How to access IO registers on ADSP 21992 using C language?

How can I access IO register on 21992 using C language?

For example, if I want to write PWM0_TM, i can do this with Assemble language like this:

IOPG=PWM0_Page; // page of PWM0 block ar = PWM_Period; IO(PWM0_TM)= ar; //write to PWM period register

But how can I do this with C language? I can not figure out how to set the memory address for such IO registers.

Thanks.

thanks.