I am using GCC for V850. It isn't 8051 derivative :) Oh... Andy... don't tell me, please, that this forum for 8051 ONLY!!!!

So, As I'v found it works realy good - now my compiled project is something like ~100 Kb. And no compiler bugs found ;) So, I do not use standart librarys, because they use a lot of RAM. It is not problem ROM for me, but I have to save RAM space...

Yep. Your idea about double instead of float, may be realy good. I can use it inside, and later convert to float. Thanks Alfredo!