Re: [PATCH v4 44/47] target/ppc: Implement xvcvbf16spn and xvcvspbf16 instructions

[Richard Henderson]

On 2/22/22 04:36, matheus.ferst@eldorado.org.br wrote:
> From: Víctor Colombo <victor.colombo@eldorado.org.br>
>
> Signed-off-by: Víctor Colombo <victor.colombo@eldorado.org.br>
> Signed-off-by: Matheus Ferst <matheus.ferst@eldorado.org.br>
> ---
>   target/ppc/fpu_helper.c             | 21 +++++++++++++++++++
>   target/ppc/helper.h                 |  1 +
>   target/ppc/insn32.decode            | 11 +++++++---
>   target/ppc/translate/vsx-impl.c.inc | 31 ++++++++++++++++++++++++++++-
>   4 files changed, 60 insertions(+), 4 deletions(-)
>
> diff --git a/target/ppc/fpu_helper.c b/target/ppc/fpu_helper.c
> index 7773333bd7..d77900fff1 100644
> --- a/target/ppc/fpu_helper.c
> +++ b/target/ppc/fpu_helper.c
> @@ -2790,6 +2790,27 @@ VSX_CVT_FP_TO_FP_HP(xscvhpdp, 1, float16, float64, 
> VsrH(3), VsrD(0), 1)
>   VSX_CVT_FP_TO_FP_HP(xvcvsphp, 4, float32, float16, VsrW(i), VsrH(2 * i  + 1), 
> 0)
>   VSX_CVT_FP_TO_FP_HP(xvcvhpsp, 4, float16, float32, VsrH(2 * i + 1), VsrW(i), 
> 0)
>   
> +void helper_XVCVSPBF16(CPUPPCState *env, ppc_vsr_t *xt, ppc_vsr_t *xb)
> +{
> +    ppc_vsr_t t = { };
> +    int i;
> +
> +    helper_reset_fpstatus(env);
> +    for (i = 0; i < 4; i++) {
> +        if (unlikely(float32_is_signaling_nan(xb->VsrW(i), &env->fp_status))) {
> +            float_invalid_op_vxsnan(env, GETPC());
> +            t.VsrH(2 * i + 1) = float32_to_bfloat16(
> +                float32_snan_to_qnan(xb->VsrW(i)), &env->fp_status);
> +        } else {
> +            t.VsrH(2 * i + 1) =
> +                float32_to_bfloat16(xb->VsrW(i), &env->fp_status);
> +        }
> +    }

Do not check for snan first; use float_flag_invalid_snan.
And you can move that check outside the loop, before the
writeback of t to *xt.


r~