Re: target/ppc: Move VMX int add/sub saturate insns to decodetree.

[Chinmay Rath]

Hi Richard,

On 5/12/24 15:59, Richard Henderson wrote:
> On 5/12/24 11:38, Chinmay Rath wrote:
> > 1. vsubsbs and bcdtrunc :
> >
> > In this pair, bcdtrunc has the insn flag check PPC2_ISA300 in the
> > vmx-impl file, within the GEN_VXFORM_DUAL macro, which does this flag
> > check.
> > However it also has this flag check in the vmx-ops file.
> > Hence I have retained the same in the new entry in the vmx-ops file.
> > This is consistent with the behaviour in done in the following commit :
> > https://github.com/qemu/qemu/commit/b132be53a4ba6a0a40d5643d791822f958a36e53 
> >
> > So even though the flag check is removed from the vmx-impl file, it is
> > retained in the vmx-ops file. All good here.
> >
> > 2. vadduhs and vmul10euq :
> >
> > In this pair, vmul10euq has the insn flag check PPC2_ISA300 in the
> > vmx-impl file, check done within the GEN_VXFORM_DUAL macro.
> > However the same flag was NOT originally present in the
> > vmx-ops file, so I have NOT included in its new entry in the vmx-ops
> > file. I have done this, following the behaviour done in the following
> > commit :
> > https://github.com/qemu/qemu/commit/c85929b2ddf6bbad737635c9b85213007ec043af 
> >
> > So this flag check for vmul10euq is excluded now. Is this not a 
> > problem ?
> > I feel that this leads to the flag check being skipped now, however this
> > behaviour was followed in the above mentioned commit.
>
> This second link is for VAVG* and VABSD*.
>
> Yes you are correct that this second case was done incorrectly. 
> Thankfully the mistake was fixed in the very next commit, when VABSD* 
> was converted to decodetree as well.
Thank you very much for the clarification !
> r~
Regards,
Chinmay