Article View: comp.sys.ibm.pc.misc
Article #11870Re: Setting Colors on ET4000 without Interrupt ?
From: Phil Willows
Date: Wed, 27 Jan 1993 22:36
Date: Wed, 27 Jan 1993 22:36
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1479 bytes
p7003ag@sun1.LRZ-Muenchen.DE writes:
>Yoho !
>can anybody please tell me, how to set the Colorvalues (the 18bit ones)
>on my ET4000 without using the BIOS Interrupt ?
>Alaric
You weren't specific about what it is you are asking for, but here goes...
When you set a pixel to a value, you are actually placing a index to a
lookup table into video memory. The lookup table points to a three byte
area that changes the appearance of the pixel. The ET4000 is pretty
much standard in this respect.
By setting register 0x3C8 to the index you wish to change, you
then send three consecutive bytes to 0x3C9. The first byte controls
the red, the second green, and the third blue.
Just remember, every pixel that is set to that index will change when
you set its palette entry.
DON'T MESS WITH THE LOOKUP TABLE.
The lookup table can be modified to look at the same palette entry as
another table entry. It can be a real spaghetti bowl problem.
-Phil
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Path: arc1-ca.pugleaf.net!sparky!uunet!ukma!darwin.sura.net!udel!gvls1!faatcrl.faa.gov!phil From: phil@tgf.tc.faa.gov (Phil Willows) Newsgroups: comp.sys.ibm.pc.misc Subject: Re: Setting Colors on ET4000 without Interrupt ? Date: 27 Jan 1993 22:36:35 GMT Organization: FAA Technical Center, Pomona, NJ Lines: 33 Distribution: world Message-ID: <1k72pjINNq41@faatcrl.Faa.Gov> References: <p7003ag.727108180@sun1> NNTP-Posting-Host: offserv2.faa.gov Keywords: ET4000 interrupt colors