1 //===-- Single-precision acosh 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/acoshf.h" 10 #include "src/__support/FPUtil/FEnvImpl.h" 11 #include "src/__support/FPUtil/FPBits.h" 12 #include "src/__support/FPUtil/PolyEval.h" 13 #include "src/__support/FPUtil/multiply_add.h" 14 #include "src/__support/FPUtil/sqrt.h" 15 #include "src/__support/macros/optimization.h" // LIBC_UNLIKELY 16 #include "src/math/generic/common_constants.h" 17 #include "src/math/generic/explogxf.h" 18 19 namespace LIBC_NAMESPACE { 20 21 LLVM_LIBC_FUNCTION(float, acoshf, (float x)) { 22 using FPBits_t = typename fputil::FPBits<float>; 23 FPBits_t xbits(x); 24 uint32_t x_u = xbits.uintval(); 25 26 if (LIBC_UNLIKELY(x <= 1.0f)) { 27 if (x == 1.0f) 28 return 0.0f; 29 // x < 1. 30 fputil::set_errno_if_required(EDOM); 31 fputil::raise_except_if_required(FE_INVALID); 32 return FPBits_t::quiet_nan().get_val(); 33 } 34 35 if (LIBC_UNLIKELY(x_u >= 0x4f8ffb03)) { 36 if (LIBC_UNLIKELY(xbits.is_inf_or_nan())) 37 return x; 38 39 // Helper functions to set results for exceptional cases. __anona71a0f770102(float r) 40 auto round_result_slightly_down = [](float r) -> float { 41 volatile float tmp = r; 42 tmp = tmp - 0x1.0p-25f; 43 return tmp; 44 }; __anona71a0f770202(float r) 45 auto round_result_slightly_up = [](float r) -> float { 46 volatile float tmp = r; 47 tmp = tmp + 0x1.0p-25f; 48 return tmp; 49 }; 50 51 switch (x_u) { 52 case 0x4f8ffb03: // x = 0x1.1ff606p32f 53 return round_result_slightly_up(0x1.6fdd34p4f); 54 case 0x5c569e88: // x = 0x1.ad3d1p57f 55 return round_result_slightly_up(0x1.45c146p5f); 56 case 0x5e68984e: // x = 0x1.d1309cp61f 57 return round_result_slightly_up(0x1.5c9442p5f); 58 case 0x655890d3: // x = 0x1.b121a6p75f 59 return round_result_slightly_down(0x1.a9a3f2p5f); 60 case 0x6eb1a8ec: // x = 0x1.6351d8p94f 61 return round_result_slightly_down(0x1.08b512p6f); 62 case 0x7997f30a: // x = 0x1.2fe614p116f 63 return round_result_slightly_up(0x1.451436p6f); 64 } 65 } 66 67 double x_d = static_cast<double>(x); 68 // acosh(x) = log(x + sqrt(x^2 - 1)) 69 return static_cast<float>( 70 log_eval(x_d + fputil::sqrt(fputil::multiply_add(x_d, x_d, -1.0)))); 71 } 72 73 } // namespace LIBC_NAMESPACE 74