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/* Single-precision vector (SVE) acosh function
Copyright (C) 2024-2025 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 "sv_math.h"
#include "sv_log1pf_inline.h"
#define One 0x3f800000
#define Thres 0x20000000 /* asuint(0x1p64) - One. */
static svfloat32_t NOINLINE
special_case (svfloat32_t xm1, svfloat32_t tmp, svbool_t special)
{
svfloat32_t x = svadd_x (svptrue_b32 (), xm1, 1.0f);
svfloat32_t y = sv_log1pf_inline (tmp, svptrue_b32 ());
return sv_call_f32 (acoshf, x, y, special);
}
/* Single-precision SVE acosh(x) routine. Implements the same algorithm as
vector acoshf and log1p.
Maximum error is 2.47 ULPs:
SV_NAME_F1 (acosh) (0x1.01ca76p+0) got 0x1.e435a6p-4
want 0x1.e435a2p-4. */
svfloat32_t SV_NAME_F1 (acosh) (svfloat32_t x, const svbool_t pg)
{
svuint32_t ix = svreinterpret_u32 (x);
svbool_t special = svcmpge (pg, svsub_x (pg, ix, One), Thres);
svfloat32_t xm1 = svsub_x (pg, x, 1.0f);
svfloat32_t u = svmul_x (pg, xm1, svadd_x (pg, x, 1.0f));
svfloat32_t tmp = svadd_x (pg, xm1, svsqrt_x (pg, u));
if (__glibc_unlikely (svptest_any (pg, special)))
return special_case (xm1, tmp, special);
return sv_log1pf_inline (tmp, pg);
}
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