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[Qemu-devel] [PATCH v6 10/13] hardfloat: implement float32/64 division

Emilio G. Cota posted 13 patches 7 years, 2 months ago
[Qemu-devel] [PATCH v6 10/13] hardfloat: implement float32/64 division
Posted by Emilio G. Cota 7 years, 2 months ago 
Performance results for fp-bench:

1. Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz
- before:
div-single: 34.84 MFlops
div-double: 34.04 MFlops
- after:
div-single: 275.23 MFlops
div-double: 216.38 MFlops

2. ARM Aarch64 A57 @ 2.4GHz
- before:
div-single: 9.33 MFlops
div-double: 9.30 MFlops
- after:
div-single: 51.55 MFlops
div-double: 15.09 MFlops

3. IBM POWER8E @ 2.1 GHz
- before:
div-single: 25.65 MFlops
div-double: 24.91 MFlops
- after:
div-single: 96.83 MFlops
div-double: 31.01 MFlops

Here setting 2FP64_USE_FP to 1 pays off for x86_64:
[1] 215.97 vs [0] 62.15 MFlops

Signed-off-by: Emilio G. Cota <cota@braap.org>
---
 fpu/softfloat.c | 64 +++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 62 insertions(+), 2 deletions(-)

diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 58e67d9b80..e35ebfaae7 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -1624,7 +1624,8 @@ float16 float16_div(float16 a, float16 b, float_status *status)
     return float16_round_pack_canonical(pr, status);
 }
 
-float32 float32_div(float32 a, float32 b, float_status *status)
+static float32 QEMU_SOFTFLOAT_ATTR
+soft_f32_div(float32 a, float32 b, float_status *status)
 {
     FloatParts pa = float32_unpack_canonical(a, status);
     FloatParts pb = float32_unpack_canonical(b, status);
@@ -1633,7 +1634,8 @@ float32 float32_div(float32 a, float32 b, float_status *status)
     return float32_round_pack_canonical(pr, status);
 }
 
-float64 float64_div(float64 a, float64 b, float_status *status)
+static float64 QEMU_SOFTFLOAT_ATTR
+soft_f64_div(float64 a, float64 b, float_status *status)
 {
     FloatParts pa = float64_unpack_canonical(a, status);
     FloatParts pb = float64_unpack_canonical(b, status);
@@ -1642,6 +1644,64 @@ float64 float64_div(float64 a, float64 b, float_status *status)
     return float64_round_pack_canonical(pr, status);
 }
 
+static float hard_f32_div(float a, float b)
+{
+    return a / b;
+}
+
+static double hard_f64_div(double a, double b)
+{
+    return a / b;
+}
+
+static bool f32_div_pre(union_float32 a, union_float32 b)
+{
+    if (QEMU_HARDFLOAT_2F32_USE_FP) {
+        return (fpclassify(a.h) == FP_NORMAL || fpclassify(a.h) == FP_ZERO) &&
+               fpclassify(b.h) == FP_NORMAL;
+    }
+    return float32_is_zero_or_normal(a.s) && float32_is_normal(b.s);
+}
+
+static bool f64_div_pre(union_float64 a, union_float64 b)
+{
+    if (QEMU_HARDFLOAT_2F64_USE_FP) {
+        return (fpclassify(a.h) == FP_NORMAL || fpclassify(a.h) == FP_ZERO) &&
+               fpclassify(b.h) == FP_NORMAL;
+    }
+    return float64_is_zero_or_normal(a.s) && float64_is_normal(b.s);
+}
+
+static bool f32_div_post(union_float32 a, union_float32 b)
+{
+    if (QEMU_HARDFLOAT_2F32_USE_FP) {
+        return fpclassify(a.h) != FP_ZERO;
+    }
+    return !float32_is_zero(a.s);
+}
+
+static bool f64_div_post(union_float64 a, union_float64 b)
+{
+    if (QEMU_HARDFLOAT_2F64_USE_FP) {
+        return fpclassify(a.h) != FP_ZERO;
+    }
+    return !float64_is_zero(a.s);
+}
+
+float32 QEMU_FLATTEN
+float32_div(float32 a, float32 b, float_status *s)
+{
+    return float32_gen2(a, b, s, hard_f32_div, soft_f32_div,
+                        f32_div_pre, f32_div_post, NULL, NULL);
+}
+
+float64 QEMU_FLATTEN
+float64_div(float64 a, float64 b, float_status *s)
+{
+    return float64_gen2(a, b, s, hard_f64_div, soft_f64_div,
+                        f64_div_pre, f64_div_post, NULL, NULL);
+}
+
 /*
  * Float to Float conversions
  *
-- 
2.17.1
Re: [Qemu-devel] [PATCH v6 10/13] hardfloat: implement float32/64 division
Posted by Alex Bennée 7 years, 2 months ago 
Emilio G. Cota <cota@braap.org> writes:

> Performance results for fp-bench:
>
> 1. Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz
> - before:
> div-single: 34.84 MFlops
> div-double: 34.04 MFlops
> - after:
> div-single: 275.23 MFlops
> div-double: 216.38 MFlops
>
> 2. ARM Aarch64 A57 @ 2.4GHz
> - before:
> div-single: 9.33 MFlops
> div-double: 9.30 MFlops
> - after:
> div-single: 51.55 MFlops
> div-double: 15.09 MFlops
>
> 3. IBM POWER8E @ 2.1 GHz
> - before:
> div-single: 25.65 MFlops
> div-double: 24.91 MFlops
> - after:
> div-single: 96.83 MFlops
> div-double: 31.01 MFlops
>
> Here setting 2FP64_USE_FP to 1 pays off for x86_64:
> [1] 215.97 vs [0] 62.15 MFlops
>
> Signed-off-by: Emilio G. Cota <cota@braap.org>

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

> ---
>  fpu/softfloat.c | 64 +++++++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 62 insertions(+), 2 deletions(-)
>
> diff --git a/fpu/softfloat.c b/fpu/softfloat.c
> index 58e67d9b80..e35ebfaae7 100644
> --- a/fpu/softfloat.c
> +++ b/fpu/softfloat.c
> @@ -1624,7 +1624,8 @@ float16 float16_div(float16 a, float16 b, float_status *status)
>      return float16_round_pack_canonical(pr, status);
>  }
>
> -float32 float32_div(float32 a, float32 b, float_status *status)
> +static float32 QEMU_SOFTFLOAT_ATTR
> +soft_f32_div(float32 a, float32 b, float_status *status)
>  {
>      FloatParts pa = float32_unpack_canonical(a, status);
>      FloatParts pb = float32_unpack_canonical(b, status);
> @@ -1633,7 +1634,8 @@ float32 float32_div(float32 a, float32 b, float_status *status)
>      return float32_round_pack_canonical(pr, status);
>  }
>
> -float64 float64_div(float64 a, float64 b, float_status *status)
> +static float64 QEMU_SOFTFLOAT_ATTR
> +soft_f64_div(float64 a, float64 b, float_status *status)
>  {
>      FloatParts pa = float64_unpack_canonical(a, status);
>      FloatParts pb = float64_unpack_canonical(b, status);
> @@ -1642,6 +1644,64 @@ float64 float64_div(float64 a, float64 b, float_status *status)
>      return float64_round_pack_canonical(pr, status);
>  }
>
> +static float hard_f32_div(float a, float b)
> +{
> +    return a / b;
> +}
> +
> +static double hard_f64_div(double a, double b)
> +{
> +    return a / b;
> +}
> +
> +static bool f32_div_pre(union_float32 a, union_float32 b)
> +{
> +    if (QEMU_HARDFLOAT_2F32_USE_FP) {
> +        return (fpclassify(a.h) == FP_NORMAL || fpclassify(a.h) == FP_ZERO) &&
> +               fpclassify(b.h) == FP_NORMAL;
> +    }
> +    return float32_is_zero_or_normal(a.s) && float32_is_normal(b.s);
> +}
> +
> +static bool f64_div_pre(union_float64 a, union_float64 b)
> +{
> +    if (QEMU_HARDFLOAT_2F64_USE_FP) {
> +        return (fpclassify(a.h) == FP_NORMAL || fpclassify(a.h) == FP_ZERO) &&
> +               fpclassify(b.h) == FP_NORMAL;
> +    }
> +    return float64_is_zero_or_normal(a.s) && float64_is_normal(b.s);
> +}
> +
> +static bool f32_div_post(union_float32 a, union_float32 b)
> +{
> +    if (QEMU_HARDFLOAT_2F32_USE_FP) {
> +        return fpclassify(a.h) != FP_ZERO;
> +    }
> +    return !float32_is_zero(a.s);
> +}
> +
> +static bool f64_div_post(union_float64 a, union_float64 b)
> +{
> +    if (QEMU_HARDFLOAT_2F64_USE_FP) {
> +        return fpclassify(a.h) != FP_ZERO;
> +    }
> +    return !float64_is_zero(a.s);
> +}
> +
> +float32 QEMU_FLATTEN
> +float32_div(float32 a, float32 b, float_status *s)
> +{
> +    return float32_gen2(a, b, s, hard_f32_div, soft_f32_div,
> +                        f32_div_pre, f32_div_post, NULL, NULL);
> +}
> +
> +float64 QEMU_FLATTEN
> +float64_div(float64 a, float64 b, float_status *s)
> +{
> +    return float64_gen2(a, b, s, hard_f64_div, soft_f64_div,
> +                        f64_div_pre, f64_div_post, NULL, NULL);
> +}
> +
>  /*
>   * Float to Float conversions
>   *


--
Alex Bennée

Patchew 2.1-devel-b67e4c2

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