Not sure if the title of my question makes sense, so bear with me. I'd like to find a system for representing single digit numbers with as few bits as possible. There is a method called "Densely packed decimal" (https://en.wikipedia.org/wiki/Densely_packed_decimal) which would be my ideal solution, but I wouldn't even know if that's possible or how I could implement it without further research or guidance from a guru.
The next best thing would be to be able to use a 4-bit addressing system to represent digits, but once again I'm not sure if that is even possible.
So! Barring implementations of the above methods/systems, I could settle for a 1-byte data type which I could use to represent pairs of two integers. Is there a 1-byte data-type in Fortran, or does it not allow for that level of control?