This is the mail archive of the
binutils@sources.redhat.com
mailing list for the binutils project.
Re: GAS for ARM: Reject ASR/LSR/ROR with immediate of 0
- To: Nick Clifton <nickc at redhat dot com>
- Subject: Re: GAS for ARM: Reject ASR/LSR/ROR with immediate of 0
- From: Richard Earnshaw <rearnsha at arm dot com>
- Date: Thu, 17 Aug 2000 10:31:06 +0100
- Cc: scottb at netwinder dot org, phillpB at cygnus dot com, binutils at sources dot redhat dot com
- Cc: rearnsha at arm dot com
- Organization: ARM Ltd.
- Reply-To: rearnsha at arm dot com
nickc@redhat.com said:
> Agreed. In fact I decided to tidy up that whole code area (see the
> patch below). One thing I did add was a warning message if "ROR #0"
> is used, since this is turned into RRX, which may not have been what
> the programmer was expecting.
> If anyone has any problems with this patch (which I am about to check
> in), please let me know.
This is great except for converting ror #0 into rrx. That is just plain
wrong.
In the past we converted any shift or rotate of 0 into asl #0 (which is
the encoding of no shift at all); while it might be considered dubious,
it was basically the same operation as was requested. But ror #0 is
definitely not the same as rrx.
I think we should continue to convert any shift or rotate of 0 into "asl
#0"; though perhaps we should emit a warning that that is what is being
done.
Richard.