CCS/TMS320C6657: How can I get "system time" using SYS/BIOS?

Tool/software: Code Composer Studio

How can I get the system time using SYS/BIOS?  

I have defined a C structure (below) and I would like to fill the structure with the system time. Thanks

struct timeval {
long tv_sec; /* seconds */
long tv_usec; /* and microseconds */
};