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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>
This commit is contained in:
Emilio G. Cota 2018-03-17 00:30:40 -04:00 committed by Alex Bennée
parent ccf770ba73
commit f131bae8a7
1 changed files with 58 additions and 2 deletions
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60
fpu/softfloat.c
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@ -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.
*----------------------------------------------------------------------------*/