Date: Mon, 9 Jun 1997 09:16:37 -0400 (EDT)
From: "Art S. Kagel" <kagel AT ns1 DOT bloomberg DOT com>
To: Liam <marl AT rmplc DOT co DOT uk>
Cc: Mlsoftware <mlsoftware AT aol DOT com>, djgpp AT delorie DOT com
Subject: Re: 32 bit Memory Operations
In-Reply-To: <199706062045.UAA14496@mx2.rmplc.co.uk>
Message-Id: <Pine.D-G.3.91.970609085751.23601B-100000@dg1>
Mime-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Precedence: bulk

On Fri, 6 Jun 1997, Liam wrote:

> Mlsoftware <mlsoftware AT aol DOT com> wrote:
> > words rather than bytes, as they copy 4 bytes at a time.
> > 1 WORD =  4 BYTES, so when you tell it how many words to copy, make sure
> Thats wrong, ONE WORD is equilivant to TWO BYTES NOT FOUR.
> 

This comes up periodically and I just let it slide but no-one has ever 
attempted to CORRECT another's notation before so I feel compelled to 
step in an clarify the issue.  Let's come to some agreement about 
notation for DJGPP.  Toward this end I submit:

Originally a 'word' was the natural word size of the CPU.  This was a 
great idea when computers were all 16bits (ignoring of course 
DEC10/20's 36bit word and Honeywell's 48bit word) in the case of 
the 8086->80286 that was 16bits (2bytes) in the case of a 386->Pentium 
Pro a word would be 32bits or 4bytes, while on the DEC Alpha CPU a word 
in the original sense is 64bits or 8bytes.

Due to the confusion this causes when a 32bitWorder speaks to a 
16bitWorder, etc., a new standard developed over the years.  We should 
all be saying that a word is 32bits, a half word is 16bits, and a double 
word is 64bits.  Since a byte is already standard there is no need to 
call one a 'quarter-word' while a half-byte is a nibble.

This is the standard in the mini/mainframe world and I see no reason for 
the DJGPP community to base its notation on an obsolete group of CPUs 
(i8086 -> 80286) that our compiler does not even support.  I, therefore, 
side with the original posting and further propose that we all adopt this 
notation.

Art S. Kagel, kagel AT bloomberg DOT com