Performance results for fp-bench:
1. Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz
- before:
sqrt-single: 43.27 MFlops
sqrt-double: 24.81 MFlops
- after:
sqrt-single: 297.94 MFlops
sqrt-double: 210.46 MFlops
2. ARM Aarch64 A57 @ 2.4GHz
- before:
sqrt-single: 12.41 MFlops
sqrt-double: 6.22 MFlops
- after:
sqrt-single: 55.58 MFlops
sqrt-double: 40.63 MFlops
3. IBM POWER8E @ 2.1 GHz
- before:
sqrt-single: 17.01 MFlops
sqrt-double: 9.61 MFlops
- after:
sqrt-single: 104.17 MFlops
sqrt-double: 133.32 MFlops
Here none of the machines got faster from enabling USE_FP. For
instance, on x86_64 sqrt is 23% slower for single precision,
with it enabled, and 17% slower for double precision.
Signed-off-by: Emilio G. Cota <c...@braap.org>
---
fpu/softfloat.c | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 71 insertions(+), 2 deletions(-)
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index ce14c87..5434d29 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -2717,20 +2717,89 @@ float16 __attribute__((flatten)) float16_sqrt(float16
a, float_status *status)
return float16_round_pack_canonical(pr, status);
}
-float32 __attribute__((flatten)) float32_sqrt(float32 a, float_status *status)
+static float32 QEMU_SOFTFLOAT_ATTR
+soft_float32_sqrt(float32 a, float_status *status)
{
FloatParts pa = float32_unpack_canonical(a, status);
FloatParts pr = sqrt_float(pa, status, &float32_params);
return float32_round_pack_canonical(pr, status);
}
-float64 __attribute__((flatten)) float64_sqrt(float64 a, float_status *status)
+static float64 QEMU_SOFTFLOAT_ATTR
+soft_float64_sqrt(float64 a, float_status *status)
{
FloatParts pa = float64_unpack_canonical(a, status);
FloatParts pr = sqrt_float(pa, status, &float64_params);
return float64_round_pack_canonical(pr, status);
}
+#define GEN_SQRT_SF(name, soft_t, host_t, host_sqrt_func) \
+ static soft_t name(soft_t a, float_status *s) \
+ { \
+ if (QEMU_NO_HARDFLOAT) { \
+ goto soft; \
+ } \
+ soft_t ## _input_flush1(&a, s); \
+ if (likely((soft_t ## _is_normal(a) || soft_t ## _is_zero(a)) && \
+ !soft_t ## _is_neg(a) && \
+ can_use_fpu(s))) { \
+ host_t ha = soft_t ## _to_ ## host_t(a); \
+ host_t hr = host_sqrt_func(ha); \
+ \
+ return host_t ## _to_ ## soft_t(hr); \
+ } \
+ soft: \
+ return soft_ ## soft_t ## _sqrt(a, s); \
+ }
+
+#define GEN_SQRT_FP(name, soft_t, host_t, host_sqrt_func) \
+ static soft_t name(soft_t a, float_status *s) \
+ { \
+ host_t ha; \
+ \
+ if (QEMU_NO_HARDFLOAT) { \
+ goto soft; \
+ } \
+ soft_t ## _input_flush1(&a, s); \
+ ha = soft_t ## _to_ ## host_t(a); \
+ if (likely((fpclassify(ha) == FP_NORMAL || \
+ fpclassify(ha) == FP_ZERO) && \
+ !signbit(ha) && \
+ can_use_fpu(s))) { \
+ host_t hr = host_sqrt_func(ha); \
+ \
+ return host_t ## _to_ ## soft_t(hr); \
+ } \
+ soft: \
+ return soft_ ## soft_t ## _sqrt(a, s); \
+ }
+
+GEN_SQRT_SF(f32_sqrt, float32, float, sqrtf)
+GEN_SQRT_SF(f64_sqrt, float64, double, sqrt)
+#undef GEN_SQRT_SF
+
+GEN_SQRT_FP(float_sqrt, float32, float, sqrtf)
+GEN_SQRT_FP(double_sqrt, float64, double, sqrt)
+#undef GEN_SQRT_FP
+
+float32 __attribute__((flatten)) float32_sqrt(float32 a, float_status *s)
+{
+ if (QEMU_HARDFLOAT_1F32_USE_FP) {
+ return float_sqrt(a, s);
+ } else {
+ return f32_sqrt(a, s);
+ }
+}
+
+float64 __attribute__((flatten)) float64_sqrt(float64 a, float_status *s)
+{
+ if (QEMU_HARDFLOAT_1F64_USE_FP) {
+ return double_sqrt(a, s);
+ } else {
+ return f64_sqrt(a, s);
+ }
+}
+
/*----------------------------------------------------------------------------
| Takes a 64-bit fixed-point value `absZ' with binary point between bits 6
--
2.7.4
