

--
-=[]=--- iAN CooG/HVSC & C64Intros ---=[]=-


Dmackey828

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Jul 6, 2009, 1:05:12 PM7/6/09
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On Sat, 4 Jul 2009 14:00:14 +0200, "iAN CooG"
<GETian...@OFemailME.it.invalid> wrote:
<SNIP>

>
>you say to search for
>"8C02A907"
>but normally the text is not yellow but light blue so better change it to
>"8C02A90E"
>

You are correct, My fault. It should have been the "8C02A90E"
instead. Thanks for pointing that out. I changed it on my page.


Have a good one.

WEB: http:/www.n2dvm.com

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