Re: [PATCH v2 09/22] target/loongarch: Add fixed point bit instruction translation

[Richard Henderson]

On 7/26/21 2:22 AM, Song Gao wrote:
> Hi, Richard.
>
> On 07/23/2021 09:29 AM, Richard Henderson wrote:
> > On 7/20/21 11:53 PM, Song Gao wrote:
> > > This patch implement fixed point bit instruction translation.
> > >
> > > This includes:
> > > - EXT.W.{B/H}
> > > - CL{O/Z}.{W/D}, CT{O/Z}.{W/D}
> > > - BYTEPICK.{W/D}
> > > - REVB.{2H/4H/2W/D}
> > > - REVH.{2W/D}
> > > - BITREV.{4B/8B}, BITREV.{W/D}
> > > - BSTRINS.{W/D}, BSTRPICK.{W/D}
> > > - MASKEQZ, MASKNEZ
> > >
> > > Signed-off-by: Song Gao <gaosong@loongson.cn>
> > > ---
> > >    target/loongarch/helper.h     |  10 +
> > >    target/loongarch/insns.decode |  45 +++
> > >    target/loongarch/op_helper.c  | 119 ++++++++
> > >    target/loongarch/trans.inc.c  | 665 
> > > ++++++++++++++++++++++++++++++++++++++++++
> > >    4 files changed, 839 insertions(+)
> > >
> > > diff --git a/target/loongarch/helper.h b/target/loongarch/helper.h
> > > index 6c7e19b..bbbcc26 100644
> > > --- a/target/loongarch/helper.h
> > > +++ b/target/loongarch/helper.h
> > > @@ -8,3 +8,13 @@
> > >      DEF_HELPER_3(raise_exception_err, noreturn, env, i32, int)
> > >    DEF_HELPER_2(raise_exception, noreturn, env, i32)
> > > +
> > > +DEF_HELPER_2(cto_w, tl, env, tl)
> > > +DEF_HELPER_2(ctz_w, tl, env, tl)
> > > +DEF_HELPER_2(cto_d, tl, env, tl)
> > > +DEF_HELPER_2(ctz_d, tl, env, tl)
> >
> > The count leading and trailing zero operations are built into tcg.  Count 
> > leading and trailing one simply needs a NOT operation to convert it to zero.
>
> My understanding is this：
>     
>    cto -> NOT operation (tcg_gen_not_tl)  -> ctz,
>
>    is right?

Yes.


r~