Xref: utzoo comp.arch:17154 comp.compilers:1052
Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!usc!samsung!uunet!lotus!esegue!compilers-sender
From: aglew@dwarfs.crhc.uiuc.edu (Andy Glew)
Newsgroups: comp.arch,comp.compilers
Subject: Re: Register Allocation and Aliasing
Keywords: optimize, code
Message-ID: <1990Jul16.150553.23357@esegue.segue.boston.ma.us>
Date: 16 Jul 90 15:05:53 GMT
References: <1990Jul06.194618.4957@esegue.segue.boston.ma.us>
	<1990Jul15.205606.19343@esegue.segue.boston.ma.us>
Sender: compilers-sender@esegue.segue.boston.ma.us
Reply-To: aglew@dwarfs.crhc.uiuc.edu (Andy Glew)
Followup-To: comp.arch,comp.compilers
Organization: University of Illinois, Computer Systems Group
Lines: 36
Approved: compilers@esegue.segue.boston.ma.us
In-Reply-To: mike@vlsivie.at's message of 15 Jul 90 20:56:06 GMT

>IT EVEN HAS A NAME: it's called ``cache memory''. Access times are short 
>and if integrated on the chip can be as fast as a register access.

As I am sure Mr. Gschwind knows, cache implemented on-chip is not as
fast as register access, chiefly because cache is seldom multiported,
as well as for other reasons such as loading, and the number of
addresses that can be specified in an instruction.

If you will, we are talking about the space formed by the
cross-product of the following parameters:

    ADDRESSING = by memory address and/or by register number

    MULTIPORTING = 1r/w .. 2r/1w ...

    SIZE/SPEED = large/slow .. small/fast

The standard configurations are 

    CACHE = addressed by memory address (associatively)
    	    single-ported
    	    large/slow (at least wrt. registers)

    REGISTER = addressed by number
    	       multiported
    	       small/fast

What I was asking about, and what Hank Dietz et al, and others, have
explored, is whether there are other configurations between these two
extremes that might be useful.  

--
Andy Glew, aglew@uiuc.edu
-- 
Send compilers articles to compilers@esegue.segue.boston.ma.us
{spdcc | ima | lotus| world}!esegue.  Meta-mail to compilers-request@esegue.