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/* Double-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
{
uint64x2_t tiny_bound, thres;
} data = {
.tiny_bound = V2 (0x2000000000000000), /* asuint (0x1p-511). */
.thres = V2 (0x3fe0000000000000), /* asuint (0x1p511) - tiny_bound. */
};
#else
static const struct data
{
uint64x2_t tiny_bound;
uint32x4_t thres;
} data = {
.tiny_bound = V2 (0x0360000000000000), /* asuint (0x1p-969). */
.thres = V4 (0x7c900000), /* asuint (inf) - tiny_bound. */
};
#endif
static float64x2_t VPCS_ATTR NOINLINE
special_case (float64x2_t x, float64x2_t y, float64x2_t sqsum,
uint32x2_t special)
{
return v_call2_f64 (hypot, x, y, vsqrtq_f64 (sqsum), vmovl_u32 (special));
}
/* Vector implementation of double-precision hypot.
Maximum error observed is 1.21 ULP:
_ZGVnN2vv_hypot (0x1.6a1b193ff85b5p-204, 0x1.bc50676c2a447p-222)
got 0x1.6a1b19400964ep-204
want 0x1.6a1b19400964dp-204. */
#if WANT_SIMD_EXCEPT
float64x2_t VPCS_ATTR V_NAME_D2 (hypot) (float64x2_t x, float64x2_t y)
{
const struct data *d = ptr_barrier (&data);
float64x2_t ax = vabsq_f64 (x);
float64x2_t ay = vabsq_f64 (y);
uint64x2_t ix = vreinterpretq_u64_f64 (ax);
uint64x2_t iy = vreinterpretq_u64_f64 (ay);
/* Extreme values, NaNs, and infinities should be handled by the scalar
fallback for correct flag handling. */
uint64x2_t specialx = vcgeq_u64 (vsubq_u64 (ix, d->tiny_bound), d->thres);
uint64x2_t specialy = vcgeq_u64 (vsubq_u64 (iy, d->tiny_bound), d->thres);
ax = v_zerofy_f64 (ax, specialx);
ay = v_zerofy_f64 (ay, specialy);
uint32x2_t special = vaddhn_u64 (specialx, specialy);
float64x2_t sqsum = vfmaq_f64 (vmulq_f64 (ax, ax), ay, ay);
if (__glibc_unlikely (v_any_u32h (special)))
return special_case (x, y, sqsum, special);
return vsqrtq_f64 (sqsum);
}
#else
float64x2_t VPCS_ATTR V_NAME_D2 (hypot) (float64x2_t x, float64x2_t y)
{
const struct data *d = ptr_barrier (&data);
float64x2_t sqsum = vfmaq_f64 (vmulq_f64 (x, x), y, y);
uint32x2_t special = vcge_u32 (
vsubhn_u64 (vreinterpretq_u64_f64 (sqsum), d->tiny_bound),
vget_low_u32 (d->thres));
if (__glibc_unlikely (v_any_u32h (special)))
return special_case (x, y, sqsum, special);
return vsqrtq_f64 (sqsum);
}
#endif
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