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/* Single-precision vector (Advanced SIMD) hypot 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"
#if WANT_SIMD_EXCEPT
static const struct data
{
uint32x4_t tiny_bound, thres;
} data = {
.tiny_bound = V4 (0x20000000), /* asuint (0x1p-63). */
.thres = V4 (0x3f000000), /* asuint (0x1p63) - tiny_bound. */
};
#else
static const struct data
{
uint32x4_t tiny_bound;
uint16x8_t thres;
} data = {
.tiny_bound = V4 (0x0C800000), /* asuint (0x1p-102). */
.thres = V8 (0x7300), /* asuint (inf) - tiny_bound. */
};
#endif
static float32x4_t VPCS_ATTR NOINLINE
special_case (float32x4_t x, float32x4_t y, float32x4_t sqsum,
uint16x4_t special)
{
return v_call2_f32 (hypotf, x, y, vsqrtq_f32 (sqsum), vmovl_u16 (special));
}
/* Vector implementation of single-precision hypot.
Maximum error observed is 1.21 ULP:
_ZGVnN4vv_hypotf (0x1.6a419cp-13, 0x1.82a852p-22) got 0x1.6a41d2p-13
want 0x1.6a41dp-13. */
#if WANT_SIMD_EXCEPT
float32x4_t VPCS_ATTR V_NAME_F2 (hypot) (float32x4_t x, float32x4_t y)
{
const struct data *d = ptr_barrier (&data);
float32x4_t ax = vabsq_f32 (x);
float32x4_t ay = vabsq_f32 (y);
uint32x4_t ix = vreinterpretq_u32_f32 (ax);
uint32x4_t iy = vreinterpretq_u32_f32 (ay);
/* Extreme values, NaNs, and infinities should be handled by the scalar
fallback for correct flag handling. */
uint32x4_t specialx = vcgeq_u32 (vsubq_u32 (ix, d->tiny_bound), d->thres);
uint32x4_t specialy = vcgeq_u32 (vsubq_u32 (iy, d->tiny_bound), d->thres);
ax = v_zerofy_f32 (ax, specialx);
ay = v_zerofy_f32 (ay, specialy);
uint16x4_t special = vaddhn_u32 (specialx, specialy);
float32x4_t sqsum = vfmaq_f32 (vmulq_f32 (ax, ax), ay, ay);
if (__glibc_unlikely (v_any_u16h (special)))
return special_case (x, y, sqsum, special);
return vsqrtq_f32 (sqsum);
}
#else
float32x4_t VPCS_ATTR V_NAME_F2 (hypot) (float32x4_t x, float32x4_t y)
{
const struct data *d = ptr_barrier (&data);
float32x4_t sqsum = vfmaq_f32 (vmulq_f32 (x, x), y, y);
uint16x4_t special = vcge_u16 (
vsubhn_u32 (vreinterpretq_u32_f32 (sqsum), d->tiny_bound),
vget_low_u16 (d->thres));
if (__glibc_unlikely (v_any_u16h (special)))
return special_case (x, y, sqsum, special);
return vsqrtq_f32 (sqsum);
}
#endif
libmvec_hidden_def (V_NAME_F2 (hypot))
HALF_WIDTH_ALIAS_F2(hypot)
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