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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 |
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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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