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Re: Universality of nop
- From: Hans-Peter Nilsson <hp at bitrange dot com>
- To: Joel Sherrill <joel dot sherrill at oarcorp dot com>
- Cc: "binutils at sourceware dot org" <binutils at sourceware dot org>, Christian Svensson <christian at cmd dot nu>, Hesham Moustafa <heshamelmatary at gmail dot com>
- Date: Wed, 20 Aug 2014 18:13:49 -0400 (EDT)
- Subject: Re: Universality of nop
- Authentication-results: sourceware.org; auth=none
- References: <53F4F786 dot 1010809 at oarcorp dot com>
On Wed, 20 Aug 2014, Joel Sherrill wrote:
> In getting RTEMS and tests to build for the or1k, Hesham ran into
> test which had inline assembly for "nop". or1k does not have nop
> defined. Interestingly, this has not been a problem on the 17 other
> architectures we build RTEMS for.
> Should all targets have a nop instruction?
No, binutils-hackers don't have (should not claim) that say.
If you want to provide a mostly-universal pseudo-op ".nop",
that'd be fine (mostly, as the target environment should have
first say about its semantics - it may have claimed that
pseudo-op), but introducing an actual universal instruction with
certain semantics is unacceptable.
> Or did we just get lucky
> 17 times? :)