Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site abnjh.UUCP Path: utzoo!watmath!clyde!floyd!whuxle!spuxll!abnjh!usenet From: usenet@abnjh.UUCP (usenet) Newsgroups: net.arch,net.lang.c Subject: Re: RISC perspective -- register variables Message-ID: <502@abnjh.UUCP> Date: Wed, 14-Mar-84 10:27:29 EST Article-I.D.: abnjh.502 Posted: Wed Mar 14 10:27:29 1984 Date-Received: Thu, 15-Mar-84 07:24:55 EST References: <936@hou5e.UUCP> Organization: ATTIS, NJ Lines: 14 The keyword 'register' does not mean just 'fast' !!! It also means that there will never be a pointer to that variable. (Technically, there can be no 'aliasing' problems for register variables.) Thus, it is meaningful and potentially useful for you to declare all the variables in a program to be register storage class. The compiler can apply certain optimizations if it knows there are no aliases for a particular variable. Those optimizations are not 'safe' to apply in the general case. PCC, at least, enforces this restriction; you cannot apply the '&' operator to a register variable. Rick Thomas ihnp4!abnji!rbt or ihnp4!abnjh!usenet