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=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID
	autolearn=no autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,8309f2bc055237c4
X-Google-Attributes: gid103376,public
From: "Martin Dowie" <martin.dowie@gecm.com>
Subject: Re: Bit manipulation
Date: 2000/11/14
Message-ID: <3a110356$1@pull.gecm.com>#1/1
X-Deja-AN: 693410005
References: <8u8v6n$b7o$1@nnrp1.deja.com> <2WTH$pdrCfOd@eisner.decus.org>
 <8ub6kt$6nd$1@nnrp1.deja.com> <8ubeq8$cgm$1@nnrp1.deja.com>
 <3A0D38E9.BB87D8CD@mindspring.com> <slrn90vl0k.l5.lutz@taranis.iks-jena.de>
 <8uoq5g$of6$1@nnrp1.deja.com> <slrn90vt78.l5.lutz@taranis.iks-jena.de>
 <8up1j4$uqe$1@nnrp1.deja.com> <slrn9104p4.l5.lutz@taranis.iks-jena.de>
X-Trace: 14 Nov 2000 09:18:14 GMT, superted.dsge.edinbr.gmav.gecm.com
X-MSMail-Priority: Normal
X-Priority: 3
Newsgroups: comp.lang.ada
X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300
Date: 2000-11-14T00:00:00+00:00
List-Id: <comp.lang.ada>

er, you realize that the "'Bit_Order" here is unnecessary? try it - it
will make no difference if you comment them out (or make them the
same) as they simply provide a way of referencing bits
(i.e. High_Order_First = bit(0)MSB, Low_Order_First = bit(0)LSB)
and you don't reference any bit positions!

What you have tried to acheive by the use of 'Bit_Order, you have
done by actually doing the assignments. 'Bit_Order played no part.

Lutz Donnerhacke <lutz@iks-jena.de> wrote in message
news:slrn9104p4.l5.lutz@taranis.iks-jena.de...
[snip]
> with Ada.Unchecked_Conversion;
> with System;
>
> procedure endian is
>   type word8 is mod 2**8;
>   type word32 is mod 2**32;
>   type composite is array (1..4) of word8;
>   pragma Pack(composite);
>
>   type  lowrec is record   val: composite;   end record;
>   type highrec is record   val: composite;   end record;
>   for  lowrec'Bit_Order use System.Low_Order_First;
>   for highrec'Bit_Order use System.High_Order_First;
>
>   function w32tohigh is new Ada.Unchecked_Conversion(word32, highrec);
>   function lowtow32  is new Ada.Unchecked_Conversion(lowrec, word32);
>
>   function h2l32 (h : word32) return word32 is
>      hr : highrec := w32tohigh (h);
>      lr : lowrec;
>   begin
>      lr.val(1) := hr.val(4);
>      lr.val(2) := hr.val(3);
>      lr.val(3) := hr.val(2);
>      lr.val(4) := hr.val(1);
>      return lowtow32 (lr);
>   end h2l32;
> begin
>   null;
> end endian;