Hello to the Keil Software Discussion Forum: My name is Randy Norris and I am with NORgate Engineering & Associates. We are considering using the 8051 for an online signal processing application and our question is this: Does the Keil 8051 C compiler have the capability to use arithmetic functions such as sin, cos, log, sqrt, etc? Our guess is that the answer is yes, and a statement at the beginning of the code like #include <math.h> would be required. However,this is only an educated guess. We have an evaluation version of Keil software from 2 years ago, and the User's Guide 11.97, but this documentation does not address our question. Thanks for your help. Randy Norris