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Sam Technical Manual

Submitted by Dan Dooré on Tue, 2006-05-16 18:47. Other

MGT


Bruce Gordon Dr Andy Wright Gary Thomas Adrian Parker


The Technical Manual.

First published 1989 by Miles Gordon Technology, Updated and republished 1990.
Republished 1991 by Sam Computers Ltd.
Republished 1992 by Format Publications.

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hmpr bits 5&6

Submitted by rogerjowett on Wed, 2011-01-26 03:36.

doesn’t explain terribly well how to use them to get 16 colours on mode 3 screen - does this extra four bits alter the palette colours that are displayed - so for one bit modified four different colours are displayed on screen?
has anyone figured out how to use this?
what a shame mode 4 couldn’t have three more sets of 16 palette clut entries for 64 colours onscreen - more than the amiga!

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Re: hmpr bits 5&6

Submitted by ascii on Wed, 2011-01-26 22:50.

There isn’t a convenient way to get 16 colours on the screen in mode 3. It’s better to think of these bits as offering a quick way to switch between four different palettes of four colours.

So, in general, you can’t put more than 4 colours on the screen at a time, certainly no more than 4 in every 48 horizontal pixels. You could change the colours between scan lines fairly easily, or (if you’re very careful, and willing to spend a lot of the cpu time doing it) a few times vertically on the screen. But it’s really not much more effective than changing the palette colours.

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Submitted by rogerjowett on Thu, 2011-01-27 17:34.


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Submitted by rogerjowett on Wed, 2011-02-02 04:08.


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