From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 28806 invoked by alias); 30 Sep 2002 05:08:51 -0000 Mailing-List: contact gdb-patches-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sources.redhat.com Received: (qmail 28794 invoked from network); 30 Sep 2002 05:08:50 -0000 Received: from unknown (HELO otisco.McKusick.COM) (209.31.233.190) by sources.redhat.com with SMTP; 30 Sep 2002 05:08:50 -0000 Received: (from hilfingr@localhost) by otisco.McKusick.COM (8.9.3/8.9.3) id WAA30245; Sun, 29 Sep 2002 22:10:10 -0700 Date: Sun, 29 Sep 2002 22:08:00 -0000 Message-Id: <200209300510.WAA30245@otisco.McKusick.COM> X-Authentication-Warning: localhost.localdomain: hilfingr set sender to hilfingr@otisco.mckusick.com using -f From: "Paul N. Hilfinger" To: drow@mvista.com CC: gdb-patches@sources.redhat.com In-reply-to: <20020930010515.GA27762@nevyn.them.org> (message from Daniel Jacobowitz on Sun, 29 Sep 2002 21:05:15 -0400) Subject: Re: RFA/types: Clean up use of field bitsize Reply-to: Hilfinger@otisco.mckusick.com References: <20020930010515.GA27762@nevyn.them.org> X-SW-Source: 2002-09/txt/msg00742.txt.bz2 > So, since I needed to gain a new field here anyway, and since I have no > compunctions about shrinking this field a little (packed bitfields of size > greater than a couple of words are allowed in some languages IIRC (including > GNU C maybe? Although they are not allowed in ISO C99), but they're > definitely dodgy), and since signed bitfields are not portable, I cleaned up > the construct. It turned out to be painless except for making sure symbol > readers initialized it, which was a little tedious. Well, as it happens, Ada IS able to handle bit fields of arbitrary size. However, given that you have left 29 bits (unsigned), and that the gain from decreasing one's memory usage by 0.000006% (31 bits of 2**29) is insignificant compared to the enormous cost of extracting 2**29-bit, arbitrarily aligned fields, I'd say that this change is reasonable (:->). P. Hilfinger Ada Core Technologies, Inc.