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//===-- Single-precision cosh 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/coshf.h"
#include "src/__support/FPUtil/FPBits.h"
#include "src/__support/FPUtil/multiply_add.h"
#include "src/__support/FPUtil/rounding_mode.h"
#include "src/__support/macros/optimization.h" // LIBC_UNLIKELY
#include "src/math/generic/explogxf.h"
namespace __llvm_libc {
LLVM_LIBC_FUNCTION(float, coshf, (float x)) {
using FPBits = typename fputil::FPBits<float>;
FPBits xbits(x);
xbits.set_sign(false);
x = xbits.get_val();
uint32_t x_u = xbits.uintval();
// When |x| >= 90, or x is inf or nan
if (LIBC_UNLIKELY(x_u >= 0x42b4'0000U || x_u <= 0x3280'0000U)) {
// |x| <= 2^-26
if (x_u <= 0x3280'0000U) {
return 1.0f + x;
}
if (xbits.is_inf_or_nan())
return x + FPBits::inf().get_val();
int rounding = fputil::quick_get_round();
if (LIBC_UNLIKELY(rounding == FE_DOWNWARD || rounding == FE_TOWARDZERO))
return FPBits(FPBits::MAX_NORMAL).get_val();
fputil::set_errno_if_required(ERANGE);
fputil::raise_except_if_required(FE_OVERFLOW);
return x + FPBits::inf().get_val();
}
// TODO: We should be able to reduce the latency and reciprocal throughput
// further by using a low degree (maybe 3-7 ?) minimax polynomial for small
// but not too small inputs, such as |x| < 2^-2, or |x| < 2^-3.
// cosh(x) = (e^x + e^(-x)) / 2.
return static_cast<float>(exp_pm_eval</*is_sinh*/ false>(x));
}
} // namespace __llvm_libc
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