RE: [PATCH 8/8] Support APX JMPABS

["Hu, Lin1" <lin1.hu@intel.com>]

> On 19.09.2023 17:25, Cui, Lili wrote:
> > --- a/gas/config/tc-i386.c
> > +++ b/gas/config/tc-i386.c
> > @@ -3880,6 +3880,7 @@ is_any_apx_encoding (void)
> >      || i.tm.opcode_space == SPACE_EVEXMAP4
> >      || i.has_nf
> >      || i.has_zero_upper
> > +    || i.tm.mnem_off == MN_jmpabs
> >      || (i.vex.register_specifier
> >  	&& i.vex.register_specifier->reg_flags & RegRex2);  } @@ -3887,7
> > +3888,8 @@ is_any_apx_encoding (void)  static INLINE bool
> > is_any_apx_rex2_encoding (void)  {
> > -  return (i.rex2 && i.vex.length == 2) || i.rex2_encoding;
> > +  return (i.rex2 && i.vex.length == 2) || i.rex2_encoding
> > +	  || i.tm.mnem_off == MN_jmpabs;
> >  }
> 
> These are getting both too complex for my taste, when they - iirc - sit on a
> relatively common (and hence hot) path.
>

Have modified.
 
>
> > @@ -7703,7 +7705,7 @@ match_template (char mnem_suffix)
> >    if (!quiet_warnings)
> >      {
> >        if (!intel_syntax
> > -	  && (i.jumpabsolute != (t->opcode_modifier.jump ==
> JUMP_ABSOLUTE)))
> > +	  && (i.jumpabsolute != (t->opcode_modifier.jump == JUMP_ABSOLUTE)
> > +&& t->mnem_off != MN_jmpabs))
> 
> Nit: Too long line. But - does this need changing? JMPABS isn't an indirect jump.
>

Have modified. Yes, JMPABS isn't an indirect jump. But we use jmpabs like jmpabs $123. So i.jumpabsolute == false.

> 
> > --- /dev/null
> > +++ b/gas/testsuite/gas/i386/apx-mov-inval.l
> > @@ -0,0 +1,2 @@
> > +.* Assembler messages:
> > +.*:5: Error: unsupport rex2 pseudo prefix for `mov'
> 
> What is this new file doing here, entirely in isolation?
>

In the new patch structure, "mov" related changes are all eliminated (and I don't remember why they're here).

> 
> > @@ -2057,7 +2061,7 @@ static const struct dis386 dis386[] = {
> >    { "lahf",		{ XX }, 0 },
> >    /* a0 */
> >    { "mov%LB",		{ AL, Ob }, 0 },
> > -  { "mov%LS",		{ eAX, Ov }, 0 },
> > +  { "mov%LS",		{ { JMPABS_Fixup, eAX_reg }, { JMPABS_Fixup,
> v_mode } }, 0 },
> >    { "mov%LB",		{ Ob, AL }, 0 },
> >    { "mov%LS",		{ Ov, eAX }, 0 },
> >    { "movs{b|}",		{ Ybr, Xb }, 0 },
> > @@ -9690,6 +9694,15 @@ print_insn (bfd_vma pc, disassemble_info *info, int
> intel_syntax)
> >        goto out;
> >      }
> >
> > +  if (ins.jmpabs
> > +      && ((ins.prefixes & (PREFIX_OPCODE | PREFIX_ADDR)) != 0x0
> > +	  || (ins.rex2_payload & 0x8) != 0x0))
> > +    {
> > +      i386_dis_printf (info, dis_style_text, "(bad)");
> > +      ret = ins.end_codep - priv.the_buffer;
> > +      goto out;
> > +    }
> 
> Why can't this be dealt with in JMPABS_Fixup()?
>

Have modified.

BRs,
Lin