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authorEmilio G. Cota <cota@braap.org>2018-03-17 00:30:40 -0400
committerAlex Bennée <alex.bennee@linaro.org>2018-12-17 08:25:25 +0000
commitf131bae8a7b7ed1928cc94c69df291db609c316a (patch)
tree10c20d7f1abec552934fd03c05450f62dc9232da /fpu
parentccf770ba7396c240ca8a1564740083742dd04c08 (diff)
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hardfloat: implement float32/64 square root
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. Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Diffstat (limited to 'fpu')
-rw-r--r--fpu/softfloat.c60
1 files changed, 58 insertions, 2 deletions
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 7554d63..fbd66fd 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -3044,20 +3044,76 @@ 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, &float32_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, &float64_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(&ua.s, 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(&ua.s, 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.
*----------------------------------------------------------------------------*/