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Differential D132811 Diff 456755 libc/src/math/generic/atanhf.cpp

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libc/src/math/generic/atanhf.cpp

  • This file was added.
//===-- Single-precision atanh function -----------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "src/math/atanhf.h"
#include "src/__support/FPUtil/FPBits.h"
#include "src/math/generic/supfuncf.h"
namespace __llvm_libc {
LLVM_LIBC_FUNCTION(float, atanhf, (float x)) {
using FPBits = typename fputil::FPBits<float>;
FPBits xbits(x);
bool sign = xbits.get_sign();
uint32_t x_abs = xbits.uintval() & FPBits::FloatProp::EXP_MANT_MASK;
// |x| >= 1.0
if (unlikely(x_abs >= 0x3F80'0000U)) {
lntueUnsubmitted
Done
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|x| >= 1.0 ?

lntue: `|x| >= 1.0` ?
if (xbits.is_nan()) {
return x + 1.0f;
}
// |x| == 0
if (x_abs == 0x3F80'0000U) {
fputil::set_except(FE_DIVBYZERO);
return with_errno(FPBits::inf(sign).get_val(), ERANGE);
} else {
fputil::set_except(FE_INVALID);
return with_errno(
FPBits::build_nan(1 << (fputil::MantissaWidth<float>::VALUE - 1)),
EDOM);
}
}
// |x| < ~0.10
if (unlikely(x_abs <= 0x3dcc'0000U)) {
// |x| <= 2^-26
if (unlikely(x_abs <= 0x3280'0000U)) {
return unlikely(x_abs == 0) ? x : (x + 0x1.5555555555555p-2 * x * x * x);
}
double xdbl = x;
double x2 = xdbl * xdbl;
// Pure Taylor series.
double pe = fputil::polyeval(x2, 0.0, 0x1.5555555555555p-2,
0x1.999999999999ap-3, 0x1.2492492492492p-3,
0x1.c71c71c71c71cp-4, 0x1.745d1745d1746p-4);
return fputil::multiply_add(xdbl, pe, xdbl);
}
double xdbl = x;
return 0.5 * log_eval((xdbl + 1.0) / (xdbl - 1.0));
}
} // namespace __llvm_libc