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hardfloat: implement float32/64 division 

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

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 00:45:01 -04:00 committed by Alex Bennée
parent 2dfabc86e6
commit 4a6295613f
1 changed files with 62 additions and 2 deletions
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64
fpu/softfloat.c
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@ -1628,7 +1628,8 @@ 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);
@ -1637,7 +1638,8 @@ 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);
@ -1646,6 +1648,64 @@ 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
*