How to call __wfi on RTEMS?

HI, ALL!

RTEMS is a RTOS. I want to make it enter stop mode like below code

if(PWR_STOPEntry == PWR_STOPEntry_WFI)

 {  

   /* Request Wait For Interrupt */

   __WFI();

 }

 else

 {

   /* Request Wait For Event */

   __WFE();

 }

so i have to call __wfi like under rtems by C