Re: [PATCH] x86/Intel: accept mandated operand order for vcvt{,u}si2s{d,s}

["Jan Beulich" <JBeulich at suse dot com>]

>>> On 25.05.15 at 16:55, <kirill.yukhin@gmail.com> wrote:
> Folks,
> 
> On 05 May 17:07, Jan Beulich wrote:
>> >>> On 23.04.15 at 15:17, <hjl.tools@gmail.com> wrote:
>> > On Thu, Apr 23, 2015 at 6:06 AM, Jan Beulich <JBeulich@suse.com> wrote:
>> >>>>> On 23.04.15 at 14:39, <hjl.tools@gmail.com> wrote:
>> >>> On Thu, Apr 16, 2015 at 7:16 AM, Jan Beulich <JBeulich@suse.com> wrote:
>> >>>> As pointed out before, the documentation mandates the rounding mode to
>> >>>> follow the GPR, so gas should accept such input. As the brojen code got
>> >>>> released already we sadly will need to continue to also accept the
>> >>>> badly ordered operands.
>> >>>>
>> >>>> gas/testsuite/
>> >>>> 2015-04-16  Jan Beulich  <jbeulich@suse.com>
>> >>>>
>> >>>>         * gas/i386/avx512f-intel.d: Adjust expectations on operand order.
>> >>>>         * gas/i386/evex-lig256-intel.d: Likewise.
>> >>>>         * gas/i386/evex-lig512-intel.d: Likewise.
>> >>>>         * gas/i386/x86-64-avx512f-intel.d: Likewise.
>> >>>>         * gas/i386/x86-64-evex-lig256-intel.d: Likewise.
>> >>>>         * gas/i386/x86-64-evex-lig512-intel.d: Likewise.
>> >>>>
>> >>>> opcodes/
>> >>>> 2015-04-16  Jan Beulich  <jbeulich@suse.com>
>> >>>>
>> >>>>         * i386-opc.tbl: New IntelSyntax entries for vcvt{,u}si2s{d,s}.
>> >>>>         * i386-tbl.h: Regenerate.
>> >>>>
>> >>>
>> >>> I checked with our people.   Intel Software Developer Manual only governs
>> >>> the output side of the binary form of instruction byte stream matches what
>> >>> HW expect. Each assembly tool product has its own implementation of
>> >>> transforming the input language/dialect into the output stream.  In case of
>> >>> GNU assembler, operand order for AT&T and Intel syntax for AVX512 is
>> >>> the one used in AVX512 testcases.
>> >>
>> >> I don't mind AT&T being broken here (and elsewhere when it
>> >> comes to multiple source operands, as pointed out before), but
>> >> I do care about Intel syntax being in line with what the Intel
>> >> SDM says (and what I assume MASM is [going to] use). So
>> >> unless you're trying to tell me that the SDM is going to be
>> >> changed, or you have proof that MASM also deviates from what
>> >> the current documentation mandates ...
>> > 
>> >>> It is not OK.
>> >>
>> >> ... I guess as the Intel syntax maintainer I could decide to ignore
>> >> this.
>> > 
>> > MASM AVX512 compatibility isn't our goal.  Compatible with NASM is
>> > a good ideal.  Peter, Kirill, let's work it out.
>> > 
>> > Adding Peter for NASM and Kirill for GAS.
>> 
>> Not having seen any response from them at all, I think applying
>> at least the assembler side (which leaves the current bogus
>> operand order available) should really not be controversial. As
>> to the disassembler side, I continue to think that Intel syntax
>> disassembly should preferably match the Intel manual, especially
>> when there is no other implementation to use as reference.
>> 
>> Thoughts?
> Wanted to mention couple of points:
>   1. I agree w/ HJ: SDM is not a source of syntax
>   2. We have two product already released: ICC (2 version at the moment) and 
> GCC
>   (4.9 and 5) which use existing syntax for emitting those insns
> 
> Said that, I don't see any reason to introduce (not replace) alternative 
> operand order.

I'm confused - did you perhaps mean to say "I don't see any reason
not to introduce ..."?

Jan