diff options
Diffstat (limited to 'sysdeps/aarch64/fpu/sin_sve.c')
| -rw-r--r-- | sysdeps/aarch64/fpu/sin_sve.c | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/sysdeps/aarch64/fpu/sin_sve.c b/sysdeps/aarch64/fpu/sin_sve.c new file mode 100644 index 0000000000..c3f450d0ea --- /dev/null +++ b/sysdeps/aarch64/fpu/sin_sve.c @@ -0,0 +1,97 @@ +/* Double-precision vector (SVE) sin function. + + Copyright (C) 2023 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#include "sv_math.h" + +static const struct data +{ + double inv_pi, half_pi, inv_pi_over_2, pi_over_2_1, pi_over_2_2, pi_over_2_3, + shift; +} data = { + /* Polynomial coefficients are hard-wired in the FTMAD instruction. */ + .inv_pi = 0x1.45f306dc9c883p-2, + .half_pi = 0x1.921fb54442d18p+0, + .inv_pi_over_2 = 0x1.45f306dc9c882p-1, + .pi_over_2_1 = 0x1.921fb50000000p+0, + .pi_over_2_2 = 0x1.110b460000000p-26, + .pi_over_2_3 = 0x1.1a62633145c07p-54, + .shift = 0x1.8p52 +}; + +#define RangeVal 0x4160000000000000 /* asuint64 (0x1p23). */ + +static svfloat64_t NOINLINE +special_case (svfloat64_t x, svfloat64_t y, svbool_t cmp) +{ + return sv_call_f64 (sin, x, y, cmp); +} + +/* A fast SVE implementation of sin based on trigonometric + instructions (FTMAD, FTSSEL, FTSMUL). + Maximum observed error in 2.52 ULP: + SV_NAME_D1 (sin)(0x1.2d2b00df69661p+19) got 0x1.10ace8f3e786bp-40 + want 0x1.10ace8f3e7868p-40. */ +svfloat64_t SV_NAME_D1 (sin) (svfloat64_t x, const svbool_t pg) +{ + const struct data *d = ptr_barrier (&data); + + svfloat64_t r = svabs_f64_x (pg, x); + svuint64_t sign + = sveor_u64_x (pg, svreinterpret_u64_f64 (x), svreinterpret_u64_f64 (r)); + svbool_t cmp = svcmpge_n_u64 (pg, svreinterpret_u64_f64 (r), RangeVal); + + /* Load first two pio2-related constants to one vector. */ + svfloat64_t invpio2_and_pio2_1 + = svld1rq_f64 (svptrue_b64 (), &d->inv_pi_over_2); + + /* n = rint(|x|/(pi/2)). */ + svfloat64_t q = svmla_lane_f64 (sv_f64 (d->shift), r, invpio2_and_pio2_1, 0); + svfloat64_t n = svsub_n_f64_x (pg, q, d->shift); + + /* r = |x| - n*(pi/2) (range reduction into -pi/4 .. pi/4). */ + r = svmls_lane_f64 (r, n, invpio2_and_pio2_1, 1); + r = svmls_n_f64_x (pg, r, n, d->pi_over_2_2); + r = svmls_n_f64_x (pg, r, n, d->pi_over_2_3); + + /* Final multiplicative factor: 1.0 or x depending on bit #0 of q. */ + svfloat64_t f = svtssel_f64 (r, svreinterpret_u64_f64 (q)); + + /* sin(r) poly approx. */ + svfloat64_t r2 = svtsmul_f64 (r, svreinterpret_u64_f64 (q)); + svfloat64_t y = sv_f64 (0.0); + y = svtmad_f64 (y, r2, 7); + y = svtmad_f64 (y, r2, 6); + y = svtmad_f64 (y, r2, 5); + y = svtmad_f64 (y, r2, 4); + y = svtmad_f64 (y, r2, 3); + y = svtmad_f64 (y, r2, 2); + y = svtmad_f64 (y, r2, 1); + y = svtmad_f64 (y, r2, 0); + + /* Apply factor. */ + y = svmul_f64_x (pg, f, y); + + /* sign = y^sign. */ + y = svreinterpret_f64_u64 ( + sveor_u64_x (pg, svreinterpret_u64_f64 (y), sign)); + + if (__glibc_unlikely (svptest_any (pg, cmp))) + return special_case (x, y, cmp); + return y; +} |