Re: [PATCH 11/12] target/loongarch: Use generic hrev64_i32() in REVB.2H opcode

[Richard Henderson]

On 8/22/23 09:11, Philippe Mathieu-Daudé wrote:
> > > -static void gen_revb_2h(TCGv dest, TCGv src1)
> > > -{
> > > -    TCGv mask = tcg_constant_tl(0x00FF00FF);
> > > -    TCGv t0 = tcg_temp_new();
> > > -    TCGv t1 = tcg_temp_new();
> > > -
> > > -    tcg_gen_shri_tl(t0, src1, 8);
> > > -    tcg_gen_and_tl(t0, t0, mask);
> > > -    tcg_gen_and_tl(t1, src1, mask);
> > > -    tcg_gen_shli_tl(t1, t1, 8);
>
> Looking at 
> https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html#_revb_2h4h2wd
> the sign extension is missing, so the next line:
>
> > > -    tcg_gen_or_tl(dest, t0, t1);
>
> should be replaced by smth like:
>
>          tcg_gen_or_tl(t0, t0, t1);
>          tcg_gen_ext32s_tl(dest, t0);

Extension is handled by

TRANS(revb_2h, gen_rr, EXT_NONE, EXT_SIGN, gen_revb_2h)
                                 ^^^^^^^^^
this


r~