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From: bc@cyb-eng.UUCP (Bill Crews)
Newsgroups: net.lang.c
Subject: Re: Uses of "short" ?
Message-ID: <710@cyb-eng.UUCP>
Date: Fri, 13-Sep-85 13:49:53 EDT
Article-I.D.: cyb-eng.710
Posted: Fri Sep 13 13:49:53 1985
Date-Received: Sat, 14-Sep-85 17:01:11 EDT
References: <486@houxh.UUCP> <2761@sun.uucp> <697@cyb-eng.UUCP> <2789@sun.uucp>
Organization: Cyb Systems, Austin, TX
Lines: 28

> Even when writing grubby device driver code, you should use C as a
> higher-level language.  There's no benefit to be gained from thinking of,
> say, the I/O operation/buffer header queue of a disk driver as a bunch of
> words, some of which contain addresses, some of which contain counts, etc..
> The ability of C to get "close to the machine" is vastly overemphasized; 99%
> of the code people write, even in OSes and the like, doesn't need to get
> "close to the machine" in the same sense as an assembler language gets
> "close to the machine" and, in most cases, *doesn't* get "close to the
> machine" in that sense.
> 
> 	Guy Harris

You are invited to write a 3Com Ethernet driver that works on a PC
(16-bit int) and on a Cyb machine (32-bit int) without referring to longs
or shorts.  I.e., a 16-bit hardware register is a 16-bit hardware register,
despite your desire for abstraction.

I doubt we disagree fundamentally; I just think you are stating the case too
strongly.  My goal is to introduce environment dependencies only as needed.
I nevertheless believe, for instance, that when Internet protocol specifies
that the header checksum is a 16-bit 2's-complement number, it is wise to
comply, if you want the packets to fly properly.
-- 
  /  \    Bill Crews
 ( bc )   Cyb Systems, Inc
  \__/    Austin, Texas

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