Emilio G. Cota writes:
> Performance results for fp-bench:
>
> Host: Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz
> - before:
> sqrt-single: 42.30 MFlops
> sqrt-double: 22.97 MFlops
> - after:
> sqrt-single: 311.42 MFlops
> sqrt-double: 311.08 MFlops
>
> Here USE_FP makes a huge difference for f64's, with throughput
> going from ~200 MFlops to ~300 MFlops.
>
> Signed-off-by: Emilio G. Cota
Reviewed-by: Alex Bennée
> ---
> fpu/softfloat.c | 60 +++--
> 1 file changed, 58 insertions(+), 2 deletions(-)
>
> diff --git a/fpu/softfloat.c b/fpu/softfloat.c
> index e03feafb6f..4c6ecd1883 100644
> --- a/fpu/softfloat.c
> +++ b/fpu/softfloat.c
> @@ -3040,20 +3040,76 @@ float16 QEMU_FLATTEN float16_sqrt(float16 a,
> float_status *status)
> return float16_round_pack_canonical(pr, status);
> }
>
> -float32 QEMU_FLATTEN float32_sqrt(float32 a, float_status *status)
> +static float32 QEMU_SOFTFLOAT_ATTR
> +soft_f32_sqrt(float32 a, float_status *status)
> {
> FloatParts pa = float32_unpack_canonical(a, status);
> FloatParts pr = sqrt_float(pa, status, _params);
> return float32_round_pack_canonical(pr, status);
> }
>
> -float64 QEMU_FLATTEN float64_sqrt(float64 a, float_status *status)
> +static float64 QEMU_SOFTFLOAT_ATTR
> +soft_f64_sqrt(float64 a, float_status *status)
> {
> FloatParts pa = float64_unpack_canonical(a, status);
> FloatParts pr = sqrt_float(pa, status, _params);
> return float64_round_pack_canonical(pr, status);
> }
>
> +float32 QEMU_FLATTEN float32_sqrt(float32 xa, float_status *s)
> +{
> +union_float32 ua, ur;
> +
> +ua.s = xa;
> +if (unlikely(!can_use_fpu(s))) {
> +goto soft;
> +}
> +
> +float32_input_flush1(, s);
> +if (QEMU_HARDFLOAT_1F32_USE_FP) {
> +if (unlikely(!(fpclassify(ua.h) == FP_NORMAL ||
> + fpclassify(ua.h) == FP_ZERO) ||
> + signbit(ua.h))) {
> +goto soft;
> +}
> +} else if (unlikely(!float32_is_zero_or_normal(ua.s) ||
> +float32_is_neg(ua.s))) {
> +goto soft;
> +}
> +ur.h = sqrtf(ua.h);
> +return ur.s;
> +
> + soft:
> +return soft_f32_sqrt(ua.s, s);
> +}
> +
> +float64 QEMU_FLATTEN float64_sqrt(float64 xa, float_status *s)
> +{
> +union_float64 ua, ur;
> +
> +ua.s = xa;
> +if (unlikely(!can_use_fpu(s))) {
> +goto soft;
> +}
> +
> +float64_input_flush1(, s);
> +if (QEMU_HARDFLOAT_1F64_USE_FP) {
> +if (unlikely(!(fpclassify(ua.h) == FP_NORMAL ||
> + fpclassify(ua.h) == FP_ZERO) ||
> + signbit(ua.h))) {
> +goto soft;
> +}
> +} else if (unlikely(!float64_is_zero_or_normal(ua.s) ||
> +float64_is_neg(ua.s))) {
> +goto soft;
> +}
> +ur.h = sqrt(ua.h);
> +return ur.s;
> +
> + soft:
> +return soft_f64_sqrt(ua.s, s);
> +}
> +
>
> /*
> | The pattern for a default generated NaN.
>
> **/
--
Alex Bennée
