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From: "Tarjei T. Jensen" <tarjei.jensen@kvaerner.com>
Newsgroups: comp.lang.ada
Subject: Re: RISC
Date: Thu, 15 Mar 2001 14:03:09 +0100
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Date: 2001-03-15T14:03:09+01:00
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chris.danx wrote in message ...
>I'm curious about 'mod' types.  If i define a type 'byte' like so
>
>*    type byte is mod 256;
>
>will it occupy one byte of memory.
>
>
>similarly if i define
>
>*    type word is mod 65536
>
>will it occupy two bytes.


You need to add
for byte'size use 8;
for word'size use 16;
if you use arrays or records it can be a good idea to use pragma(pack);

>As i was writing i suddenly realised i got a problem with little/big
>endian-ness.  I'm writing files on an Athlon(so it's x86) which is little(i
>think).  If i port to a M68000 say, which is big endian (again i'm unsure),
>what should i do to convert the 'bytecode' file.  I dunno what to do with
>this.  I do plan to port to other platforms in the future so this is
>important.  Is it true that all networks use big endian?  Anyway this is
for
>the future, just thought i'd ask in case i need to plan ahead for this.

The IP protocol tends to be big endian. However don't let that keep you from
creating a little endian risc machine.

You can probably select endianness with the bit_order attribute. You can
choose between 'bit_order=low_order_first or high_order_first. Or you can
read and write the program one byte at a time.

Greetings,