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From: breuel@harvard.ARPA (Thomas M. Breuel)
Newsgroups: net.micro.68k
Subject: Re: Why no INC or DEC
Message-ID: <310@harvard.ARPA>
Date: Mon, 21-Jan-85 06:55:01 EST
Article-I.D.: harvard.310
Posted: Mon Jan 21 06:55:01 1985
Date-Received: Wed, 23-Jan-85 05:48:51 EST
Distribution: net
Organization: Harvard University
Lines: 16

> wince when I see "ADDQ #1,D0", even if it does have a Q in it. I claim
> this is a natural tendency, since this kind of thing really is inefficient
> on other CPU's.  I advise making an INC and DEC macro if you also have this
> tendency.

"ADDQ" makes sense on a 68000, since you have to increment not only by 1
(for pointers to bytes), but also by 2 and 4 (for pointers to words and
longwords respectively). "INC" and "DEC" are anachronisms from processors
like the Z80.

I would actually recommend you to leave out the "Q" in the instruction.
MOTOROLA assemblers and compatibles automatically use the shortest
instruction possible, and assembly language listings look a lot nicer if
they are not cluttered with instruction modifiers.

						Thomas.