[PATCH v2] X86: disambiguate unqualified btr, bts

[Tim Northover]

On Wed, Jul 17, 2013 at 4:54 PM, James Molloy <james at jamesmolloy.co.uk> wrote:
> Wouldn't this be a viable use of the third disassembler return value
> "SoftFail"? The only difference between its use here and how it is used in
> the ARM backend is that the Intel manuals explicitly define the behaviour in
> the out of range case, but you could easily reappropriate SoftFail for the
> x86 architecture to mean "It's defined, but I'm going to warn about it".

I think that's going too far; these instructions appear to be
sanctioned in the manual unlike the ARM ones. But there's a
CommentStream available during disassembly. They could probably be
annotated as "non-standard encoding ..." or something more pithy if we
decide to go down that route.

I think this is the approach armasm takes to at least some of the
similar ARM issues.

Tim.