How to include math operation?

[matteo.posterli at studenti.unipr.it (Matteo)]

Hi 
I would like to use some math function but the compiler says always to me ;
undefined reference.. 
so I try to add in the makefile -lm where there are specificated the LIBS like
following;

LIBS = -lm -lrtemsall -lc

but the result it's the same, How I have to do?
Someone can help me .
I have configured rtems for i386 and pc386.

Thanks in advantage 
Matteo Posterli