Path: utzoo!attcan!uunet!mcsun!ukc!edcastle!aiai!richard
From: richard@aiai.ed.ac.uk (Richard Tobin)
Newsgroups: comp.lang.c
Subject: Re: a style question
Message-ID: <3480@skye.ed.ac.uk>
Date: 3 Oct 90 17:00:30 GMT
References: <7341@darkstar.ucsc.edu> <8660@ncar.ucar.edu> <1990Sep30.194448@IASTATE.EDU> <557@iccdev.indcomp.com>
Reply-To: richard@aiai.UUCP (Richard Tobin)
Organization: AIAI, University of Edinburgh, Scotland
Lines: 17

In article <557@iccdev.indcomp.com> jd@iccdev.indcomp.com (J.D. Laub) writes:
>john@IASTATE.EDU (Hascall John Paul) writes:
>I beleive one HP optimizer manual recommened pre inc/dec, but I cannot
>find the manual to confirm.  Anyone know why they made this recommendation?

Some processors have auto-increment/decrement addressing modes, and
some of them do not have both pre- and post- forms.  For example, (if
I recall correctly) the PDP-11 had post-increment and pre-decrement,
but not the other two.  The asymmetry makes sense for implementing
stacks.

-- Richard

-- 
Richard Tobin,                       JANET: R.Tobin@uk.ac.ed             
AI Applications Institute,           ARPA:  R.Tobin%uk.ac.ed@nsfnet-relay.ac.uk
Edinburgh University.                UUCP:  ...!ukc!ed.ac.uk!R.Tobin