Re: [Qemu-devel] [PATCH 08/14] Add vmaddfp and vnmsubfp instructions

[Aurelien Jarno]

On Thu, Jan 22, 2009 at 12:44:08PM -0800, Nathan Froyd wrote:
> Do the computation in higher precision and check for invalid operation
> conditions.
> 
> Signed-off-by: Nathan Froyd <address@hidden>
> ---
>  target-ppc/helper.h    |    2 +
>  target-ppc/op_helper.c |   54 
> ++++++++++++++++++++++++++++++++++++++++++++++++
>  target-ppc/translate.c |    1 +
>  3 files changed, 57 insertions(+), 0 deletions(-)
> 
> diff --git a/target-ppc/helper.h b/target-ppc/helper.h
> index a5d1972..6f5d6a6 100644
> --- a/target-ppc/helper.h
> +++ b/target-ppc/helper.h
> @@ -236,6 +236,8 @@ DEF_HELPER_3(vaddfp, void, avr, avr, avr)
>  DEF_HELPER_3(vsubfp, void, avr, avr, avr)
>  DEF_HELPER_3(vmaxfp, void, avr, avr, avr)
>  DEF_HELPER_3(vminfp, void, avr, avr, avr)
> +DEF_HELPER_4(vmaddfp, void, avr, avr, avr, avr)
> +DEF_HELPER_4(vnmsubfp, void, avr, avr, avr, avr)
>  
>  DEF_HELPER_1(efscfsi, i32, i32)
>  DEF_HELPER_1(efscfui, i32, i32)
> diff --git a/target-ppc/op_helper.c b/target-ppc/op_helper.c
> index d952113..532a08a 100644
> --- a/target-ppc/op_helper.c
> +++ b/target-ppc/op_helper.c
> @@ -2223,6 +2223,29 @@ VCMP(gtsw, >, s32)
>  #undef VCMP_DO
>  #undef VCMP
>  
> +void helper_vmaddfp (ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b, ppc_avr_t *c)
> +{
> +    int i;
> +    for (i = 0; i < ARRAY_SIZE(r->f); i++) {
> +        HANDLE_NAN3(r->f[i], a->f[i], b->f[i], c->f[i]) {
> +            /* Need to do the computation in higher precision and round
> +             * once at the end.  */
> +            float64 af, cf;
> +            af = float32_to_float64(a->f[i], &env->vec_status);
> +            cf = float32_to_float64(c->f[i], &env->vec_status);
> +            if ((float64_is_infinity(af) && float64_is_zero(cf)) ||
> +                (float64_is_zero(af) && float64_is_infinity(cf))) {
> +                r->u32[i] = 0x7fc00000;
> +            } else {
> +                float64 t = float64_mul(af, cf, &env->vec_status);
> +                float64 bf = float32_to_float64(b->f[i], &env->vec_status);
> +                t = float64_add(t, bf, &env->vec_status);
> +                r->f[i] = float64_to_float32(t, &env->vec_status);
> +            }
> +        }
> +    }
> +}

The same way as for v{add,sub} I think the NaN part is already handled
by the softfloat code.

> +
>  void helper_vmhaddshs (ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b, ppc_avr_t 
> *c)
>  {
>      int sat = 0;
> @@ -2460,6 +2483,37 @@ VMUL(uh, u16, u32)
>  #undef VMUL_DO
>  #undef VMUL
>  
> +void helper_vnmsubfp (ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b, ppc_avr_t *c)
> +{
> +    int i;
> +    for (i = 0; i < ARRAY_SIZE(r->f); i++) {
> +        HANDLE_NAN3(r->f[i], a->f[i], b->f[i], c->f[i]) {
> +            /* Need to do the computation is higher precision and round
> +             * once at the end.  */
> +            float64 af, cf;
> +            af = float32_to_float64(a->f[i], &env->vec_status);
> +            cf = float32_to_float64(c->f[i], &env->vec_status);
> +            if ((float64_is_infinity(af) && float64_is_zero(cf)) ||
> +                (float64_is_zero(af) && float64_is_infinity(cf))) {
> +                r->u32[i] = 0x7fc00000;
> +            } else {
> +                float64 t = float64_mul(af, cf, &env->vec_status);
> +                float64 bf = float32_to_float64(b->f[i], &env->vec_status);
> +                if (unlikely(float64_is_infinity(t) &&
> +                             float64_is_infinity(bf) &&
> +                             float64_is_neg(t) == float64_is_neg(bf))) {
> +                    /* Magnitude subtraction of infinities */
> +                    r->u32[i] = 0x7fc00000;
> +                } else {
> +                    t = float64_sub(t, bf, &env->vec_status);
> +                    t = float64_chs(t);
> +                    r->f[i] = float64_to_float32(t, &env->vec_status);
> +                }
> +            }
> +        }
> +    }
> +}
> +

Same here.

>  void helper_vperm (ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b, ppc_avr_t *c)
>  {
>      ppc_avr_t result;
> diff --git a/target-ppc/translate.c b/target-ppc/translate.c
> index 6ff46e0..8b67333 100644
> --- a/target-ppc/translate.c
> +++ b/target-ppc/translate.c
> @@ -6577,6 +6577,7 @@ GEN_VAFORM_PAIRED(vmsumubm, vmsummbm, 18)
>  GEN_VAFORM_PAIRED(vmsumuhm, vmsumuhs, 19)
>  GEN_VAFORM_PAIRED(vmsumshm, vmsumshs, 20)
>  GEN_VAFORM_PAIRED(vsel, vperm, 21)
> +GEN_VAFORM_PAIRED(vmaddfp, vnmsubfp, 23)
>  
>  /***                           SPE extension                               
> ***/
>  /* Register moves */
> -- 
> 1.6.0.5
> 
> 
> 
> 

-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
address@hidden                 http://www.aurel32.net