On Tue, 15 Jan 2002, Lloyd Parkes wrote:

> I have been reading through the MPC601 manual and some PowerPC manuals,
> and I can't see much standing in the way of NetBSD on the 601. The only
> changes that I spotted were in some bit definitions in the MMU.
>
> Am I missing something, or is that the only thing preventing NetBSD from
> being ported to 601 based machines.

There are a number of PPC instructions which aren't implimented. According
to my 601 manual (MPC601UM/AD Rev 1), they are:

32-bit:
fres, frsqrtefsel, fsqrt, fsqrts, mfspr(*), mftb, mtspr(*), stfiwx, tlbia,
tlbsync.

(*) some of the spr's are different. Mainly the BAT ones and TB & TBU.

tlbia and tlbsync are supervisor instructions, so we don't need to emulate
them.

There are also a number of 64-bit ppc instructions not implimented, but I
think they would cause exceptions now, so we don't need to emulate them.

Take care,

Bill