Re: [Qemu-devel] [PATCH 07/14] Add v{add,sub}fp instructions

[Aurelien Jarno]

On Thu, Jan 22, 2009 at 12:44:07PM -0800, Nathan Froyd wrote:
> Split up vaddfp and vsubfp so that we can properly handle magnitude
> subtraction of infinities.
> 
> Signed-off-by: Nathan Froyd <address@hidden>
> ---
>  target-ppc/helper.h    |    2 ++
>  target-ppc/op_helper.c |   27 +++++++++++++++++++++++++++
>  target-ppc/translate.c |    2 ++
>  3 files changed, 31 insertions(+), 0 deletions(-)
> 
> diff --git a/target-ppc/helper.h b/target-ppc/helper.h
> index ebdeabe..a5d1972 100644
> --- a/target-ppc/helper.h
> +++ b/target-ppc/helper.h
> @@ -232,6 +232,8 @@ DEF_HELPER_3(vsum2sws, void, avr, avr, avr)
>  DEF_HELPER_3(vsum4sbs, void, avr, avr, avr)
>  DEF_HELPER_3(vsum4shs, void, avr, avr, avr)
>  DEF_HELPER_3(vsum4ubs, void, avr, avr, avr)
> +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)
>  
> diff --git a/target-ppc/op_helper.c b/target-ppc/op_helper.c
> index 717bbd4..d952113 100644
> --- a/target-ppc/op_helper.c
> +++ b/target-ppc/op_helper.c
> @@ -2102,6 +2102,33 @@ VARITH(uwm, u32)
>  #undef VARITH_DO
>  #undef VARITH
>  
> +void helper_vaddfp (ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b)
> +{
> +    int i;
> +    for (i = 0; i < ARRAY_SIZE(r->f); i++) {
> +        HANDLE_NAN2(r->f[i], a->f[i], b->f[i]) {
> +            r->f[i] = float32_add(a->f[i], b->f[i], &env->vec_status);
> +        }
> +    }
> +}
> +
> +void helper_vsubfp (ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b)
> +{
> +    int i;
> +    for (i = 0; i < ARRAY_SIZE(r->f); i++) {
> +        HANDLE_NAN2(r->f[i], a->f[i], b->f[i]) {
> +            if (unlikely(float32_is_infinity(a->f[i]) &&
> +                         float32_is_infinity(b->f[i]) &&
> +                         float32_is_neg(a->f[i]) == 
> float32_is_neg(b->f[i]))) {
> +                /* Magnitude subtraction of infinities */
> +                r->u32[i] = 0x7fc00000;

I think this case is already handled by the softfloat code.

> +            } else {
> +                r->f[i] = float32_sub(a->f[i], b->f[i], &env->vec_status);
> +            }
> +        }
> +    }
> +}
> +
>  #define VARITHSAT_CASE(type, op, cvt, element)                          \
>      {                                                                   \
>          type result = (type)a->element[i] op (type)b->element[i];       \
> diff --git a/target-ppc/translate.c b/target-ppc/translate.c
> index 35693e0..6ff46e0 100644
> --- a/target-ppc/translate.c
> +++ b/target-ppc/translate.c
> @@ -6395,6 +6395,8 @@ GEN_VXFORM(vsum4sbs, 4, 28);
>  GEN_VXFORM(vsum4shs, 4, 25);
>  GEN_VXFORM(vsum2sws, 4, 26);
>  GEN_VXFORM(vsumsws, 4, 30);
> +GEN_VXFORM(vaddfp, 5, 0);
> +GEN_VXFORM(vsubfp, 5, 1);
>  GEN_VXFORM(vmaxfp, 5, 10);
>  GEN_VXFORM(vminfp, 5, 11);
>  
> -- 
> 1.6.0.5
> 
> 
> 
> 

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