diff options
Diffstat (limited to 'math/aarch64/advsimd/v_sincospi_common.h')
-rw-r--r-- | math/aarch64/advsimd/v_sincospi_common.h | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/math/aarch64/advsimd/v_sincospi_common.h b/math/aarch64/advsimd/v_sincospi_common.h new file mode 100644 index 000000000000..438b141b9174 --- /dev/null +++ b/math/aarch64/advsimd/v_sincospi_common.h @@ -0,0 +1,64 @@ +/* + * Helper for Double-precision vector sincospi function. + * + * Copyright (c) 2024, Arm Limited. + * SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception + */ +#include "v_math.h" +#include "v_poly_f64.h" + +static const struct v_sincospi_data +{ + float64x2_t poly[10], range_val; +} v_sincospi_data = { + /* Polynomial coefficients generated using Remez algorithm, + see sinpi.sollya for details. */ + .poly = { V2 (0x1.921fb54442d184p1), V2 (-0x1.4abbce625be53p2), + V2 (0x1.466bc6775ab16p1), V2 (-0x1.32d2cce62dc33p-1), + V2 (0x1.507834891188ep-4), V2 (-0x1.e30750a28c88ep-8), + V2 (0x1.e8f48308acda4p-12), V2 (-0x1.6fc0032b3c29fp-16), + V2 (0x1.af86ae521260bp-21), V2 (-0x1.012a9870eeb7dp-25) }, + .range_val = V2 (0x1p63), +}; + +/* Double-precision vector function allowing calculation of both sin and cos in + one function call, using separate argument reduction and shared low-order + polynomials. + Approximation for vector double-precision sincospi(x). + Maximum Error 3.09 ULP: + _ZGVnN2v_sincospi_sin(0x1.7a41deb4b21e1p+14) got 0x1.fd54d0b327cf1p-1 + want 0x1.fd54d0b327cf4p-1 + Maximum Error 3.16 ULP: + _ZGVnN2v_sincospi_cos(-0x1.11e3c7e284adep-5) got 0x1.fd2da484ff3ffp-1 + want 0x1.fd2da484ff402p-1. */ +static inline float64x2x2_t +v_sincospi_inline (float64x2_t x, const struct v_sincospi_data *d) +{ + /* If r is odd, the sign of the result should be inverted for sinpi + and reintroduced for cospi. */ + uint64x2_t cmp = vcgeq_f64 (x, d->range_val); + uint64x2_t odd = vshlq_n_u64 ( + vbicq_u64 (vreinterpretq_u64_s64 (vcvtaq_s64_f64 (x)), cmp), 63); + + /* r = x - rint(x). */ + float64x2_t sr = vsubq_f64 (x, vrndaq_f64 (x)); + /* cospi(x) = sinpi(0.5 - abs(x)) for values -1/2 .. 1/2. */ + float64x2_t cr = vsubq_f64 (v_f64 (0.5), vabsq_f64 (sr)); + + /* Pairwise Horner approximation for y = sin(r * pi). */ + float64x2_t sr2 = vmulq_f64 (sr, sr); + float64x2_t sr4 = vmulq_f64 (sr2, sr2); + float64x2_t cr2 = vmulq_f64 (cr, cr); + float64x2_t cr4 = vmulq_f64 (cr2, cr2); + + float64x2_t ss = vmulq_f64 (v_pw_horner_9_f64 (sr2, sr4, d->poly), sr); + float64x2_t cc = vmulq_f64 (v_pw_horner_9_f64 (cr2, cr4, d->poly), cr); + + float64x2_t sinpix + = vreinterpretq_f64_u64 (veorq_u64 (vreinterpretq_u64_f64 (ss), odd)); + + float64x2_t cospix + = vreinterpretq_f64_u64 (veorq_u64 (vreinterpretq_u64_f64 (cc), odd)); + + return (float64x2x2_t){ sinpix, cospix }; +} |