whesse@chromium.org | cec079d | 2010-03-22 14:44:04 +0000 | [diff] [blame] | 1 | // Copyright 2010 the V8 project authors. All rights reserved. |
| 2 | // Redistribution and use in source and binary forms, with or without |
| 3 | // modification, are permitted provided that the following conditions are |
| 4 | // met: |
| 5 | // |
| 6 | // * Redistributions of source code must retain the above copyright |
| 7 | // notice, this list of conditions and the following disclaimer. |
| 8 | // * Redistributions in binary form must reproduce the above |
| 9 | // copyright notice, this list of conditions and the following |
| 10 | // disclaimer in the documentation and/or other materials provided |
| 11 | // with the distribution. |
| 12 | // * Neither the name of Google Inc. nor the names of its |
| 13 | // contributors may be used to endorse or promote products derived |
| 14 | // from this software without specific prior written permission. |
| 15 | // |
| 16 | // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 17 | // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 18 | // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 19 | // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| 20 | // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 21 | // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| 22 | // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 23 | // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 24 | // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 25 | // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| 26 | // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 27 | |
| 28 | #ifndef V8_CACHED_POWERS_H_ |
| 29 | #define V8_CACHED_POWERS_H_ |
| 30 | |
| 31 | #include "diy-fp.h" |
| 32 | |
| 33 | namespace v8 { |
| 34 | namespace internal { |
| 35 | |
lrn@chromium.org | 303ada7 | 2010-10-27 09:33:13 +0000 | [diff] [blame] | 36 | class PowersOfTenCache { |
| 37 | public: |
lrn@chromium.org | 303ada7 | 2010-10-27 09:33:13 +0000 | [diff] [blame] | 38 | // Not all powers of ten are cached. The decimal exponent of two neighboring |
| 39 | // cached numbers will differ by kDecimalExponentDistance. |
| 40 | static const int kDecimalExponentDistance; |
| 41 | |
| 42 | static const int kMinDecimalExponent; |
| 43 | static const int kMaxDecimalExponent; |
| 44 | |
| 45 | // Returns a cached power-of-ten with a binary exponent in the range |
| 46 | // [min_exponent; max_exponent] (boundaries included). |
| 47 | static void GetCachedPowerForBinaryExponentRange(int min_exponent, |
| 48 | int max_exponent, |
| 49 | DiyFp* power, |
| 50 | int* decimal_exponent); |
| 51 | |
| 52 | // Returns a cached power of ten x ~= 10^k such that |
| 53 | // k <= decimal_exponent < k + kCachedPowersDecimalDistance. |
| 54 | // The given decimal_exponent must satisfy |
| 55 | // kMinDecimalExponent <= requested_exponent, and |
| 56 | // requested_exponent < kMaxDecimalExponent + kDecimalExponentDistance. |
| 57 | static void GetCachedPowerForDecimalExponent(int requested_exponent, |
| 58 | DiyFp* power, |
| 59 | int* found_exponent); |
| 60 | }; |
whesse@chromium.org | cec079d | 2010-03-22 14:44:04 +0000 | [diff] [blame] | 61 | |
| 62 | } } // namespace v8::internal |
| 63 | |
| 64 | #endif // V8_CACHED_POWERS_H_ |