/* Single-precision vector (Advanced SIMD) sinh function

   Copyright (C) 2024 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 "v_math.h"
#include "v_expm1f_inline.h"

static const struct data
{
  struct v_expm1f_data expm1f_consts;
  uint32x4_t halff;
#if WANT_SIMD_EXCEPT
  uint32x4_t tiny_bound, thresh;
#else
  uint32x4_t oflow_bound;
#endif
} data = {
  .expm1f_consts = V_EXPM1F_DATA,
  .halff = V4 (0x3f000000),
#if WANT_SIMD_EXCEPT
  /* 0x1.6a09e8p-32, below which expm1f underflows.  */
  .tiny_bound = V4 (0x2fb504f4),
  /* asuint(oflow_bound) - asuint(tiny_bound).  */
  .thresh = V4 (0x12fbbbb3),
#else
  /* 0x1.61814ep+6, above which expm1f helper overflows.  */
  .oflow_bound = V4 (0x42b0c0a7),
#endif
};

static float32x4_t NOINLINE VPCS_ATTR
special_case (float32x4_t x, float32x4_t y, uint32x4_t special)
{
  return v_call_f32 (sinhf, x, y, special);
}

/* Approximation for vector single-precision sinh(x) using expm1.
   sinh(x) = (exp(x) - exp(-x)) / 2.
   The maximum error is 2.26 ULP:
   _ZGVnN4v_sinhf (0x1.e34a9ep-4) got 0x1.e469ep-4
				 want 0x1.e469e4p-4.  */
float32x4_t VPCS_ATTR NOINLINE V_NAME_F1 (sinh) (float32x4_t x)
{
  const struct data *d = ptr_barrier (&data);

  uint32x4_t ix = vreinterpretq_u32_f32 (x);
  float32x4_t ax = vabsq_f32 (x);
  uint32x4_t iax = vreinterpretq_u32_f32 (ax);
  uint32x4_t sign = veorq_u32 (ix, iax);
  float32x4_t halfsign = vreinterpretq_f32_u32 (vorrq_u32 (sign, d->halff));

#if WANT_SIMD_EXCEPT
  uint32x4_t special = vcgeq_u32 (vsubq_u32 (iax, d->tiny_bound), d->thresh);
  ax = v_zerofy_f32 (ax, special);
#else
  uint32x4_t special = vcgeq_u32 (iax, d->oflow_bound);
#endif

  /* Up to the point that expm1f overflows, we can use it to calculate sinhf
       using a slight rearrangement of the definition of asinh. This allows us
     to retain acceptable accuracy for very small inputs.  */
  float32x4_t t = expm1f_inline (ax, &d->expm1f_consts);
  t = vaddq_f32 (t, vdivq_f32 (t, vaddq_f32 (t, v_f32 (1.0))));

  /* Fall back to the scalar variant for any lanes that should trigger an
     exception.  */
  if (__glibc_unlikely (v_any_u32 (special)))
    return special_case (x, vmulq_f32 (t, halfsign), special);

  return vmulq_f32 (t, halfsign);
}
libmvec_hidden_def (V_NAME_F1 (sinh))
HALF_WIDTH_ALIAS_F1 (sinh)