1 //===-- Basic operations on floating point numbers --------------*- 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_FPUTIL_BASIC_OPERATIONS_H
10 #define LLVM_LIBC_SRC_SUPPORT_FPUTIL_BASIC_OPERATIONS_H
11 
12 #include "FPBits.h"
13 
14 #include "src/__support/CPP/TypeTraits.h"
15 
16 namespace __llvm_libc {
17 namespace fputil {
18 
19 template <typename T,
20           cpp::EnableIfType<cpp::IsFloatingPointType<T>::Value, int> = 0>
21 static inline T abs(T x) {
22   FPBits<T> bits(x);
23   bits.set_sign(0);
24   return T(bits);
25 }
26 
27 template <typename T,
28           cpp::EnableIfType<cpp::IsFloatingPointType<T>::Value, int> = 0>
29 static inline T fmin(T x, T y) {
30   FPBits<T> bitx(x), bity(y);
31 
32   if (bitx.is_nan()) {
33     return y;
34   } else if (bity.is_nan()) {
35     return x;
36   } else if (bitx.get_sign() != bity.get_sign()) {
37     // To make sure that fmin(+0, -0) == -0 == fmin(-0, +0), whenever x and
38     // y has different signs and both are not NaNs, we return the number
39     // with negative sign.
40     return (bitx.get_sign() ? x : y);
41   } else {
42     return (x < y ? x : y);
43   }
44 }
45 
46 template <typename T,
47           cpp::EnableIfType<cpp::IsFloatingPointType<T>::Value, int> = 0>
48 static inline T fmax(T x, T y) {
49   FPBits<T> bitx(x), bity(y);
50 
51   if (bitx.is_nan()) {
52     return y;
53   } else if (bity.is_nan()) {
54     return x;
55   } else if (bitx.get_sign() != bity.get_sign()) {
56     // To make sure that fmax(+0, -0) == +0 == fmax(-0, +0), whenever x and
57     // y has different signs and both are not NaNs, we return the number
58     // with positive sign.
59     return (bitx.get_sign() ? y : x);
60   } else {
61     return (x > y ? x : y);
62   }
63 }
64 
65 template <typename T,
66           cpp::EnableIfType<cpp::IsFloatingPointType<T>::Value, int> = 0>
67 static inline T fdim(T x, T y) {
68   FPBits<T> bitx(x), bity(y);
69 
70   if (bitx.is_nan()) {
71     return x;
72   }
73 
74   if (bity.is_nan()) {
75     return y;
76   }
77 
78   return (x > y ? x - y : 0);
79 }
80 
81 } // namespace fputil
82 } // namespace __llvm_libc
83 
84 #endif // LLVM_LIBC_SRC_SUPPORT_FPUTIL_BASIC_OPERATIONS_H
85