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From: hadeishi@husc7.HARVARD.EDU (Mitsuharu Hadeishi)
Newsgroups: comp.sys.mac
Subject: Re: Bit Blitters
Message-ID: <1359@husc6.UUCP>
Date: Tue, 10-Mar-87 01:12:00 EST
Article-I.D.: husc6.1359
Posted: Tue Mar 10 01:12:00 1987
Date-Received: Tue, 10-Mar-87 19:09:59 EST
Sender: news@husc6.UUCP
Reply-To: hadeishi@husc7.UUCP (Mitsuharu Hadeishi)
Distribution: world
Organization: Harvard Univ. Science Center
Lines: 32
Summary: There are existing blitters much faster than a 68K

In <43140@beno.seismo.CSS.GOV> mo@seismo.CSS.GOV (Mike O'Dell) writes:
>The only problem with bit blitters is that none of 
>the chips available actually do what you want in
>all the cases.  Tom Duff tried to use the
>old SUN blackk/white hardware assist to do the
>equivalent of a Blit and discovered it took
>over 30 times as much code and ran much slower
>to really try and use the beast.  A vanilla 68K
>can blit faster than any currently known hardware
>chip.

	No no no no no.  A vanilla 68K is a pretty poor blitter;
even the Sun blitters can easily outstrip a 68K.  You need at least
a 68010 to get reasonable performance on memory moves (the 68010
in tight loop mode is reasonably fast.)  However, the series of
recently announced graphics powerhouses such as the TI graphics processor
blow away a 68000 without blinking an eye.  Even the Atari blitter
in reported to speed graphics operations on the ST by a factor of ten
(probably highly exaggerated, but a factor of two or three would not
be surprising.)  The Amiga custom chips, three of them, are a full-blown
graphics/sound/IO coprocessor which achieve blit speeds at or exceeding
that of a 68020 even on a 7 Mhz bus.  And they of course do all that
in color.  All those blit calls, by the way, are easily accessed through
the Amiga relocatable system libraries.

>So, who keeps
>perpetuaing this myth that you gotta have
>hardware or it ain't chic??

	Me.

					-Mitsu