Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!rutgers!cbmvax!jesup
From: jesup@cbmvax.commodore.com (Randell Jesup)
Newsgroups: comp.sys.amiga.tech
Subject: Re: 3000 memory map causes problem.  need advice.
Message-ID: <16655@cbmvax.commodore.com>
Date: 19 Dec 90 04:21:56 GMT
References: <1990Dec3.041120.1142@acc.stolaf.edu>
Reply-To: jesup@cbmvax.commodore.com (Randell Jesup)
Organization: Commodore, West Chester, PA
Lines: 36

In article <1990Dec3.041120.1142@acc.stolaf.edu> henning@thor.acc.stolaf.edu () writes:
>This is the scoop.  Since all unix systems are remaped by mmu's all
>programs start at a virtual address of zero.  Richard Stallman ( or
>someone in his employ) decided that noone in his or her right mind
>would ever edit files over sixteen megabytes large.  Therefore they
>thought that leaving 24 bits for pointers would be sufficient.

	Ah yes, the wonders of Stallman "he-man" C/Lisp code.

>I have spent about two hours puting in statemnts like
>#ifdef NEED_ALL_BITS
>   Lisp_Object foo;
>#else
>   register Lisp_Object foo;
>#endif
>when I come to the problem that often these structures are returned as
>the value pof a function.  This is much more difficult to fix.

	Much better solution: let the optimizer do it's job, and add a
-Dregister to the flags in the makefile.  Also, modern compilers allow
structure assignments and returns.

>Musing to myself, I come across an idea.  All3000s are 68030 machines.
>This means that they have an mmu embeded within them.
>Would it be possible to write a loader which wuold set up the mmu to
>relocat memory for the single porcess of emacs?  

	No.  (Dave gave a reasonable explanation, not including the fact 
that A3000's already use the MMU.)

-- 
Randell Jesup, Keeper of AmigaDos, Commodore Engineering.
{uunet|rutgers}!cbmvax!jesup, jesup@cbmvax.commodore.com  BIX: rjesup  
The compiler runs
Like a swift-flowing river
I wait in silence.  (From "The Zen of Programming")  ;-)