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[PATCH 70/72] softfloat: Convert float32_exp2 to FloatParts
From: |
Richard Henderson |
Subject: |
[PATCH 70/72] softfloat: Convert float32_exp2 to FloatParts |
Date: |
Fri, 7 May 2021 18:48:00 -0700 |
Keep the intermediate results in FloatParts instead of
converting back and forth between float64. Use muladd
instead of separate mul+add.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
fpu/softfloat.c | 53 +++++++++++++++++++++----------------------------
1 file changed, 23 insertions(+), 30 deletions(-)
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index b89ec4b832..906bb427ae 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -5212,47 +5212,40 @@ static const float64 float32_exp2_coefficients[15] =
float32 float32_exp2(float32 a, float_status *status)
{
- bool aSign;
- int aExp;
- uint32_t aSig;
- float64 r, x, xn;
+ FloatParts64 xp, xnp, tp, rp;
int i;
- a = float32_squash_input_denormal(a, status);
- aSig = extractFloat32Frac( a );
- aExp = extractFloat32Exp( a );
- aSign = extractFloat32Sign( a );
-
- if ( aExp == 0xFF) {
- if (aSig) {
- return propagateFloat32NaN(a, float32_zero, status);
+ float32_unpack_canonical(&xp, a, status);
+ if (unlikely(xp.cls != float_class_normal)) {
+ switch (xp.cls) {
+ case float_class_snan:
+ case float_class_qnan:
+ parts_return_nan(&xp, status);
+ return float32_round_pack_canonical(&xp, status);
+ case float_class_inf:
+ return xp.sign ? float32_zero : a;
+ case float_class_zero:
+ return float32_one;
+ default:
+ break;
}
- return (aSign) ? float32_zero : a;
- }
- if (aExp == 0) {
- if (aSig == 0) return float32_one;
+ g_assert_not_reached();
}
float_raise(float_flag_inexact, status);
- /* ******************************* */
- /* using float64 for approximation */
- /* ******************************* */
- x = float32_to_float64(a, status);
- x = float64_mul(x, float64_ln2, status);
+ float64_unpack_canonical(&xnp, float64_ln2, status);
+ xp = *parts_mul(&xp, &tp, status);
+ xnp = xp;
- xn = x;
- r = float64_one;
+ float64_unpack_canonical(&rp, float64_one, status);
for (i = 0 ; i < 15 ; i++) {
- float64 f;
-
- f = float64_mul(xn, float32_exp2_coefficients[i], status);
- r = float64_add(r, f, status);
-
- xn = float64_mul(xn, x, status);
+ float64_unpack_canonical(&tp, float32_exp2_coefficients[i], status);
+ rp = *parts_muladd(&tp, &xp, &rp, 0, status);
+ xnp = *parts_mul(&xnp, &xp, status);
}
- return float64_to_float32(r, status);
+ return float32_round_pack_canonical(&rp, status);
}
/*----------------------------------------------------------------------------
--
2.25.1
- Re: [PATCH 50/72] softfloat: Move minmax_flags to softfloat-parts.c.inc, (continued)
- [PATCH 51/72] softfloat: Move compare_floats to softfloat-parts.c.inc, Richard Henderson, 2021/05/07
- [PATCH 52/72] softfloat: Move scalbn_decomposed to softfloat-parts.c.inc, Richard Henderson, 2021/05/07
- [PATCH 53/72] softfloat: Move sqrt_float to softfloat-parts.c.inc, Richard Henderson, 2021/05/07
- [PATCH 60/72] softfloat: Convert floatx80_mul to FloatParts, Richard Henderson, 2021/05/07
- [PATCH 62/72] softfloat: Convert floatx80_sqrt to FloatParts, Richard Henderson, 2021/05/07
- [PATCH 57/72] softfloat: Adjust parts_uncanon_normal for floatx80, Richard Henderson, 2021/05/07
- [PATCH 65/72] softfloat: Convert integer to floatx80 to FloatParts, Richard Henderson, 2021/05/07
- [PATCH 68/72] softfloat: Convert floatx80_scalbn to FloatParts, Richard Henderson, 2021/05/07
- [PATCH 66/72] softfloat: Convert floatx80 float conversions to FloatParts, Richard Henderson, 2021/05/07
- [PATCH 70/72] softfloat: Convert float32_exp2 to FloatParts,
Richard Henderson <=
- [PATCH 55/72] softfloat: Reduce FloatFmt, Richard Henderson, 2021/05/07
- [PATCH 58/72] tests/fp/fp-test: Reverse order of floatx80 precision tests, Richard Henderson, 2021/05/07
- [PATCH 61/72] softfloat: Convert floatx80_div to FloatParts, Richard Henderson, 2021/05/07
- [PATCH 59/72] softfloat: Convert floatx80_add/sub to FloatParts, Richard Henderson, 2021/05/07
- [PATCH 71/72] softfloat: Move floatN_log2 to softfloat-parts.c.inc, Richard Henderson, 2021/05/07
- [PATCH 56/72] softfloat: Introduce Floatx80RoundPrec, Richard Henderson, 2021/05/07
- [PATCH 63/72] softfloat: Convert floatx80_round to FloatParts, Richard Henderson, 2021/05/07
- [PATCH 64/72] softfloat: Convert floatx80_round_to_int to FloatParts, Richard Henderson, 2021/05/07
- [PATCH 69/72] softfloat: Convert floatx80 compare to FloatParts, Richard Henderson, 2021/05/07