From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-0.4 required=5.0 tests=AC_FROM_MANY_DOTS,BAYES_00 autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,daaf4964abae8ea7 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2001-08-23 11:55:03 PST Path: archiver1.google.com!newsfeed.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!newsfeeds.belnet.be!news.belnet.be!psinet-eu-nl!psiuk-p4!uknet!psiuk-n!news.pace.co.uk!nh.pace.co.uk!not-for-mail From: "Marin David Condic" Newsgroups: comp.lang.ada Subject: Re: Ada And Alternate System Architectures Date: Thu, 23 Aug 2001 14:45:00 -0400 Organization: Posted on a server owned by Pace Micro Technology plc Message-ID: <9m3ivd$bu9$1@nh.pace.co.uk> References: <3B8528F1.7B664D21@lmtas.lmco.com> <9m3dcp$9vk$1@nh.pace.co.uk> <3B8549D8.A4E3A04A@lmtas.lmco.com> NNTP-Posting-Host: dhcp-200-133.miami.pace.co.uk X-Trace: nh.pace.co.uk 998592301 12233 136.170.200.133 (23 Aug 2001 18:45:01 GMT) X-Complaints-To: newsmaster@news.cam.pace.co.uk NNTP-Posting-Date: 23 Aug 2001 18:45:01 GMT X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 5.50.4522.1200 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4522.1200 Xref: archiver1.google.com comp.lang.ada:12356 Date: 2001-08-23T18:45:01+00:00 List-Id: Clearly, you need to read Chapter 13. If you are trying to do low level system dependent things - or build things where the representation can be controlled to be system independent, this is the chapter for you. Specifically, see: 13.5.3 Bit Ordering 13.3 Representation Attributes You can learn to use clever things like "for S'Bit_Order use High_Order_First ;" and similar clever things by getting familiar with Chapter 13. MDC -- Marin David Condic Senior Software Engineer Pace Micro Technology Americas www.pacemicro.com Enabling the digital revolution e-Mail: marin.condic@pacemicro.com Web: http://www.mcondic.com/ "Gary Scott" wrote in message news:3B8549D8.A4E3A04A@lmtas.lmco.com... > Hi, > > Thanks. Fortran 95 defines a bit model for integers and then provides > intrinsics for manipulating bits within that bit model. What I was > wanting was a key word optional argument for bit manipulation intrinsics > that allowed me to very slightly modify the bit model by specifying an > "endian" (byte) key word. This would allow me to write "portable" code > between big/little endian 8-bit byte systems. Apparently if it's only > 99.9% portable or acknowledges the existence of a "byte", it can't be > considered. I guess I understand, but it seems like this could be > addressed through an architecture/system dependent modularized > definition. > > Marin David Condic wrote: > > > > Ada bends over backwards to avoid specifying anything that would make it > > impossible or impractical to implement Ada on just about any platform. For > > example, Ada specifies Streams which will most often be implemented as 8-bit > > bytes, but the element type is defined in terms of some system defined > > storage unit - so it could be 16-bit words or anything else you like. > > Similarly, the standard integer types have a minimum range required. For > > example, ARM 3.5.4(21) says: > > > > 21 In an implementation, the range of Integer shall include the > > range -2**15+1 .. +2**15-1. > > > > That would suggest at least 16 bits - but it could be (and often is) 32 > > bits. On a PDP-10 it might be 36 bits. > > > > Ada does exist on processors that aren't 8-bit byte machines. The > > Mil-Std-1750a comes immediately to mind. > > > > MDC > > -- > > Marin David Condic > > Senior Software Engineer > > Pace Micro Technology Americas www.pacemicro.com > > Enabling the digital revolution > > e-Mail: marin.condic@pacemicro.com > > Web: http://www.mcondic.com/ > > > > "Gary Scott" wrote in message > > news:3B8528F1.7B664D21@lmtas.lmco.com... > > > Hi, > > > > > > A very naive question...does the Ada standard adequately address > > > non-8-bit byte computers? The Fortran language standard committee > > > consistently avoids defining anything that relates to a specific > > > computer architecture implementation (because what if 6-bit character > > > systems one day become common again...). At a very high level, how are > > > machine specifics addressed?