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1 // Copyright 2010 the V8 project authors. All rights reserved. | 1 // Copyright 2010 the V8 project authors. All rights reserved. |
2 // Redistribution and use in source and binary forms, with or without | 2 // Redistribution and use in source and binary forms, with or without |
3 // modification, are permitted provided that the following conditions are | 3 // modification, are permitted provided that the following conditions are |
4 // met: | 4 // met: |
5 // | 5 // |
6 // * Redistributions of source code must retain the above copyright | 6 // * Redistributions of source code must retain the above copyright |
7 // notice, this list of conditions and the following disclaimer. | 7 // notice, this list of conditions and the following disclaimer. |
8 // * Redistributions in binary form must reproduce the above | 8 // * Redistributions in binary form must reproduce the above |
9 // copyright notice, this list of conditions and the following | 9 // copyright notice, this list of conditions and the following |
10 // disclaimer in the documentation and/or other materials provided | 10 // disclaimer in the documentation and/or other materials provided |
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26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | 26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
27 | 27 |
28 #ifndef V8_CACHED_POWERS_H_ | 28 #ifndef V8_CACHED_POWERS_H_ |
29 #define V8_CACHED_POWERS_H_ | 29 #define V8_CACHED_POWERS_H_ |
30 | 30 |
31 #include "diy-fp.h" | 31 #include "diy-fp.h" |
32 | 32 |
33 namespace v8 { | 33 namespace v8 { |
34 namespace internal { | 34 namespace internal { |
35 | 35 |
36 void GetCachedPowerForBinaryExponentRange(int min_exponent, | 36 class PowersOfTenCache { |
37 int max_exponent, | 37 public: |
38 DiyFp* power, | 38 |
39 int* decimal_exponent); | 39 // Not all powers of ten are cached. The decimal exponent of two neighboring |
| 40 // cached numbers will differ by kDecimalExponentDistance. |
| 41 static const int kDecimalExponentDistance; |
| 42 |
| 43 static const int kMinDecimalExponent; |
| 44 static const int kMaxDecimalExponent; |
| 45 |
| 46 // Returns a cached power-of-ten with a binary exponent in the range |
| 47 // [min_exponent; max_exponent] (boundaries included). |
| 48 static void GetCachedPowerForBinaryExponentRange(int min_exponent, |
| 49 int max_exponent, |
| 50 DiyFp* power, |
| 51 int* decimal_exponent); |
| 52 |
| 53 // Returns a cached power of ten x ~= 10^k such that |
| 54 // k <= decimal_exponent < k + kCachedPowersDecimalDistance. |
| 55 // The given decimal_exponent must satisfy |
| 56 // kMinDecimalExponent <= requested_exponent, and |
| 57 // requested_exponent < kMaxDecimalExponent + kDecimalExponentDistance. |
| 58 static void GetCachedPowerForDecimalExponent(int requested_exponent, |
| 59 DiyFp* power, |
| 60 int* found_exponent); |
| 61 }; |
40 | 62 |
41 } } // namespace v8::internal | 63 } } // namespace v8::internal |
42 | 64 |
43 #endif // V8_CACHED_POWERS_H_ | 65 #endif // V8_CACHED_POWERS_H_ |
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