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| 1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file | 1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file |
| 2 // for details. All rights reserved. Use of this source code is governed by a | 2 // for details. All rights reserved. Use of this source code is governed by a |
| 3 // BSD-style license that can be found in the LICENSE file. | 3 // BSD-style license that can be found in the LICENSE file. |
| 4 | 4 |
| 5 #ifndef RUNTIME_VM_DOUBLE_INTERNALS_H_ | 5 #ifndef RUNTIME_VM_DOUBLE_INTERNALS_H_ |
| 6 #define RUNTIME_VM_DOUBLE_INTERNALS_H_ | 6 #define RUNTIME_VM_DOUBLE_INTERNALS_H_ |
| 7 | 7 |
| 8 #include "platform/utils.h" | 8 #include "platform/utils.h" |
| 9 | 9 |
| 10 namespace dart { | 10 namespace dart { |
| 11 | 11 |
| 12 // We assume that doubles and uint64_t have the same endianness. | 12 // We assume that doubles and uint64_t have the same endianness. |
| 13 static uint64_t double_to_uint64(double d) { return bit_cast<uint64_t>(d); } | 13 static uint64_t double_to_uint64(double d) { |
| 14 return bit_cast<uint64_t>(d); |
| 15 } |
| 14 | 16 |
| 15 // Helper functions for doubles. | 17 // Helper functions for doubles. |
| 16 class DoubleInternals { | 18 class DoubleInternals { |
| 17 public: | 19 public: |
| 18 static const int kSignificandSize = 53; | 20 static const int kSignificandSize = 53; |
| 19 | 21 |
| 20 explicit DoubleInternals(double d) : d64_(double_to_uint64(d)) {} | 22 explicit DoubleInternals(double d) : d64_(double_to_uint64(d)) {} |
| 21 | 23 |
| 22 // Returns the double's bit as uint64. | 24 // Returns the double's bit as uint64. |
| 23 uint64_t AsUint64() const { | 25 uint64_t AsUint64() const { return d64_; } |
| 24 return d64_; | |
| 25 } | |
| 26 | 26 |
| 27 int Exponent() const { | 27 int Exponent() const { |
| 28 if (IsDenormal()) return kDenormalExponent; | 28 if (IsDenormal()) return kDenormalExponent; |
| 29 | 29 |
| 30 uint64_t d64 = AsUint64(); | 30 uint64_t d64 = AsUint64(); |
| 31 int biased_e = | 31 int biased_e = |
| 32 static_cast<int>((d64 & kExponentMask) >> kPhysicalSignificandSize); | 32 static_cast<int>((d64 & kExponentMask) >> kPhysicalSignificandSize); |
| 33 return biased_e - kExponentBias; | 33 return biased_e - kExponentBias; |
| 34 } | 34 } |
| 35 | 35 |
| (...skipping 15 matching lines...) Expand all Loading... |
| 51 | 51 |
| 52 // We consider denormals not to be special. | 52 // We consider denormals not to be special. |
| 53 // Hence only Infinity and NaN are special. | 53 // Hence only Infinity and NaN are special. |
| 54 bool IsSpecial() const { | 54 bool IsSpecial() const { |
| 55 uint64_t d64 = AsUint64(); | 55 uint64_t d64 = AsUint64(); |
| 56 return (d64 & kExponentMask) == kExponentMask; | 56 return (d64 & kExponentMask) == kExponentMask; |
| 57 } | 57 } |
| 58 | 58 |
| 59 int Sign() const { | 59 int Sign() const { |
| 60 uint64_t d64 = AsUint64(); | 60 uint64_t d64 = AsUint64(); |
| 61 return (d64 & kSignMask) == 0? 1: -1; | 61 return (d64 & kSignMask) == 0 ? 1 : -1; |
| 62 } | 62 } |
| 63 | 63 |
| 64 private: | 64 private: |
| 65 static const uint64_t kSignMask = DART_2PART_UINT64_C(0x80000000, 00000000); | 65 static const uint64_t kSignMask = DART_2PART_UINT64_C(0x80000000, 00000000); |
| 66 static const uint64_t kExponentMask = | 66 static const uint64_t kExponentMask = |
| 67 DART_2PART_UINT64_C(0x7FF00000, 00000000); | 67 DART_2PART_UINT64_C(0x7FF00000, 00000000); |
| 68 static const uint64_t kSignificandMask = | 68 static const uint64_t kSignificandMask = |
| 69 DART_2PART_UINT64_C(0x000FFFFF, FFFFFFFF); | 69 DART_2PART_UINT64_C(0x000FFFFF, FFFFFFFF); |
| 70 static const uint64_t kHiddenBit = DART_2PART_UINT64_C(0x00100000, 00000000); | 70 static const uint64_t kHiddenBit = DART_2PART_UINT64_C(0x00100000, 00000000); |
| 71 static const int kPhysicalSignificandSize = 52; // Excludes the hidden bit. | 71 static const int kPhysicalSignificandSize = 52; // Excludes the hidden bit. |
| 72 static const int kExponentBias = 0x3FF + kPhysicalSignificandSize; | 72 static const int kExponentBias = 0x3FF + kPhysicalSignificandSize; |
| 73 static const int kDenormalExponent = -kExponentBias + 1; | 73 static const int kDenormalExponent = -kExponentBias + 1; |
| 74 | 74 |
| 75 const uint64_t d64_; | 75 const uint64_t d64_; |
| 76 }; | 76 }; |
| 77 | 77 |
| 78 } // namespace dart | 78 } // namespace dart |
| 79 | 79 |
| 80 #endif // RUNTIME_VM_DOUBLE_INTERNALS_H_ | 80 #endif // RUNTIME_VM_DOUBLE_INTERNALS_H_ |
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