Ben Murdoch | 3fb3ca8 | 2011-12-02 17:19:32 +0000 | [diff] [blame] | 1 | // Copyright 2011 the V8 project authors. All rights reserved. |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
Ben Murdoch | f87a203 | 2010-10-22 12:50:53 +0100 | [diff] [blame] | 4 | |
Ben Murdoch | f87a203 | 2010-10-22 12:50:53 +0100 | [diff] [blame] | 5 | #include <limits.h> |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 6 | #include <stdarg.h> |
| 7 | #include <cmath> |
Ben Murdoch | f87a203 | 2010-10-22 12:50:53 +0100 | [diff] [blame] | 8 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 9 | #include "include/v8stdint.h" |
| 10 | #include "src/base/logging.h" |
| 11 | #include "src/cached-powers.h" |
| 12 | #include "src/globals.h" |
Ben Murdoch | f87a203 | 2010-10-22 12:50:53 +0100 | [diff] [blame] | 13 | |
| 14 | namespace v8 { |
| 15 | namespace internal { |
| 16 | |
| 17 | struct CachedPower { |
| 18 | uint64_t significand; |
| 19 | int16_t binary_exponent; |
| 20 | int16_t decimal_exponent; |
| 21 | }; |
| 22 | |
| 23 | static const CachedPower kCachedPowers[] = { |
John Reck | 5913587 | 2010-11-02 12:39:01 -0700 | [diff] [blame] | 24 | {V8_2PART_UINT64_C(0xfa8fd5a0, 081c0288), -1220, -348}, |
| 25 | {V8_2PART_UINT64_C(0xbaaee17f, a23ebf76), -1193, -340}, |
| 26 | {V8_2PART_UINT64_C(0x8b16fb20, 3055ac76), -1166, -332}, |
| 27 | {V8_2PART_UINT64_C(0xcf42894a, 5dce35ea), -1140, -324}, |
| 28 | {V8_2PART_UINT64_C(0x9a6bb0aa, 55653b2d), -1113, -316}, |
Ben Murdoch | f87a203 | 2010-10-22 12:50:53 +0100 | [diff] [blame] | 29 | {V8_2PART_UINT64_C(0xe61acf03, 3d1a45df), -1087, -308}, |
| 30 | {V8_2PART_UINT64_C(0xab70fe17, c79ac6ca), -1060, -300}, |
| 31 | {V8_2PART_UINT64_C(0xff77b1fc, bebcdc4f), -1034, -292}, |
| 32 | {V8_2PART_UINT64_C(0xbe5691ef, 416bd60c), -1007, -284}, |
| 33 | {V8_2PART_UINT64_C(0x8dd01fad, 907ffc3c), -980, -276}, |
| 34 | {V8_2PART_UINT64_C(0xd3515c28, 31559a83), -954, -268}, |
| 35 | {V8_2PART_UINT64_C(0x9d71ac8f, ada6c9b5), -927, -260}, |
| 36 | {V8_2PART_UINT64_C(0xea9c2277, 23ee8bcb), -901, -252}, |
| 37 | {V8_2PART_UINT64_C(0xaecc4991, 4078536d), -874, -244}, |
| 38 | {V8_2PART_UINT64_C(0x823c1279, 5db6ce57), -847, -236}, |
| 39 | {V8_2PART_UINT64_C(0xc2109436, 4dfb5637), -821, -228}, |
| 40 | {V8_2PART_UINT64_C(0x9096ea6f, 3848984f), -794, -220}, |
| 41 | {V8_2PART_UINT64_C(0xd77485cb, 25823ac7), -768, -212}, |
| 42 | {V8_2PART_UINT64_C(0xa086cfcd, 97bf97f4), -741, -204}, |
| 43 | {V8_2PART_UINT64_C(0xef340a98, 172aace5), -715, -196}, |
| 44 | {V8_2PART_UINT64_C(0xb23867fb, 2a35b28e), -688, -188}, |
| 45 | {V8_2PART_UINT64_C(0x84c8d4df, d2c63f3b), -661, -180}, |
| 46 | {V8_2PART_UINT64_C(0xc5dd4427, 1ad3cdba), -635, -172}, |
| 47 | {V8_2PART_UINT64_C(0x936b9fce, bb25c996), -608, -164}, |
| 48 | {V8_2PART_UINT64_C(0xdbac6c24, 7d62a584), -582, -156}, |
| 49 | {V8_2PART_UINT64_C(0xa3ab6658, 0d5fdaf6), -555, -148}, |
| 50 | {V8_2PART_UINT64_C(0xf3e2f893, dec3f126), -529, -140}, |
| 51 | {V8_2PART_UINT64_C(0xb5b5ada8, aaff80b8), -502, -132}, |
| 52 | {V8_2PART_UINT64_C(0x87625f05, 6c7c4a8b), -475, -124}, |
| 53 | {V8_2PART_UINT64_C(0xc9bcff60, 34c13053), -449, -116}, |
| 54 | {V8_2PART_UINT64_C(0x964e858c, 91ba2655), -422, -108}, |
| 55 | {V8_2PART_UINT64_C(0xdff97724, 70297ebd), -396, -100}, |
| 56 | {V8_2PART_UINT64_C(0xa6dfbd9f, b8e5b88f), -369, -92}, |
| 57 | {V8_2PART_UINT64_C(0xf8a95fcf, 88747d94), -343, -84}, |
| 58 | {V8_2PART_UINT64_C(0xb9447093, 8fa89bcf), -316, -76}, |
| 59 | {V8_2PART_UINT64_C(0x8a08f0f8, bf0f156b), -289, -68}, |
| 60 | {V8_2PART_UINT64_C(0xcdb02555, 653131b6), -263, -60}, |
| 61 | {V8_2PART_UINT64_C(0x993fe2c6, d07b7fac), -236, -52}, |
| 62 | {V8_2PART_UINT64_C(0xe45c10c4, 2a2b3b06), -210, -44}, |
| 63 | {V8_2PART_UINT64_C(0xaa242499, 697392d3), -183, -36}, |
| 64 | {V8_2PART_UINT64_C(0xfd87b5f2, 8300ca0e), -157, -28}, |
| 65 | {V8_2PART_UINT64_C(0xbce50864, 92111aeb), -130, -20}, |
| 66 | {V8_2PART_UINT64_C(0x8cbccc09, 6f5088cc), -103, -12}, |
| 67 | {V8_2PART_UINT64_C(0xd1b71758, e219652c), -77, -4}, |
| 68 | {V8_2PART_UINT64_C(0x9c400000, 00000000), -50, 4}, |
| 69 | {V8_2PART_UINT64_C(0xe8d4a510, 00000000), -24, 12}, |
| 70 | {V8_2PART_UINT64_C(0xad78ebc5, ac620000), 3, 20}, |
| 71 | {V8_2PART_UINT64_C(0x813f3978, f8940984), 30, 28}, |
| 72 | {V8_2PART_UINT64_C(0xc097ce7b, c90715b3), 56, 36}, |
| 73 | {V8_2PART_UINT64_C(0x8f7e32ce, 7bea5c70), 83, 44}, |
| 74 | {V8_2PART_UINT64_C(0xd5d238a4, abe98068), 109, 52}, |
| 75 | {V8_2PART_UINT64_C(0x9f4f2726, 179a2245), 136, 60}, |
| 76 | {V8_2PART_UINT64_C(0xed63a231, d4c4fb27), 162, 68}, |
| 77 | {V8_2PART_UINT64_C(0xb0de6538, 8cc8ada8), 189, 76}, |
| 78 | {V8_2PART_UINT64_C(0x83c7088e, 1aab65db), 216, 84}, |
| 79 | {V8_2PART_UINT64_C(0xc45d1df9, 42711d9a), 242, 92}, |
| 80 | {V8_2PART_UINT64_C(0x924d692c, a61be758), 269, 100}, |
| 81 | {V8_2PART_UINT64_C(0xda01ee64, 1a708dea), 295, 108}, |
| 82 | {V8_2PART_UINT64_C(0xa26da399, 9aef774a), 322, 116}, |
| 83 | {V8_2PART_UINT64_C(0xf209787b, b47d6b85), 348, 124}, |
| 84 | {V8_2PART_UINT64_C(0xb454e4a1, 79dd1877), 375, 132}, |
| 85 | {V8_2PART_UINT64_C(0x865b8692, 5b9bc5c2), 402, 140}, |
| 86 | {V8_2PART_UINT64_C(0xc83553c5, c8965d3d), 428, 148}, |
| 87 | {V8_2PART_UINT64_C(0x952ab45c, fa97a0b3), 455, 156}, |
| 88 | {V8_2PART_UINT64_C(0xde469fbd, 99a05fe3), 481, 164}, |
| 89 | {V8_2PART_UINT64_C(0xa59bc234, db398c25), 508, 172}, |
| 90 | {V8_2PART_UINT64_C(0xf6c69a72, a3989f5c), 534, 180}, |
| 91 | {V8_2PART_UINT64_C(0xb7dcbf53, 54e9bece), 561, 188}, |
| 92 | {V8_2PART_UINT64_C(0x88fcf317, f22241e2), 588, 196}, |
| 93 | {V8_2PART_UINT64_C(0xcc20ce9b, d35c78a5), 614, 204}, |
| 94 | {V8_2PART_UINT64_C(0x98165af3, 7b2153df), 641, 212}, |
| 95 | {V8_2PART_UINT64_C(0xe2a0b5dc, 971f303a), 667, 220}, |
| 96 | {V8_2PART_UINT64_C(0xa8d9d153, 5ce3b396), 694, 228}, |
| 97 | {V8_2PART_UINT64_C(0xfb9b7cd9, a4a7443c), 720, 236}, |
| 98 | {V8_2PART_UINT64_C(0xbb764c4c, a7a44410), 747, 244}, |
| 99 | {V8_2PART_UINT64_C(0x8bab8eef, b6409c1a), 774, 252}, |
| 100 | {V8_2PART_UINT64_C(0xd01fef10, a657842c), 800, 260}, |
| 101 | {V8_2PART_UINT64_C(0x9b10a4e5, e9913129), 827, 268}, |
| 102 | {V8_2PART_UINT64_C(0xe7109bfb, a19c0c9d), 853, 276}, |
| 103 | {V8_2PART_UINT64_C(0xac2820d9, 623bf429), 880, 284}, |
| 104 | {V8_2PART_UINT64_C(0x80444b5e, 7aa7cf85), 907, 292}, |
| 105 | {V8_2PART_UINT64_C(0xbf21e440, 03acdd2d), 933, 300}, |
| 106 | {V8_2PART_UINT64_C(0x8e679c2f, 5e44ff8f), 960, 308}, |
| 107 | {V8_2PART_UINT64_C(0xd433179d, 9c8cb841), 986, 316}, |
| 108 | {V8_2PART_UINT64_C(0x9e19db92, b4e31ba9), 1013, 324}, |
| 109 | {V8_2PART_UINT64_C(0xeb96bf6e, badf77d9), 1039, 332}, |
| 110 | {V8_2PART_UINT64_C(0xaf87023b, 9bf0ee6b), 1066, 340}, |
| 111 | }; |
| 112 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 113 | #ifdef DEBUG |
| 114 | static const int kCachedPowersLength = arraysize(kCachedPowers); |
| 115 | #endif |
| 116 | |
Ben Murdoch | 3ef787d | 2012-04-12 10:51:47 +0100 | [diff] [blame] | 117 | static const int kCachedPowersOffset = 348; // -1 * the first decimal_exponent. |
Ben Murdoch | f87a203 | 2010-10-22 12:50:53 +0100 | [diff] [blame] | 118 | static const double kD_1_LOG2_10 = 0.30102999566398114; // 1 / lg(10) |
Ben Murdoch | 3ef787d | 2012-04-12 10:51:47 +0100 | [diff] [blame] | 119 | // Difference between the decimal exponents in the table above. |
| 120 | const int PowersOfTenCache::kDecimalExponentDistance = 8; |
| 121 | const int PowersOfTenCache::kMinDecimalExponent = -348; |
| 122 | const int PowersOfTenCache::kMaxDecimalExponent = 340; |
Ben Murdoch | f87a203 | 2010-10-22 12:50:53 +0100 | [diff] [blame] | 123 | |
John Reck | 5913587 | 2010-11-02 12:39:01 -0700 | [diff] [blame] | 124 | void PowersOfTenCache::GetCachedPowerForBinaryExponentRange( |
| 125 | int min_exponent, |
| 126 | int max_exponent, |
| 127 | DiyFp* power, |
| 128 | int* decimal_exponent) { |
| 129 | int kQ = DiyFp::kSignificandSize; |
Ben Murdoch | 3fb3ca8 | 2011-12-02 17:19:32 +0000 | [diff] [blame] | 130 | // Some platforms return incorrect sign on 0 result. We can ignore that here, |
| 131 | // which means we can avoid depending on platform.h. |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 132 | double k = std::ceil((min_exponent + kQ - 1) * kD_1_LOG2_10); |
John Reck | 5913587 | 2010-11-02 12:39:01 -0700 | [diff] [blame] | 133 | int foo = kCachedPowersOffset; |
| 134 | int index = |
| 135 | (foo + static_cast<int>(k) - 1) / kDecimalExponentDistance + 1; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 136 | DCHECK(0 <= index && index < kCachedPowersLength); |
John Reck | 5913587 | 2010-11-02 12:39:01 -0700 | [diff] [blame] | 137 | CachedPower cached_power = kCachedPowers[index]; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 138 | DCHECK(min_exponent <= cached_power.binary_exponent); |
| 139 | DCHECK(cached_power.binary_exponent <= max_exponent); |
John Reck | 5913587 | 2010-11-02 12:39:01 -0700 | [diff] [blame] | 140 | *decimal_exponent = cached_power.decimal_exponent; |
| 141 | *power = DiyFp(cached_power.significand, cached_power.binary_exponent); |
| 142 | } |
| 143 | |
| 144 | |
| 145 | void PowersOfTenCache::GetCachedPowerForDecimalExponent(int requested_exponent, |
| 146 | DiyFp* power, |
| 147 | int* found_exponent) { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 148 | DCHECK(kMinDecimalExponent <= requested_exponent); |
| 149 | DCHECK(requested_exponent < kMaxDecimalExponent + kDecimalExponentDistance); |
John Reck | 5913587 | 2010-11-02 12:39:01 -0700 | [diff] [blame] | 150 | int index = |
| 151 | (requested_exponent + kCachedPowersOffset) / kDecimalExponentDistance; |
| 152 | CachedPower cached_power = kCachedPowers[index]; |
| 153 | *power = DiyFp(cached_power.significand, cached_power.binary_exponent); |
| 154 | *found_exponent = cached_power.decimal_exponent; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 155 | DCHECK(*found_exponent <= requested_exponent); |
| 156 | DCHECK(requested_exponent < *found_exponent + kDecimalExponentDistance); |
Ben Murdoch | f87a203 | 2010-10-22 12:50:53 +0100 | [diff] [blame] | 157 | } |
| 158 | |
| 159 | } } // namespace v8::internal |