At the moment I'm trying to develop a PID controller built with a 8051 microcontroller. The problem is that I don't know how to cope with the manipulation of floating point variables. I've tried using the Keil C51 compiler but I need the libraries (C51FPS.LIB, C51FPC.LIB and C51FPL.LIB, especially the first one) related to floating point arithmetic, which are not available on the evaluation software. Does anybody know where or how can I get them?

Another solution could be to implement them starting from any clues on floating-point arithmetic (multiplication, addition, etc.). Please, help me!

Thanks