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