[net.micro.68k] Warning: Don"t use the "clr" instruction on device registers

mem (03/11/83)

c
Re: not using the CLR instruction on device registers.  True.  Also
don't use the CLR instruction, or Scc, on memory which has parity 
checking because of the read-before-write problem.

Relatedly, you'll notice that the manual says that MOVEM (move multiple)
does an extra bus cycle.  This ALSO loses if you're pushing registers
into uninitialized memory which has parity (or other error) checking.

Mark Mallett