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/* Single-precision vector (Advanced SIMD) asinh 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_log1pf_inline.h"
#define SignMask v_u32 (0x80000000)
const static struct data
{
struct v_log1pf_data log1pf_consts;
uint32x4_t big_bound;
#if WANT_SIMD_EXCEPT
uint32x4_t tiny_bound;
#endif
} data = {
.log1pf_consts = V_LOG1PF_CONSTANTS_TABLE,
.big_bound = V4 (0x5f800000), /* asuint(0x1p64). */
#if WANT_SIMD_EXCEPT
.tiny_bound = V4 (0x30800000) /* asuint(0x1p-30). */
#endif
};
static float32x4_t NOINLINE VPCS_ATTR
special_case (float32x4_t x, float32x4_t y, uint32x4_t special)
{
return v_call_f32 (asinhf, x, y, special);
}
/* Single-precision implementation of vector asinh(x), using vector log1p.
Worst-case error is 2.66 ULP, at roughly +/-0.25:
__v_asinhf(0x1.01b04p-2) got 0x1.fe163ep-3 want 0x1.fe1638p-3. */
VPCS_ATTR float32x4_t NOINLINE V_NAME_F1 (asinh) (float32x4_t x)
{
const struct data *dat = ptr_barrier (&data);
uint32x4_t iax = vbicq_u32 (vreinterpretq_u32_f32 (x), SignMask);
float32x4_t ax = vreinterpretq_f32_u32 (iax);
uint32x4_t special = vcgeq_u32 (iax, dat->big_bound);
float32x4_t special_arg = x;
#if WANT_SIMD_EXCEPT
/* Sidestep tiny and large values to avoid inadvertently triggering
under/overflow. */
special = vorrq_u32 (special, vcltq_u32 (iax, dat->tiny_bound));
if (__glibc_unlikely (v_any_u32 (special)))
{
ax = v_zerofy_f32 (ax, special);
x = v_zerofy_f32 (x, special);
}
#endif
/* asinh(x) = log(x + sqrt(x * x + 1)).
For positive x, asinh(x) = log1p(x + x * x / (1 + sqrt(x * x + 1))). */
float32x4_t d
= vaddq_f32 (v_f32 (1), vsqrtq_f32 (vfmaq_f32 (v_f32 (1), x, x)));
float32x4_t y = log1pf_inline (
vaddq_f32 (ax, vdivq_f32 (vmulq_f32 (ax, ax), d)), dat->log1pf_consts);
if (__glibc_unlikely (v_any_u32 (special)))
return special_case (special_arg, vbslq_f32 (SignMask, x, y), special);
return vbslq_f32 (SignMask, x, y);
}
libmvec_hidden_def (V_NAME_F1 (asinh))
HALF_WIDTH_ALIAS_F1 (asinh)
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