Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/5/84; site osu-eddie.UUCP Path: utzoo!watmath!clyde!cbosgd!osu-eddie!pritch From: pritch@osu-eddie.UUCP (Norman Pritchett) Newsgroups: net.lang.c Subject: Re: register variables Message-ID: <421@osu-eddie.UUCP> Date: Sat, 29-Jun-85 19:55:53 EDT Article-I.D.: osu-eddi.421 Posted: Sat Jun 29 19:55:53 1985 Date-Received: Sun, 30-Jun-85 02:16:29 EDT References: <472@crystal.UUCP> <365@umcp-cs.UUCP> Distribution: net Organization: Ohio State Univ., CIS Dept., Cols, Oh. Lines: 28 Just for the sake of information, VMS ignores register declarations and automatically decides for itself how frequently you use each variable and whether or not to make it a "register declaration". I personally don't think this is the wisest approach but after looking at a number of machine code listings it actually appears to work well under most conditions. > > From: shekita@crystal.UUCP > > > > How many variables can be declared as registers on a Vax 780? In > > general, is there some way to tell how many register variables can > > be declared? > > Depends on the compiler. Most Unix compilers have 6 registers on > Vaxen (r11-r6). VMS uses r12-r2 (!), though I don't know how their > compiler reacts to register declarations. Sun's C compiler has 4 > register pointers (a5-a2) and 6 register integers (d7-d2). (I think.) > -- > In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 4251) > UUCP: seismo!umcp-cs!chris > CSNet: chris@umcp-cs ARPA: chris@maryland -- ----------------------------------- Norm Pritchett UUCP: cbosgd!osu-eddie!pritch CSNET: pritch@ohio-state BITNET: TS0017 at OHSTVMA MA-NET: (614) 291-8775