Suggested by Ingo in ticket #6139. Code is adapted from x86.
Note that on ppc64 GPR1 needs to be 64-bit, thus the choice of addr_t.
Resolves part of ticket #6160.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@37281 a95241bf-73f2-0310-859d-f6bbb57e9c96