Re: [PATCH][ARM][gas] Make gas accept vcmp[e].f{32,64} <reg>, #0.0

[Kyrill Tkachov <kyrylo dot tkachov at arm dot com>]

Ping.
https://sourceware.org/ml/binutils/2014-08/msg00058.html

Thanks,
Kyrill

On 07/08/14 09:54, Will Newton wrote:
> On 7 August 2014 09:45, Kyrill Tkachov <kyrylo.tkachov@arm.com> wrote:
> > On 05/08/14 15:14, Will Newton wrote:
> > > On 5 August 2014 14:11, Kyrill Tkachov <kyrylo.tkachov@arm.com> wrote:
> > > > On 04/08/14 11:08, Will Newton wrote:
> > > > > On 4 August 2014 10:34, Kyrill Tkachov <kyrylo.tkachov@arm.com> wrote:
> > > > >
> > > > > Hi Kyrill,
> > > > >
> > > > > > The ARM ARM says that the VFP compare with zero instructions (vcmp,
> > > > > > vcmpe)
> > > > > > accept the zero in the form of a #0.0 immediate. However, gas currently
> > > > > > only
> > > > > > accepts #0. This patch fixes that and some simple tests are added.
> > > > > >
> > > > > > The new parse_ifimm_zerofunction is rather simple and is modelled on
> > > > > > the
> > > > > > parse_qfloat_immediate below it and didn't blow up in my testing.
> > > > > >
> > > > > >
> > > > > > make check on gas passes and a gcc testsuite run doesn't show any
> > > > > > problems.
> > > > > >
> > > > > > Ok for trunk?
> > > > > >
> > > > > > Thanks,
> > > > > > Kyrill
> > > > > >
> > > > > > [gas/]
> > > > > > 2014-06-24  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
> > > > > >
> > > > > >        * config/tc-arm.c (parse_ifimm_zero): New function.
> > > > > >        (enum operand_parse_code): Add OP_RSVD_FI0 value.
> > > > > >        (parse_operands): Handle OP_RSVD_FI0.
> > > > > >        (asm_opcode_insns): Use RSVD_FI0 for second operand of vcmp,
> > > > > > vcmpe.
> > > > > >
> > > > > > [gas/testsuite/]
> > > > > > 2014-06-24  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
> > > > > >
> > > > > >        * gas/arm/ual-vcmp.s: New file.
> > > > > >        * gas/arm/ual-vcmp.d: Likewise.
> > > > > Would it be possible to use my_get_expression or a similar parser for
> > > > > this?
> > > > Hi Will,
> > > >
> > > > Thanks for the suggestion, but I'm struggling to figure out what
> > > > my_get_expression is supposed to be doing. Is it supposed to be taking a
> > > > string and parsing it into an expressionS?
> > > > I'm not very well versed in gas internal data types...
> > > Yes, that's pretty much it. I think an integer will be type O_constant
> > > with the value in X_add_number and a floating point value O_big with a
> > > value in generic_floating_point_number. The expr.c code is not pretty
> > > but it should be possible to make it do something approaching what's
> > > reguired...
> >
> > Hi Will,
> >
> > After a bit of investigation, it seems that atof_generic is what I need. It
> > can handle any form of floating point zero, as well as plain old "0".
> >
> >  From what I understand from looking around gas the global variable
> > generic_floating_point_number is supposed to be used to store the various
> > parts of a floating point representation and the way it's checked for 0.0 in
> > config/atof-ieee.c is by comparing the .low and .leader components.
> >
> >   I've also added a *-bad.s testcase to make sure we reject non-zero
> > immediates.
> >
> > make check on gas passes.
> >
> > How does this look?
> Looks good to me (although I am not a maintainer).
>
> > Thanks,
> > Kyrill
> >
> > [gas/]
> > 2014-08-07  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
> >
> >
> >          * config/tc-arm.c (parse_ifimm_zero): New function.
> >          (enum operand_parse_code): Add OP_RSVD_FI0 value.
> >          (parse_operands): Handle OP_RSVD_FI0.
> >          (asm_opcode_insns): Use RSVD_FI0 for second operand of vcmp, vcmpe.
> >
> > [gas/testsuite/]
> > 2014-08-07  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
> >
> >
> >          * gas/arm/ual-vcmp.s: New file.
> >          * gas/arm/ual-vcmp.d: Likewise.
> >          * gas/arm/vcmp-zero-bad.s: Likewise.
> >          * gas/arm/vcmp-zero-bad.d: Likewise.
> >          * gas/arm/vcmp-zero-bad.l: Likewise.