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| author | Joana Cruz <Joana.Cruz@arm.com> | 2024-01-17 16:55:54 +0000 |
|---|---|---|
| committer | Pierre Blanchard <pierre.blanchard@arm.com> | 2024-01-17 16:58:34 +0000 |
| commit | c0b94284f73b1fcab907b42ff183c7c598e2f645 (patch) | |
| tree | cf07b7958c81cf93fea16853fdd4f12d67a1d66d | |
| parent | f0e243c8def8f0c1ef08ef74d9498f3db139cfed (diff) | |
| download | arm-optimized-routines-c0b94284f73b1fcab907b42ff183c7c598e2f645.tar.gz | |
pl/math: Optimizing SVE atan2
* Implement return value trick;
* Use shift and logical operations to compute shift;
* Remove mask in sign computation;
No changes to ULP max error.
| -rw-r--r-- | pl/math/sv_atan2_2u5.c | 31 |
1 files changed, 15 insertions, 16 deletions
diff --git a/pl/math/sv_atan2_2u5.c b/pl/math/sv_atan2_2u5.c index 00530a3..1026424 100644 --- a/pl/math/sv_atan2_2u5.c +++ b/pl/math/sv_atan2_2u5.c @@ -1,7 +1,7 @@ /* * Double-precision vector atan2(x) function. * - * Copyright (c) 2021-2023, Arm Limited. + * Copyright (c) 2021-2024, Arm Limited. * SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception */ @@ -27,9 +27,6 @@ static const struct data .pi_over_2 = 0x1.921fb54442d18p+0, }; -/* Useful constants. */ -#define SignMask sv_u64 (0x8000000000000000) - /* Special cases i.e. 0, infinity, nan (fall back to scalar calls). */ static svfloat64_t NOINLINE special_case (svfloat64_t y, svfloat64_t x, svfloat64_t ret, @@ -62,14 +59,15 @@ svfloat64_t SV_NAME_D2 (atan2) (svfloat64_t y, svfloat64_t x, const svbool_t pg) svbool_t cmp_y = zeroinfnan (iy, pg); svbool_t cmp_xy = svorr_z (pg, cmp_x, cmp_y); - svuint64_t sign_x = svand_x (pg, ix, SignMask); - svuint64_t sign_y = svand_x (pg, iy, SignMask); - svuint64_t sign_xy = sveor_x (pg, sign_x, sign_y); - svfloat64_t ax = svabs_x (pg, x); svfloat64_t ay = svabs_x (pg, y); + svuint64_t iax = svreinterpret_u64 (ax); + svuint64_t iay = svreinterpret_u64 (ay); + + svuint64_t sign_x = sveor_x (pg, ix, iax); + svuint64_t sign_y = sveor_x (pg, iy, iay); + svuint64_t sign_xy = sveor_x (pg, sign_x, sign_y); - svbool_t pred_xlt0 = svcmplt (pg, x, 0.0); svbool_t pred_aygtax = svcmpgt (pg, ay, ax); /* Set up z for call to atan. */ @@ -78,8 +76,9 @@ svfloat64_t SV_NAME_D2 (atan2) (svfloat64_t y, svfloat64_t x, const svbool_t pg) svfloat64_t z = svdiv_x (pg, n, d); /* Work out the correct shift. */ - svfloat64_t shift = svsel (pred_xlt0, sv_f64 (-2.0), sv_f64 (0.0)); - shift = svsel (pred_aygtax, svadd_x (pg, shift, 1.0), shift); + svfloat64_t shift = svreinterpret_f64 (svlsr_x (pg, sign_x, 1)); + shift = svsel (pred_aygtax, sv_f64 (1.0), shift); + shift = svreinterpret_f64 (svorr_x (pg, sign_x, svreinterpret_u64 (shift))); shift = svmul_x (pg, shift, data_ptr->pi_over_2); /* Use split Estrin scheme for P(z^2) with deg(P)=19. */ @@ -99,12 +98,12 @@ svfloat64_t SV_NAME_D2 (atan2) (svfloat64_t y, svfloat64_t x, const svbool_t pg) ret = svadd_m (pg, ret, shift); /* Account for the sign of x and y. */ - ret = svreinterpret_f64 (sveor_x (pg, svreinterpret_u64 (ret), sign_xy)); - if (unlikely (svptest_any (pg, cmp_xy))) - return special_case (y, x, ret, cmp_xy); - - return ret; + return special_case ( + y, x, + svreinterpret_f64 (sveor_x (pg, svreinterpret_u64 (ret), sign_xy)), + cmp_xy); + return svreinterpret_f64 (sveor_x (pg, svreinterpret_u64 (ret), sign_xy)); } /* Arity of 2 means no mathbench entry emitted. See test/mathbench_funcs.h. */ |