Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!snorkelwacker!apple!altos!altos86!rcollins
From: rcollins@altos86.Altos.COM (Robert Collins)
Newsgroups: comp.sys.ibm.pc.misc
Subject: Re: 386SX capabilites
Message-ID: <4255@altos86.Altos.COM>
Date: 15 Oct 90 23:18:04 GMT
References: <1990Oct9.212047.21053@infonode.ingr.com> <1990Oct10.001733.1299@thyme.jpl.nasa.gov> <2056@sixhub.UUCP> <1990Oct15.161015.417@thyme.jpl.nasa.gov>
Reply-To: rcollins@altos86.UUCP (Robert Collins)
Organization: Altos Computer Systems, San Jose, CA
Lines: 22

In article <1990Oct15.161015.417@thyme.jpl.nasa.gov> kaleb@thyme.jpl.nasa.gov (Kaleb Keithley	) writes:
>>  Whoops! The 16 bit data bus prevents doing 32 bit i/o to memory mapped
>>devices, and the addressing space is only 16 MB.
>>
>
>Got any memory mapped devices in mind?  We are talking about Intel 
>architecture here, not Motorola ;-)  Accuse me of "small world" if you
>want, I haven't seen memory mapped i/o for PC's in ten years, that's
>what the i/o bus is for.  

Try being a BIOS programmer and dealing with custom and standard chip 
sets.  We have memory mapped I/O on lots of machines in the address
ranges from 80000000h - A001FFFFFh.  

I assure you, there are plenty of machines that use memory mapped
I/O.

-- 
"Worship the Lord your God, and serve him only."  Mat. 4:10
Robert Collins                 UUCP:  ...!sun!altos86!rcollins
HOME:  (408) 225-8002
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