1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/mfbt/double-conversion/cached-powers.cc Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,175 @@
1.4 +// Copyright 2006-2008 the V8 project authors. All rights reserved.
1.5 +// Redistribution and use in source and binary forms, with or without
1.6 +// modification, are permitted provided that the following conditions are
1.7 +// met:
1.8 +//
1.9 +// * Redistributions of source code must retain the above copyright
1.10 +// notice, this list of conditions and the following disclaimer.
1.11 +// * Redistributions in binary form must reproduce the above
1.12 +// copyright notice, this list of conditions and the following
1.13 +// disclaimer in the documentation and/or other materials provided
1.14 +// with the distribution.
1.15 +// * Neither the name of Google Inc. nor the names of its
1.16 +// contributors may be used to endorse or promote products derived
1.17 +// from this software without specific prior written permission.
1.18 +//
1.19 +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
1.20 +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
1.21 +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
1.22 +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
1.23 +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
1.24 +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
1.25 +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
1.26 +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
1.27 +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
1.28 +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
1.29 +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.30 +
1.31 +#include <stdarg.h>
1.32 +#include <limits.h>
1.33 +#include <math.h>
1.34 +
1.35 +#include "utils.h"
1.36 +
1.37 +#include "cached-powers.h"
1.38 +
1.39 +namespace double_conversion {
1.40 +
1.41 +struct CachedPower {
1.42 + uint64_t significand;
1.43 + int16_t binary_exponent;
1.44 + int16_t decimal_exponent;
1.45 +};
1.46 +
1.47 +static const CachedPower kCachedPowers[] = {
1.48 + {UINT64_2PART_C(0xfa8fd5a0, 081c0288), -1220, -348},
1.49 + {UINT64_2PART_C(0xbaaee17f, a23ebf76), -1193, -340},
1.50 + {UINT64_2PART_C(0x8b16fb20, 3055ac76), -1166, -332},
1.51 + {UINT64_2PART_C(0xcf42894a, 5dce35ea), -1140, -324},
1.52 + {UINT64_2PART_C(0x9a6bb0aa, 55653b2d), -1113, -316},
1.53 + {UINT64_2PART_C(0xe61acf03, 3d1a45df), -1087, -308},
1.54 + {UINT64_2PART_C(0xab70fe17, c79ac6ca), -1060, -300},
1.55 + {UINT64_2PART_C(0xff77b1fc, bebcdc4f), -1034, -292},
1.56 + {UINT64_2PART_C(0xbe5691ef, 416bd60c), -1007, -284},
1.57 + {UINT64_2PART_C(0x8dd01fad, 907ffc3c), -980, -276},
1.58 + {UINT64_2PART_C(0xd3515c28, 31559a83), -954, -268},
1.59 + {UINT64_2PART_C(0x9d71ac8f, ada6c9b5), -927, -260},
1.60 + {UINT64_2PART_C(0xea9c2277, 23ee8bcb), -901, -252},
1.61 + {UINT64_2PART_C(0xaecc4991, 4078536d), -874, -244},
1.62 + {UINT64_2PART_C(0x823c1279, 5db6ce57), -847, -236},
1.63 + {UINT64_2PART_C(0xc2109436, 4dfb5637), -821, -228},
1.64 + {UINT64_2PART_C(0x9096ea6f, 3848984f), -794, -220},
1.65 + {UINT64_2PART_C(0xd77485cb, 25823ac7), -768, -212},
1.66 + {UINT64_2PART_C(0xa086cfcd, 97bf97f4), -741, -204},
1.67 + {UINT64_2PART_C(0xef340a98, 172aace5), -715, -196},
1.68 + {UINT64_2PART_C(0xb23867fb, 2a35b28e), -688, -188},
1.69 + {UINT64_2PART_C(0x84c8d4df, d2c63f3b), -661, -180},
1.70 + {UINT64_2PART_C(0xc5dd4427, 1ad3cdba), -635, -172},
1.71 + {UINT64_2PART_C(0x936b9fce, bb25c996), -608, -164},
1.72 + {UINT64_2PART_C(0xdbac6c24, 7d62a584), -582, -156},
1.73 + {UINT64_2PART_C(0xa3ab6658, 0d5fdaf6), -555, -148},
1.74 + {UINT64_2PART_C(0xf3e2f893, dec3f126), -529, -140},
1.75 + {UINT64_2PART_C(0xb5b5ada8, aaff80b8), -502, -132},
1.76 + {UINT64_2PART_C(0x87625f05, 6c7c4a8b), -475, -124},
1.77 + {UINT64_2PART_C(0xc9bcff60, 34c13053), -449, -116},
1.78 + {UINT64_2PART_C(0x964e858c, 91ba2655), -422, -108},
1.79 + {UINT64_2PART_C(0xdff97724, 70297ebd), -396, -100},
1.80 + {UINT64_2PART_C(0xa6dfbd9f, b8e5b88f), -369, -92},
1.81 + {UINT64_2PART_C(0xf8a95fcf, 88747d94), -343, -84},
1.82 + {UINT64_2PART_C(0xb9447093, 8fa89bcf), -316, -76},
1.83 + {UINT64_2PART_C(0x8a08f0f8, bf0f156b), -289, -68},
1.84 + {UINT64_2PART_C(0xcdb02555, 653131b6), -263, -60},
1.85 + {UINT64_2PART_C(0x993fe2c6, d07b7fac), -236, -52},
1.86 + {UINT64_2PART_C(0xe45c10c4, 2a2b3b06), -210, -44},
1.87 + {UINT64_2PART_C(0xaa242499, 697392d3), -183, -36},
1.88 + {UINT64_2PART_C(0xfd87b5f2, 8300ca0e), -157, -28},
1.89 + {UINT64_2PART_C(0xbce50864, 92111aeb), -130, -20},
1.90 + {UINT64_2PART_C(0x8cbccc09, 6f5088cc), -103, -12},
1.91 + {UINT64_2PART_C(0xd1b71758, e219652c), -77, -4},
1.92 + {UINT64_2PART_C(0x9c400000, 00000000), -50, 4},
1.93 + {UINT64_2PART_C(0xe8d4a510, 00000000), -24, 12},
1.94 + {UINT64_2PART_C(0xad78ebc5, ac620000), 3, 20},
1.95 + {UINT64_2PART_C(0x813f3978, f8940984), 30, 28},
1.96 + {UINT64_2PART_C(0xc097ce7b, c90715b3), 56, 36},
1.97 + {UINT64_2PART_C(0x8f7e32ce, 7bea5c70), 83, 44},
1.98 + {UINT64_2PART_C(0xd5d238a4, abe98068), 109, 52},
1.99 + {UINT64_2PART_C(0x9f4f2726, 179a2245), 136, 60},
1.100 + {UINT64_2PART_C(0xed63a231, d4c4fb27), 162, 68},
1.101 + {UINT64_2PART_C(0xb0de6538, 8cc8ada8), 189, 76},
1.102 + {UINT64_2PART_C(0x83c7088e, 1aab65db), 216, 84},
1.103 + {UINT64_2PART_C(0xc45d1df9, 42711d9a), 242, 92},
1.104 + {UINT64_2PART_C(0x924d692c, a61be758), 269, 100},
1.105 + {UINT64_2PART_C(0xda01ee64, 1a708dea), 295, 108},
1.106 + {UINT64_2PART_C(0xa26da399, 9aef774a), 322, 116},
1.107 + {UINT64_2PART_C(0xf209787b, b47d6b85), 348, 124},
1.108 + {UINT64_2PART_C(0xb454e4a1, 79dd1877), 375, 132},
1.109 + {UINT64_2PART_C(0x865b8692, 5b9bc5c2), 402, 140},
1.110 + {UINT64_2PART_C(0xc83553c5, c8965d3d), 428, 148},
1.111 + {UINT64_2PART_C(0x952ab45c, fa97a0b3), 455, 156},
1.112 + {UINT64_2PART_C(0xde469fbd, 99a05fe3), 481, 164},
1.113 + {UINT64_2PART_C(0xa59bc234, db398c25), 508, 172},
1.114 + {UINT64_2PART_C(0xf6c69a72, a3989f5c), 534, 180},
1.115 + {UINT64_2PART_C(0xb7dcbf53, 54e9bece), 561, 188},
1.116 + {UINT64_2PART_C(0x88fcf317, f22241e2), 588, 196},
1.117 + {UINT64_2PART_C(0xcc20ce9b, d35c78a5), 614, 204},
1.118 + {UINT64_2PART_C(0x98165af3, 7b2153df), 641, 212},
1.119 + {UINT64_2PART_C(0xe2a0b5dc, 971f303a), 667, 220},
1.120 + {UINT64_2PART_C(0xa8d9d153, 5ce3b396), 694, 228},
1.121 + {UINT64_2PART_C(0xfb9b7cd9, a4a7443c), 720, 236},
1.122 + {UINT64_2PART_C(0xbb764c4c, a7a44410), 747, 244},
1.123 + {UINT64_2PART_C(0x8bab8eef, b6409c1a), 774, 252},
1.124 + {UINT64_2PART_C(0xd01fef10, a657842c), 800, 260},
1.125 + {UINT64_2PART_C(0x9b10a4e5, e9913129), 827, 268},
1.126 + {UINT64_2PART_C(0xe7109bfb, a19c0c9d), 853, 276},
1.127 + {UINT64_2PART_C(0xac2820d9, 623bf429), 880, 284},
1.128 + {UINT64_2PART_C(0x80444b5e, 7aa7cf85), 907, 292},
1.129 + {UINT64_2PART_C(0xbf21e440, 03acdd2d), 933, 300},
1.130 + {UINT64_2PART_C(0x8e679c2f, 5e44ff8f), 960, 308},
1.131 + {UINT64_2PART_C(0xd433179d, 9c8cb841), 986, 316},
1.132 + {UINT64_2PART_C(0x9e19db92, b4e31ba9), 1013, 324},
1.133 + {UINT64_2PART_C(0xeb96bf6e, badf77d9), 1039, 332},
1.134 + {UINT64_2PART_C(0xaf87023b, 9bf0ee6b), 1066, 340},
1.135 +};
1.136 +
1.137 +static const int kCachedPowersLength = ARRAY_SIZE(kCachedPowers);
1.138 +static const int kCachedPowersOffset = 348; // -1 * the first decimal_exponent.
1.139 +static const double kD_1_LOG2_10 = 0.30102999566398114; // 1 / lg(10)
1.140 +// Difference between the decimal exponents in the table above.
1.141 +const int PowersOfTenCache::kDecimalExponentDistance = 8;
1.142 +const int PowersOfTenCache::kMinDecimalExponent = -348;
1.143 +const int PowersOfTenCache::kMaxDecimalExponent = 340;
1.144 +
1.145 +void PowersOfTenCache::GetCachedPowerForBinaryExponentRange(
1.146 + int min_exponent,
1.147 + int max_exponent,
1.148 + DiyFp* power,
1.149 + int* decimal_exponent) {
1.150 + int kQ = DiyFp::kSignificandSize;
1.151 + double k = ceil((min_exponent + kQ - 1) * kD_1_LOG2_10);
1.152 + int foo = kCachedPowersOffset;
1.153 + int index =
1.154 + (foo + static_cast<int>(k) - 1) / kDecimalExponentDistance + 1;
1.155 + ASSERT(0 <= index && index < kCachedPowersLength);
1.156 + CachedPower cached_power = kCachedPowers[index];
1.157 + ASSERT(min_exponent <= cached_power.binary_exponent);
1.158 + ASSERT(cached_power.binary_exponent <= max_exponent);
1.159 + *decimal_exponent = cached_power.decimal_exponent;
1.160 + *power = DiyFp(cached_power.significand, cached_power.binary_exponent);
1.161 +}
1.162 +
1.163 +
1.164 +void PowersOfTenCache::GetCachedPowerForDecimalExponent(int requested_exponent,
1.165 + DiyFp* power,
1.166 + int* found_exponent) {
1.167 + ASSERT(kMinDecimalExponent <= requested_exponent);
1.168 + ASSERT(requested_exponent < kMaxDecimalExponent + kDecimalExponentDistance);
1.169 + int index =
1.170 + (requested_exponent + kCachedPowersOffset) / kDecimalExponentDistance;
1.171 + CachedPower cached_power = kCachedPowers[index];
1.172 + *power = DiyFp(cached_power.significand, cached_power.binary_exponent);
1.173 + *found_exponent = cached_power.decimal_exponent;
1.174 + ASSERT(*found_exponent <= requested_exponent);
1.175 + ASSERT(requested_exponent < *found_exponent + kDecimalExponentDistance);
1.176 +}
1.177 +
1.178 +} // namespace double_conversion
