How to dump D-cache

Hi,

The instruction dcread is used to read data cache. The syntax is
dcread RT,RA,RB. The effective address is formed by adding RA to RB.
In order to read a specific cache line or the whole d-cache, how do I
know the effective addresses correponding to the cache line(s)? The
processor is ppc440.

Thanks,
-Shawn.