data types & efficiency

["Davide" <ppp@ppp.it>]

hello everybody,

speaking in general, if I have a *XX-bit* architecture for which I'm
developing software in Ada, and I need to declare some *scalar* (not records
nor arrays etc.) variable eg. integer: what should be better to do:

1) always declare that variable as the *smallest* data type that will hold
the highest value of its possible range (example: if it can assume values
from 0 to 150 then declare it as an 8-bit integer);

2) tend to declare the variable as the machine "native" data type,  i.e.
XX-bit represented.

I think considerations should be made about efficiency and memory occupation
*but* (maybe) taking into account memory alignment (that could vanify
considerations made at point 1...maybe).

Waiting for your opinions,

thanks in advance.