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89 lines
3.0 KiB
C
89 lines
3.0 KiB
C
/* Single-precision vector (Advanced SIMD) sinh function
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Copyright (C) 2024 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include "v_math.h"
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#include "v_expm1f_inline.h"
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static const struct data
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{
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struct v_expm1f_data expm1f_consts;
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uint32x4_t halff;
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#if WANT_SIMD_EXCEPT
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uint32x4_t tiny_bound, thresh;
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#else
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uint32x4_t oflow_bound;
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#endif
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} data = {
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.expm1f_consts = V_EXPM1F_DATA,
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.halff = V4 (0x3f000000),
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#if WANT_SIMD_EXCEPT
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/* 0x1.6a09e8p-32, below which expm1f underflows. */
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.tiny_bound = V4 (0x2fb504f4),
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/* asuint(oflow_bound) - asuint(tiny_bound). */
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.thresh = V4 (0x12fbbbb3),
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#else
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/* 0x1.61814ep+6, above which expm1f helper overflows. */
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.oflow_bound = V4 (0x42b0c0a7),
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#endif
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};
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static float32x4_t NOINLINE VPCS_ATTR
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special_case (float32x4_t x, float32x4_t y, uint32x4_t special)
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{
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return v_call_f32 (sinhf, x, y, special);
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}
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/* Approximation for vector single-precision sinh(x) using expm1.
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sinh(x) = (exp(x) - exp(-x)) / 2.
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The maximum error is 2.26 ULP:
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_ZGVnN4v_sinhf (0x1.e34a9ep-4) got 0x1.e469ep-4
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want 0x1.e469e4p-4. */
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float32x4_t VPCS_ATTR NOINLINE V_NAME_F1 (sinh) (float32x4_t x)
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{
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const struct data *d = ptr_barrier (&data);
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uint32x4_t ix = vreinterpretq_u32_f32 (x);
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float32x4_t ax = vabsq_f32 (x);
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uint32x4_t iax = vreinterpretq_u32_f32 (ax);
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uint32x4_t sign = veorq_u32 (ix, iax);
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float32x4_t halfsign = vreinterpretq_f32_u32 (vorrq_u32 (sign, d->halff));
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#if WANT_SIMD_EXCEPT
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uint32x4_t special = vcgeq_u32 (vsubq_u32 (iax, d->tiny_bound), d->thresh);
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ax = v_zerofy_f32 (ax, special);
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#else
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uint32x4_t special = vcgeq_u32 (iax, d->oflow_bound);
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#endif
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/* Up to the point that expm1f overflows, we can use it to calculate sinhf
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using a slight rearrangement of the definition of asinh. This allows us
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to retain acceptable accuracy for very small inputs. */
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float32x4_t t = expm1f_inline (ax, &d->expm1f_consts);
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t = vaddq_f32 (t, vdivq_f32 (t, vaddq_f32 (t, v_f32 (1.0))));
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/* Fall back to the scalar variant for any lanes that should trigger an
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exception. */
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if (__glibc_unlikely (v_any_u32 (special)))
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return special_case (x, vmulq_f32 (t, halfsign), special);
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return vmulq_f32 (t, halfsign);
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}
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libmvec_hidden_def (V_NAME_F1 (sinh))
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HALF_WIDTH_ALIAS_F1 (sinh)
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