On 3/7/23 15:34, Richard Henderson wrote:
> Compute both partial results separately and accumulate
> at the end, instead of accumulating in the middle.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
> Cc: Daniel Henrique Barboza <danielhb413@gmail.com>
> Cc: Cédric Le Goater <clg@kaod.org>
> Cc: David Gibson <david@gibson.dropbear.id.au>
> Cc: Greg Kurz <groug@kaod.org>
> Cc: qemu-ppc@nongnu.org
> ---
> target/ppc/translate/vmx-impl.c.inc | 21 +++++++++++----------
> 1 file changed, 11 insertions(+), 10 deletions(-)
>
> diff --git a/target/ppc/translate/vmx-impl.c.inc b/target/ppc/translate/vmx-impl.c.inc
> index 7af6d7217d..ca27c11d87 100644
> --- a/target/ppc/translate/vmx-impl.c.inc
> +++ b/target/ppc/translate/vmx-impl.c.inc
> @@ -2236,24 +2236,25 @@ static bool trans_MTVSRBMI(DisasContext *ctx, arg_DX_b *a)
>
> static bool do_vcntmb(DisasContext *ctx, arg_VX_mp *a, int vece)
> {
> - TCGv_i64 rt, vrb, mask;
> - rt = tcg_const_i64(0);
> - vrb = tcg_temp_new_i64();
> + TCGv_i64 r[2], mask;
> +
> + r[0] = tcg_temp_new_i64();
> + r[1] = tcg_temp_new_i64();
> mask = tcg_constant_i64(dup_const(vece, 1ULL << ((8 << vece) - 1)));
>
> for (int i = 0; i < 2; i++) {
> - get_avr64(vrb, a->vrb, i);
> + get_avr64(r[i], a->vrb, i);
> if (a->mp) {
> - tcg_gen_and_i64(vrb, mask, vrb);
> + tcg_gen_and_i64(r[i], mask, r[i]);
> } else {
> - tcg_gen_andc_i64(vrb, mask, vrb);
> + tcg_gen_andc_i64(r[i], mask, r[i]);
> }
> - tcg_gen_ctpop_i64(vrb, vrb);
> - tcg_gen_add_i64(rt, rt, vrb);
> + tcg_gen_ctpop_i64(r[i], r[i]);
> }
>
> - tcg_gen_shli_i64(rt, rt, TARGET_LONG_BITS - 8 + vece);
> - tcg_gen_trunc_i64_tl(cpu_gpr[a->rt], rt);
> + tcg_gen_add_i64(r[0], r[0], r[1]);
> + tcg_gen_shli_i64(r[0], r[0], TARGET_LONG_BITS - 8 + vece);
> + tcg_gen_trunc_i64_tl(cpu_gpr[a->rt], r[0]);
> return true;
> }
>