How to call a C function from an assembly file (.s file)?

 Hello,

We are using Code Composer Studio Version: 5.1.0.09000.

The controller we are using is LMS35B91 and the compiler details can be found in the screen shot below.

The start up file we are using is the asm file,  bl_startup_ccs.s.

The fault ISR handler in the startup file is shown below:

;;*****************************************************************************
;;
;; The hard fault handler.
;;
;;*****************************************************************************
    .thumbfunc FaultISR
    FaultISR: .asmfunc
    ;;
    ;; Loop forever since there is nothing that we can do about a hard fault.
    ;;
    b       FaultISR
    .endasmfunc

We need to provide an LED indication from the FaultISR when the controller triggers a fault ISR due to exception.

I would like to know how to call the GPIO API (ROM_GPIOPinWrite()) from the start up file.

Note:

The GPIO API is a part of StellarisWare Peripheral Driver Library.

Reference:

http://www.element14.com/community/servlet/JiveServlet/previewBody/35057-102-1-216369/Texas%20Instruments-Stellaris-LM3S5791-Learning%20Centre%20MCU-User%20Manuals-Texas_Instruments.User_Guide_1.pdf

section: 10.2.1.29

Can anyone please guide me how to implement this?

In case if the library function is not possible to call from the asm file, kindly provide the procedure for accessing the normal c function.

Any proposals are very welcome

Thanks in Advance.

 Regards,

Suraj