Path: utzoo!mnetor!tmsoft!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!elroy.jpl.nasa.gov!ncar!thor.atd.ucar.edu!thor
From: thor@thor.atd.ucar.edu (Richard Neitzel)
Newsgroups: comp.arch
Subject: Re: Let's pretend
Keywords: Intel, 586, windows
Message-ID: <9597@ncar.ucar.edu>
Date: 18 Dec 90 20:49:59 GMT
References: <3042@crdos1.crd.ge.COM> <450@lysator.liu.se>
Sender: news@ncar.ucar.edu
Reply-To: thor@thor.atd.ucar.edu (Richard Neitzel)
Organization: National Center for Atmospheric Research, Remote Sensing Facility
Lines: 45

In article <450@lysator.liu.se>, zap@lysator.liu.se (Zap Andersson) writes:
|> davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr) writes:
|> 
|> >The questions:
|> 
|> >  What features should be put into the CPU to improve performance and
|> >reduce chip count?
|> 
|> Once upon a time I built a graphics board for my computer. 240x240 pixels, 16 
|> shades of gray, not very heavy, BUT I had windows-like support in HARDWARE! 
|> Now I have
|>  NEVER understood why this is not common practice in todays computers! I mean
|> what CAN be easier than to include in the gfx chip that 'when beam reaches
|> this'n'that row/column, start displaying bitmap-data from this'n'that memory!
|> The Amiga is the closes I've seen, supporting these 'semi-hardware' (the
|> amiga uses a co-processor) as horizontal slices of display. With a faster
|> co-processor (i.e. faster than 1 pixel bitclock) you could have hardware
|> windows support! You will NEVER need to worry about memorys overlapping, or
|> in what memory to write! You just write to your 'virtual' screen, and the
|> display chip takes care about it ALL.
|> 
|> Can SOMEONE tell me why this increadibly simple idea have so little use today?
|> 
|> >  Will assumptions about graphics memory organization be made, and if so
|> >what are they?
|> 
|> See above. But if your into 586 Windows handling, try to think up something
|> NEW! Don't bother with standards with moss on top....please?
|> 
If I interpret correctly what you are asking for, check out the Tadpole TP-AGCV graphics 
board. Tadpole has a special windowing chip that allows the following to be set via 
registers: a window's screen x,y start point, it's height and width, the starting 
location in memory, stacking priority, zoom factor and display enable. Moving a window,
[un]displaying it, panning through video memory, setting a window's zoom factor, etc. 
require one or two writes. In our application, we want to switch between multiple windows
nearly instantaneously. The Tadpole board can switch between two sets of two windows
faster then the screen refresh rate - makes a neat display to see both sets of windows
at the same time (just have a loop that swaps the sets constantly!). Currently they 
have a 6U VME board with 4 Mb of video ram, but you can also buy the windowing chips 
from Tadpole.
-- 
Richard Neitzel thor@thor.atd.ucar.edu	     	Torren med sitt skjegg
National Center For Atmospheric Research	lokkar borni under sole-vegg
Box 3000 Boulder, CO 80307-3000			Gjo'i med sitt shinn
303-497-2057					jagar borni inn.