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Re: S390: Allowing a NOP instruction without operands

From: Nick Clifton <nickc at redhat dot com>
To: Martin Schwidefsky <schwidefsky at de dot ibm dot com>
Cc: binutils at sourceware dot org, Andreas Krebbel <Andreas dot Krebbel at de dot ibm dot com>
Date: Thu, 18 Jun 2009 11:10:42 +0100
Subject: Re: S390: Allowing a NOP instruction without operands
References: <m3d492kfko.fsf@redhat.com> <20090618111914.496fb4d1@skybase>

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

Follow-Ups:
- Re: S390: Allowing a NOP instruction without operands
  - From: Martin Schwidefsky

References:
- S390: Allowing a NOP instruction without operands
  - From: Nick Clifton
- Re: S390: Allowing a NOP instruction without operands
  - From: Martin Schwidefsky

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