xref: /aosp_15_r20/external/llvm-libc/src/math/generic/sinhf.cpp (revision 71db0c75aadcf003ffe3238005f61d7618a3fead)
1 //===-- Single-precision sinh function ------------------------------------===//
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 #include "src/math/sinhf.h"
10 #include "src/__support/FPUtil/FPBits.h"
11 #include "src/__support/FPUtil/rounding_mode.h"
12 #include "src/__support/macros/config.h"
13 #include "src/__support/macros/optimization.h" // LIBC_UNLIKELY
14 #include "src/math/generic/explogxf.h"
15 
16 namespace LIBC_NAMESPACE_DECL {
17 
18 LLVM_LIBC_FUNCTION(float, sinhf, (float x)) {
19   using FPBits = typename fputil::FPBits<float>;
20   FPBits xbits(x);
21   uint32_t x_abs = xbits.abs().uintval();
22 
23   // When |x| >= 90, or x is inf or nan
24   if (LIBC_UNLIKELY(x_abs >= 0x42b4'0000U || x_abs <= 0x3da0'0000U)) {
25     // |x| <= 0.078125
26     if (x_abs <= 0x3da0'0000U) {
27       // |x| = 0.0005589424981735646724700927734375
28       if (LIBC_UNLIKELY(x_abs == 0x3a12'85ffU)) {
29         if (fputil::fenv_is_round_to_nearest())
30           return x;
31       }
32 
33       // |x| <= 2^-26
34       if (LIBC_UNLIKELY(x_abs <= 0x3280'0000U)) {
35         return static_cast<float>(
36             LIBC_UNLIKELY(x_abs == 0) ? x : (x + 0.25 * x * x * x));
37       }
38 
39       double xdbl = x;
40       double x2 = xdbl * xdbl;
41       // Sollya: fpminimax(sinh(x),[|3,5,7|],[|D...|],[-1/16-1/64;1/16+1/64],x);
42       // Sollya output: x * (0x1p0 + x^0x1p1 * (0x1.5555555556583p-3 + x^0x1p1
43       //                  * (0x1.111110d239f1fp-7
44       //                  + x^0x1p1 * 0x1.a02b5a284013cp-13)))
45       // Therefore, output of Sollya = x * pe;
46       double pe = fputil::polyeval(x2, 0.0, 0x1.5555555556583p-3,
47                                    0x1.111110d239f1fp-7, 0x1.a02b5a284013cp-13);
48       return static_cast<float>(fputil::multiply_add(xdbl, pe, xdbl));
49     }
50 
51     if (xbits.is_nan())
52       return x + 1.0f; // sNaN to qNaN + signal
53 
54     if (xbits.is_inf())
55       return x;
56 
57     int rounding = fputil::quick_get_round();
58     if (xbits.is_neg()) {
59       if (LIBC_UNLIKELY(rounding == FE_UPWARD || rounding == FE_TOWARDZERO))
60         return -FPBits::max_normal().get_val();
61     } else {
62       if (LIBC_UNLIKELY(rounding == FE_DOWNWARD || rounding == FE_TOWARDZERO))
63         return FPBits::max_normal().get_val();
64     }
65 
66     fputil::set_errno_if_required(ERANGE);
67     fputil::raise_except_if_required(FE_OVERFLOW);
68 
69     return x + FPBits::inf(xbits.sign()).get_val();
70   }
71 
72   // sinh(x) = (e^x - e^(-x)) / 2.
73   return static_cast<float>(exp_pm_eval</*is_sinh*/ true>(x));
74 }
75 
76 } // namespace LIBC_NAMESPACE_DECL
77