TPU3 Byte Access

[jci]

In older Motorola processors (e.g., CPU32X), a byte access to the TPU module
was not allowed, however, with the PowerPC it seems to be allowed (my
assumption since it doesn't generate an exception). Does the UIMB interface
automatically convert byte (8-bit) accesses to halfword (16-bit) or word
(32-bit) thus preventing the exception?

Do you know of any Motorola documentation that addresses this issue
specifically?

Thanks.

[Andy Sinclair]

All the motorola documentation states that byte accesses are not
permitted, as does the TPU microcoding guide.

I've just tried it out and byte reads work correctly, for both odd and
even addresses.
A byte write erases the other part of the halfword.
E.g. writing 0x42 to an even byte address will result in 0x4200 being
written to the halfword.

Andy