S390: Allowing a NOP instruction without operands

[Nick Clifton]

Hi Martin,

> First of all: yes I think it makes sense to have a nop instruction that
> can be used without operands. I don't like the implementation though,
> to check for particular opcodes with a strcmp feels wrong.

I thought that you might say that. :-)

> My counter
> proposal would be to introduce new variantes for the RR_0R and RX_0RRD
> instruction formats. Make all operands optional and replace the strcmp
> check with a check against S390_OPERAND_OPTIONAL.

Fine by me.  I just went with the simplest solution.  (Plus I have never 
looked at the s390 opcode generation system before and I was worried 
that if I tried to introduce a new nop pattern I would break something).

Please could you go ahead and apply your patch ?

Cheers
   Nick