forked from OSchip/llvm-project
79 lines
2.6 KiB
C++
79 lines
2.6 KiB
C++
//===-- Properties of floating point numbers --------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_LIBC_UTILS_FPUTIL_FLOAT_PROPERTIES_H
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#define LLVM_LIBC_UTILS_FPUTIL_FLOAT_PROPERTIES_H
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#include <stdint.h>
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namespace __llvm_libc {
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namespace fputil {
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template <typename T> struct FloatProperties {};
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template <> struct FloatProperties<float> {
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typedef uint32_t BitsType;
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static_assert(sizeof(BitsType) == sizeof(float),
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"Unexpected size of 'float' type.");
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static constexpr uint32_t bitWidth = sizeof(BitsType) << 3;
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static constexpr uint32_t mantissaWidth = 23;
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static constexpr BitsType mantissaMask = 0x007fffffU;
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static constexpr BitsType signMask = 0x80000000U;
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static constexpr BitsType exponentMask = ~(signMask | mantissaMask);
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static constexpr uint32_t exponentOffset = 127;
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// If a number x is a NAN, then it is a quiet NAN if:
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// QuietNaNMask & bits(x) != 0
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// Else, it is a signalling NAN.
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static constexpr BitsType quietNaNMask = 0x00400000U;
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};
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template <> struct FloatProperties<double> {
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typedef uint64_t BitsType;
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static_assert(sizeof(BitsType) == sizeof(double),
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"Unexpected size of 'double' type.");
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static constexpr uint32_t bitWidth = sizeof(BitsType) << 3;
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static constexpr uint32_t mantissaWidth = 52;
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static constexpr BitsType mantissaMask = 0x000fffffffffffffU;
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static constexpr BitsType signMask = 0x8000000000000000ULL;
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static constexpr BitsType exponentMask = ~(signMask | mantissaMask);
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static constexpr uint32_t exponentOffset = 1023;
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// If a number x is a NAN, then it is a quiet NAN if:
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// QuietNaNMask & bits(x) != 0
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// Else, it is a signalling NAN.
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static constexpr BitsType quietNaNMask = 0x0008000000000000ULL;
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};
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// Define the float type corresponding to the BitsType.
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template <typename BitsType> struct FloatType;
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template <> struct FloatType<uint32_t> {
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static_assert(sizeof(uint32_t) == sizeof(float),
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"Unexpected size of 'float' type.");
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typedef float Type;
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};
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template <> struct FloatType<uint64_t> {
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static_assert(sizeof(uint64_t) == sizeof(double),
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"Unexpected size of 'double' type.");
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typedef double Type;
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};
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template <typename BitsType>
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using FloatTypeT = typename FloatType<BitsType>::Type;
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} // namespace fputil
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} // namespace __llvm_libc
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#endif // LLVM_LIBC_UTILS_FPUTIL_FLOAT_PROPERTIES_H
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