How do i include C function in an A.51 file?

"Is there any references on how should i call C functions from ASM?"

Although it is more common to call ASM routines from C than vice versa, just make sure you abide by all the interfacing and register usage conventions:

http://www.keil.com/support/man/docs/c51/c51_ap_ctoasm.htm

"Is there any references on how should i call C functions from ASM?"

Although it is more common to call ASM routines from C than vice versa, just make sure you abide by all the interfacing and register usage conventions:

http://www.keil.com/support/man/docs/c51/c51_ap_ctoasm.htm