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Subject: Re: [Qemu-devel] [PATCH 12/14] VSX Stage 4: Add Scalar SP Fused
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To: Tom Musta <tommusta@gmail.com>, qemu-devel@nongnu.org
Cc: qemu-ppc@nongnu.org

On 11/07/2013 06:31 AM, Tom Musta wrote:
>          }                                                                     \
> +                                                                              \
> +        if (r2sp) {                                                           \
> +            float32 tmp32 = float64_to_float32(xt_out.fld[i],                 \
> +                                               &env->fp_status);              \
> +            xt_out.fld[i] = float32_to_float64(tmp32, &env->fp_status);       \
> +        }                                                                     \
> +                                                                              \

You can't get correct results for a single-precision fma from a
double-precision fma and merely rounding the results.

See e.g. glibc's sysdeps/ieee754/dbl-64/s_fmaf.c.


r~