libc/src/__support/FPUtil/BasicOperations.h

   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/type_traits.h"
  15 #include "src/__support/common.h"
  16
  17 namespace __llvm_libc {
  18 namespace fputil {
  19
  20 template <typename T, cpp::enable_if_t<cpp::is_floating_point_v<T>, int> = 0>
  21 LIBC_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, cpp::enable_if_t<cpp::is_floating_point_v<T>, int> = 0>
  28 LIBC_INLINE T fmin(T x, T y) {
  29   FPBits<T> bitx(x), bity(y);
  30
  31   if (bitx.is_nan()) {
  32     return y;
  33   } else if (bity.is_nan()) {
  34     return x;
  35   } else if (bitx.get_sign() != bity.get_sign()) {
  36     // To make sure that fmin(+0, -0) == -0 == fmin(-0, +0), whenever x and
  37     // y has different signs and both are not NaNs, we return the number
  38     // with negative sign.
  39     return (bitx.get_sign() ? x : y);
  40   } else {
  41     return (x < y ? x : y);
  42   }
  43 }
  44
  45 template <typename T, cpp::enable_if_t<cpp::is_floating_point_v<T>, int> = 0>
  46 LIBC_INLINE T fmax(T x, T y) {
  47   FPBits<T> bitx(x), bity(y);
  48
  49   if (bitx.is_nan()) {
  50     return y;
  51   } else if (bity.is_nan()) {
  52     return x;
  53   } else if (bitx.get_sign() != bity.get_sign()) {
  54     // To make sure that fmax(+0, -0) == +0 == fmax(-0, +0), whenever x and
  55     // y has different signs and both are not NaNs, we return the number
  56     // with positive sign.
  57     return (bitx.get_sign() ? y : x);
  58   } else {
  59     return (x > y ? x : y);
  60   }
  61 }
  62
  63 template <typename T, cpp::enable_if_t<cpp::is_floating_point_v<T>, int> = 0>
  64 LIBC_INLINE T fdim(T x, T y) {
  65   FPBits<T> bitx(x), bity(y);
  66
  67   if (bitx.is_nan()) {
  68     return x;
  69   }
  70
  71   if (bity.is_nan()) {
  72     return y;
  73   }
  74
  75   return (x > y ? x - y : 0);
  76 }
  77
  78 } // namespace fputil
  79 } // namespace __llvm_libc
  80
  81 #endif // LLVM_LIBC_SRC_SUPPORT_FPUTIL_BASIC_OPERATIONS_H