Re: Does Ada support endiannes?

[Niklas Holsti <niklas.holsti@tidorum.invalid>]

On 11-12-12 10:57 , Gerd wrote:
> Hello,
>
> a while ago, I worked at Siemens company, with a (CHILL-)compiler that
> supports endianess similar to this:
>
> litte : Integer; pragma Datalayout(Little_Endian);
> big  : Integer; pragma Dtalayout(Big_Endian);
>
> little := big; -- compiler generates code for converting big endian to
> little endian
>
> if little = big -- compiler converts the variables to machines nativ
> format before testing
>
>
> Is there something similar available with Ada?

No.

> Or has someone any suggestions how to rewrite it in ada?

Assuming that the native format is big-endian, you could define a new type:

    type Little_Endian_Integer is record ... end record;

and write representation specifications to lay out the components of the 
type in a little-endian way. But you would then have write your own 
implementations of all arithmetic operations on Little_Endian_Integer, 
for example the "+" operator, including forms that mix types, for 
example for Integer + Little_Endian_Integer.

In practice, it would be much easier to write only two conversion 
functions, to convert to and from the non-native endianness, and call 
those functions only at the start and end of a computation to load and 
store the variables that use the non-native endianness.

-- 
Niklas Holsti
Tidorum Ltd
niklas holsti tidorum fi
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