Re: opcodes

[Raghavendra Rao <jp.raghavendra@india.sun.com>]

Julian,

> 
> -regular commands  00-0f
> -regular reponses 40 - 4f
> -one way 10-1f/50-5f
> etc.
> 
> I am open to suggestions.
> 

For simplicity it would work best to have them fall in a range for easier
lookup, but it would also work better if each bit in the upper nibble of
the opcode denotes the following:

	solicited
	unsolicited
	command
	response

while the lower nibble describes the real code.

With the above, since commands are always unsolicited, denoting them so
with 2 bits (unsolicited bit as well as command bit) appears a little
redundant. However, to fully qualify a response, we need either the 
solicited or the unsolicited bits to be true.

In any case, a bit layout for opcode field is desired.

Thanks.
-JP