On Mon, 18 Feb 2019 at 14:31, David Gibson <da...@gibson.dropbear.id.au> wrote:
>
> From: Richard Henderson <richard.hender...@linaro.org>
>
> Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
> Acked-by: David Gibson <da...@gibson.dropbear.id.au>
> Message-Id: <20190215100058.20015-8-mark.cave-ayl...@ilande.co.uk>
> Signed-off-by: David Gibson <da...@gibson.dropbear.id.au>
So this is a commit from 18 months back, but I happened
to notice an oddity in it while grepping the code base for
something else:
> diff --git a/target/ppc/translate/vsx-impl.inc.c
> b/target/ppc/translate/vsx-impl.inc.c
> index 944fc0608a..0e8cecb00a 100644
> --- a/target/ppc/translate/vsx-impl.inc.c
> +++ b/target/ppc/translate/vsx-impl.inc.c
> @@ -1359,38 +1359,24 @@ static void gen_xxsel(DisasContext * ctx)
>
> static void gen_xxspltw(DisasContext *ctx)
> {
> - TCGv_i64 b, b2;
> - TCGv_i64 vsr;
> + int rt = xT(ctx->opcode);
> + int rb = xB(ctx->opcode);
> + int uim = UIM(ctx->opcode);
> + int tofs, bofs;
[...]
> - tcg_gen_shli_i64(b2, b, 32);
> - tcg_gen_or_i64(vsr, b, b2);
> - set_cpu_vsrh(xT(ctx->opcode), vsr);
> - set_cpu_vsrl(xT(ctx->opcode), vsr);
> + tofs = vsr_full_offset(rt);
> + bofs = vsr_full_offset(rb);
> + bofs += uim << MO_32;
> +#ifndef HOST_WORDS_BIG_ENDIAN
> + bofs ^= 8 | 4;
> +#endif
The ifdef is HOST_WORDS_BIGENDIAN without the
third underscore, so this XOR operation will be
done on both little and big-endian hosts.
Should the ifndef line be fixed, or is this actually
a case where the xor really should be done on all hosts
so we should drop the ifndef/endif lines?
>
> - tcg_temp_free_i64(vsr);
> - tcg_temp_free_i64(b);
> - tcg_temp_free_i64(b2);
> + tcg_gen_gvec_dup_mem(MO_32, tofs, bofs, 16, 16);
> }
thanks
-- PMM
