Re: [PATCH v4 38/47] target/ppc: Refactor VSX_SCALAR_CMP_DP

[Richard Henderson]

On 2/22/22 04:36, matheus.ferst@eldorado.org.br wrote:
> From: Víctor Colombo <victor.colombo@eldorado.org.br>
>
> Refactor VSX_SCALAR_CMP_DP, changing its name to VSX_SCALAR_CMP and
> prepare the helper to be used for quadword comparisons.
>
> 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 | 31 ++++++++++++++-----------------
>   1 file changed, 14 insertions(+), 17 deletions(-)
>
> diff --git a/target/ppc/fpu_helper.c b/target/ppc/fpu_helper.c
> index 9b034d1fe4..5ebbcfe3b7 100644
> --- a/target/ppc/fpu_helper.c
> +++ b/target/ppc/fpu_helper.c
> @@ -2265,28 +2265,30 @@ VSX_MADDQ(XSNMSUBQP, NMSUB_FLGS, 0)
>   VSX_MADDQ(XSNMSUBQPO, NMSUB_FLGS, 0)
>   
>   /*
> - * VSX_SCALAR_CMP_DP - VSX scalar floating point compare double precision
> + * VSX_SCALAR_CMP - VSX scalar floating point compare
>    *   op    - instruction mnemonic
> + *   tp    - type
>    *   cmp   - comparison operation
>    *   exp   - expected result of comparison
> + *   fld   - vsr_t field
>    *   svxvc - set VXVC bit
>    */
> -#define VSX_SCALAR_CMP_DP(op, cmp, exp, svxvc)                                \
> +#define VSX_SCALAR_CMP(op, tp, cmp, fld, exp, svxvc)                          \
>   void helper_##op(CPUPPCState *env, ppc_vsr_t *xt,                             
> \
>                    ppc_vsr_t *xa, ppc_vsr_t *xb)                                
> \
>   {                                                                             
> \
> -    ppc_vsr_t t = *xt;                                                        \
> +    ppc_vsr_t t = { };                                                        \
>       bool vxsnan_flag = false, vxvc_flag = false, vex_flag = false;            
> \
>                                                                                 
> \
> -    if (float64_is_signaling_nan(xa->VsrD(0), &env->fp_status) ||             \
> -        float64_is_signaling_nan(xb->VsrD(0), &env->fp_status)) {             \
> +    if (tp##_is_signaling_nan(xa->fld, &env->fp_status) ||                    \
> +        tp##_is_signaling_nan(xb->fld, &env->fp_status)) {                    \
>           vxsnan_flag = true;                                                   
> \
>           if (fpscr_ve == 0 && svxvc) {                                         
> \
>               vxvc_flag = true;                                                 
> \
>           }                                                                     
> \
>       } else if (svxvc) {                                                       
> \
> -        vxvc_flag = float64_is_quiet_nan(xa->VsrD(0), &env->fp_status) ||     \
> -            float64_is_quiet_nan(xb->VsrD(0), &env->fp_status);               \
> +        vxvc_flag = tp##_is_quiet_nan(xa->fld, &env->fp_status) ||            \
> +            tp##_is_quiet_nan(xb->fld, &env->fp_status);                      \
>       }                     

Note that this can be simplified further, using the full FloatRelation result and 
float_flag_invalid_snan.

Note that do_scalar_cmp gets half-way there, only checking for NaNs once we have 
float_relation_unordered as a comparision result.  But it could go further and check 
float_flag_invalid_snan and drop all of the other checks vs snan and qnan.


r~