Newsgroups: comp.arch
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: PMAX/DS3100 frame buffers
Message-ID: <1989Mar22.175616.1420@utzoo.uucp>
Organization: U of Toronto Zoology
References: <93849@sun.Eng.Sun.COM> <5845@mit-vax.LCS.MIT.EDU>
Date: Wed, 22 Mar 89 17:56:16 GMT

In article <5845@mit-vax.LCS.MIT.EDU> keith@mit-vax.UUCP (Keith Packard) writes:
>I'd rather see special blt hardware though.  I can imagine all sorts
>of fun uses (like system/user data copy) for a fast piece of general
>memory copy hardware.

Before asking for copy hardware, find out whether your CPU is good enough
(when programmed carefully) to saturate the memory bandwidth doing copying.
Many modern CPUs are, which means that simple data copying cannot possibly
be speeded up with a hardware copier.  To see real benefits, you either
need a memory system that the CPU cannot fully exploit, or some additional
complexity in the operation to be done that slows the CPU down.
-- 
Welcome to Mars!  Your         |     Henry Spencer at U of Toronto Zoology
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