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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 #include "platform/utils.h" | 5 #include "platform/utils.h" |
6 | 6 |
7 namespace dart { | 7 namespace dart { |
8 | 8 |
9 // Implementation is from "Hacker's Delight" by Henry S. Warren, Jr., | 9 // Implementation is from "Hacker's Delight" by Henry S. Warren, Jr., |
10 // figure 3-3, page 48, where the function is called clp2. | 10 // figure 3-3, page 48, where the function is called clp2. |
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85 | 85 |
86 // Do a few final mixes of the hash to ensure the last few bytes are | 86 // Do a few final mixes of the hash to ensure the last few bytes are |
87 // well-incorporated. | 87 // well-incorporated. |
88 hash ^= hash >> 13; | 88 hash ^= hash >> 13; |
89 hash *= M; | 89 hash *= M; |
90 hash ^= hash >> 15; | 90 hash ^= hash >> 15; |
91 return hash; | 91 return hash; |
92 } | 92 } |
93 | 93 |
94 | 94 |
95 uint32_t Utils::WordHash(word key) { | 95 uint32_t Utils::WordHash(intptr_t key) { |
96 // TODO(iposva): Need to check hash spreading. | 96 // TODO(iposva): Need to check hash spreading. |
97 // This example is from http://www.concentric.net/~Ttwang/tech/inthash.htm | 97 // This example is from http://www.concentric.net/~Ttwang/tech/inthash.htm |
98 uword a = static_cast<uword>(key); | 98 uword a = static_cast<uword>(key); |
99 a = (a + 0x7ed55d16) + (a << 12); | 99 a = (a + 0x7ed55d16) + (a << 12); |
100 a = (a ^ 0xc761c23c) ^ (a >> 19); | 100 a = (a ^ 0xc761c23c) ^ (a >> 19); |
101 a = (a + 0x165667b1) + (a << 5); | 101 a = (a + 0x165667b1) + (a << 5); |
102 a = (a + 0xd3a2646c) ^ (a << 9); | 102 a = (a + 0xd3a2646c) ^ (a << 9); |
103 a = (a + 0xfd7046c5) + (a << 3); | 103 a = (a + 0xfd7046c5) + (a << 3); |
104 a = (a ^ 0xb55a4f09) ^ (a >> 16); | 104 a = (a ^ 0xb55a4f09) ^ (a >> 16); |
105 return static_cast<uint32_t>(a); | 105 return static_cast<uint32_t>(a); |
106 } | 106 } |
107 | 107 |
108 | 108 |
109 } // namespace dart | 109 } // namespace dart |
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