1//===-- Implementation header for coshf -------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef LLVM_LIBC_SRC___SUPPORT_MATH_COSHF_H
10#define LLVM_LIBC_SRC___SUPPORT_MATH_COSHF_H
11
12#include "sinhfcoshf_utils.h"
13#include "src/__support/FPUtil/FEnvImpl.h"
14#include "src/__support/FPUtil/FPBits.h"
15#include "src/__support/FPUtil/rounding_mode.h"
16#include "src/__support/macros/config.h"
17#include "src/__support/macros/optimization.h" // LIBC_UNLIKELY
18
19namespace LIBC_NAMESPACE_DECL {
20
21namespace math {
22
23LIBC_INLINE float coshf(float x) {
24 using namespace sinhfcoshf_internal;
25 using FPBits = typename fputil::FPBits<float>;
26
27 FPBits xbits(x);
28 xbits.set_sign(Sign::POS);
29 x = xbits.get_val();
30
31 uint32_t x_u = xbits.uintval();
32
33 // When |x| >= 90, or x is inf or nan
34 if (LIBC_UNLIKELY(x_u >= 0x42b4'0000U || x_u <= 0x3280'0000U)) {
35 // |x| <= 2^-26
36 if (x_u <= 0x3280'0000U) {
37 return 1.0f + x;
38 }
39
40 if (xbits.is_inf_or_nan())
41 return x + FPBits::inf().get_val();
42
43#ifndef LIBC_MATH_HAS_ASSUME_ROUND_NEAREST_ONLY
44 int rounding = fputil::quick_get_round();
45 if (LIBC_UNLIKELY(rounding == FE_DOWNWARD || rounding == FE_TOWARDZERO))
46 return FPBits::max_normal().get_val();
47#endif
48
49 fputil::set_errno_if_required(ERANGE);
50 fputil::raise_except_if_required(FE_OVERFLOW);
51
52 return x + FPBits::inf().get_val();
53 }
54
55 // TODO: We should be able to reduce the latency and reciprocal throughput
56 // further by using a low degree (maybe 3-7 ?) minimax polynomial for small
57 // but not too small inputs, such as |x| < 2^-2, or |x| < 2^-3.
58
59 // cosh(x) = (e^x + e^(-x)) / 2.
60 return static_cast<float>(exp_pm_eval</*is_sinh*/ false>(x));
61}
62
63} // namespace math
64
65} // namespace LIBC_NAMESPACE_DECL
66
67#endif // LLVM_LIBC_SRC___SUPPORT_MATH_COSHF_H
68