Improve precision of float numbers

[deetee]

Thanks for the lot of hints.

My next calculator has an OLED display (128x64), a small (16 keys) keyboard with a fast menu function.
The MCU is a ATMEGA32 (Arduino) which offers 28k (with USB) or 32k of flash memory. Till now I tried ATTIN85 projects but 8k is a too hard limit for RPN calculators with a broad spectre of funcionalities.

A first try of BigNumbers - which is an excellent library - cost me approx. 8k (for basic math). This seems to much for my ressources. I think that is similar to the char array suggestion of Druzyek.

But the newRPL decimal library gives hope. Unfortunately I don't know how to extract this library from the 19MB-exe-file and how to involve it to my C-program (Arduino IDE). As I like "all in one source code files" it would be ideally for me to invoke C-subprograms. Sorry for my inflexibility and less experience.

Regards
deetee