Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!samsung!munnari.oz.au!bruce!labtam!graeme
From: graeme@labtam.labtam.oz (Graeme Gill)
Newsgroups: comp.arch
Subject: Re: Let's pretend
Summary: Usual CISC vs RISC arguments
Keywords: Intel, 586, windows
Message-ID: <5800@labtam.labtam.oz>
Date: 19 Dec 90 05:22:04 GMT
References: <3042@crdos1.crd.ge.COM> <450@lysator.liu.se>
Organization: Labtam Australia, Melbourne, Australia
Lines: 30

In article <450@lysator.liu.se>, zap@lysator.liu.se (Zap Andersson) writes:
>  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?

    The answer to this is the usual RISC vs CISC arguments. Why have very
complicated hardware, that tends to be locked into a particular implementation
of windowing etc. , when with a little bit of effort on the window library
programmers part you can get the same performance with more general hardware
- ie RISC processor and frame buffer. Specialised graphics hardware is usually
about a generation behind mainstream processors. Doing windowing in software
allows a great deal of flexibility in fixing bugs, keeping up with standards
developments, ease of porting code to new generations of hardware, etc., 
    Even some of the high end graphics vendors are throwing out their 
hardware pipelined 3d transform/clip engines, and putting more general
purpose processors in their place, like a bunch of i80860s.
    There is definitely a place for hardware assist of graphics operations,
but "do it all" solutions tend to date rapidly.

	Graeme Gill
	Labtam Australia