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1 // Copyright 2006-2008 the V8 project authors. All rights reserved. | 1 // Copyright 2006-2008 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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133 {UINT64_2PART_C(0x9e19db92, b4e31ba9), 1013, 324}, | 133 {UINT64_2PART_C(0x9e19db92, b4e31ba9), 1013, 324}, |
134 {UINT64_2PART_C(0xeb96bf6e, badf77d9), 1039, 332}, | 134 {UINT64_2PART_C(0xeb96bf6e, badf77d9), 1039, 332}, |
135 {UINT64_2PART_C(0xaf87023b, 9bf0ee6b), 1066, 340}, | 135 {UINT64_2PART_C(0xaf87023b, 9bf0ee6b), 1066, 340}, |
136 }; | 136 }; |
137 static const int kCachedPowersOffset = 348; // -kCachedPowers[0].decimal_exp
onent | 137 static const int kCachedPowersOffset = 348; // -kCachedPowers[0].decimal_exp
onent |
138 | 138 |
139 const int PowersOfTenCache::kDecimalExponentDistance = 8; // kCachedPowers[1
].decimal_exponent - kCachedPowers[0].decimal_exponent | 139 const int PowersOfTenCache::kDecimalExponentDistance = 8; // kCachedPowers[1
].decimal_exponent - kCachedPowers[0].decimal_exponent |
140 const int PowersOfTenCache::kMinDecimalExponent = -348; // kCachedPowers[0].
decimal_exponent | 140 const int PowersOfTenCache::kMinDecimalExponent = -348; // kCachedPowers[0].
decimal_exponent |
141 const int PowersOfTenCache::kMaxDecimalExponent = 340; // kCachedPowers[kCac
hedPowersLength - 1].decimal_exponent | 141 const int PowersOfTenCache::kMaxDecimalExponent = 340; // kCachedPowers[kCac
hedPowersLength - 1].decimal_exponent |
142 | 142 |
143 #ifndef NDEBUG | |
144 #if ENABLE(ASSERT) | 143 #if ENABLE(ASSERT) |
145 static const int kCachedPowersLength = ARRAY_SIZE(kCachedPowers); | 144 static const int kCachedPowersLength = ARRAY_SIZE(kCachedPowers); |
146 #endif | |
147 | 145 |
148 // Check that the static constants match the values in kCachedPowers. | 146 // Check that the static constants match the values in kCachedPowers. |
149 static void validateStaticConstants() { | 147 static void validateStaticConstants() { |
150 ASSERT(kCachedPowersOffset == -kCachedPowers[0].decimal_exponent); | 148 ASSERT(kCachedPowersOffset == -kCachedPowers[0].decimal_exponent); |
151 ASSERT(PowersOfTenCache::kDecimalExponentDistance == (kCachedPowers[1].d
ecimal_exponent - kCachedPowers[0].decimal_exponent)); | 149 ASSERT(PowersOfTenCache::kDecimalExponentDistance == (kCachedPowers[1].d
ecimal_exponent - kCachedPowers[0].decimal_exponent)); |
152 ASSERT(PowersOfTenCache::kMinDecimalExponent == kCachedPowers[0].decimal
_exponent); | 150 ASSERT(PowersOfTenCache::kMinDecimalExponent == kCachedPowers[0].decimal
_exponent); |
153 ASSERT(PowersOfTenCache::kMaxDecimalExponent == kCachedPowers[kCachedPow
ersLength - 1].decimal_exponent); | 151 ASSERT(PowersOfTenCache::kMaxDecimalExponent == kCachedPowers[kCachedPow
ersLength - 1].decimal_exponent); |
154 } | 152 } |
155 #endif | 153 #endif |
156 | 154 |
157 void PowersOfTenCache::GetCachedPowerForBinaryExponentRange( | 155 void PowersOfTenCache::GetCachedPowerForBinaryExponentRange( |
158 int min_exponent
, | 156 int min_exponent
, |
159 int max_exponent
, | 157 int max_exponent
, |
160 DiyFp* power, | 158 DiyFp* power, |
161 int* decimal_exp
onent) { | 159 int* decimal_exp
onent) { |
162 #ifndef NDEBUG | 160 #if ENABLE(ASSERT) |
163 validateStaticConstants(); | 161 validateStaticConstants(); |
164 #endif | 162 #endif |
165 int kQ = DiyFp::kSignificandSize; | 163 int kQ = DiyFp::kSignificandSize; |
166 double k = ceil((min_exponent + kQ - 1) * kD_1_LOG2_10); | 164 double k = ceil((min_exponent + kQ - 1) * kD_1_LOG2_10); |
167 int foo = kCachedPowersOffset; | 165 int foo = kCachedPowersOffset; |
168 int index = | 166 int index = |
169 (foo + static_cast<int>(k) - 1) / kDecimalExponentDistance + 1; | 167 (foo + static_cast<int>(k) - 1) / kDecimalExponentDistance + 1; |
170 ASSERT(0 <= index && index < kCachedPowersLength); | 168 ASSERT(0 <= index && index < kCachedPowersLength); |
171 CachedPower cached_power = kCachedPowers[index]; | 169 CachedPower cached_power = kCachedPowers[index]; |
172 ASSERT(min_exponent <= cached_power.binary_exponent); | 170 ASSERT(min_exponent <= cached_power.binary_exponent); |
173 ASSERT(cached_power.binary_exponent <= max_exponent); | 171 ASSERT(cached_power.binary_exponent <= max_exponent); |
174 *decimal_exponent = cached_power.decimal_exponent; | 172 *decimal_exponent = cached_power.decimal_exponent; |
175 *power = DiyFp(cached_power.significand, cached_power.binary_exponent); | 173 *power = DiyFp(cached_power.significand, cached_power.binary_exponent); |
176 } | 174 } |
177 | 175 |
178 | 176 |
179 void PowersOfTenCache::GetCachedPowerForDecimalExponent(int requested_expone
nt, | 177 void PowersOfTenCache::GetCachedPowerForDecimalExponent(int requested_expone
nt, |
180 DiyFp* power, | 178 DiyFp* power, |
181 int* found_exponent)
{ | 179 int* found_exponent)
{ |
182 ASSERT(kMinDecimalExponent <= requested_exponent); | 180 ASSERT(kMinDecimalExponent <= requested_exponent); |
183 ASSERT(requested_exponent < kMaxDecimalExponent + kDecimalExponentDistan
ce); | 181 ASSERT(requested_exponent < kMaxDecimalExponent + kDecimalExponentDistan
ce); |
184 #ifndef NDEBUG | 182 #if ENABLE(ASSERT) |
185 validateStaticConstants(); | 183 validateStaticConstants(); |
186 #endif | 184 #endif |
187 int index = | 185 int index = |
188 (requested_exponent + kCachedPowersOffset) / kDecimalExponentDistance; | 186 (requested_exponent + kCachedPowersOffset) / kDecimalExponentDistance; |
189 CachedPower cached_power = kCachedPowers[index]; | 187 CachedPower cached_power = kCachedPowers[index]; |
190 *power = DiyFp(cached_power.significand, cached_power.binary_exponent); | 188 *power = DiyFp(cached_power.significand, cached_power.binary_exponent); |
191 *found_exponent = cached_power.decimal_exponent; | 189 *found_exponent = cached_power.decimal_exponent; |
192 ASSERT(*found_exponent <= requested_exponent); | 190 ASSERT(*found_exponent <= requested_exponent); |
193 ASSERT(requested_exponent < *found_exponent + kDecimalExponentDistance); | 191 ASSERT(requested_exponent < *found_exponent + kDecimalExponentDistance); |
194 } | 192 } |
195 | 193 |
196 } // namespace double_conversion | 194 } // namespace double_conversion |
197 | 195 |
198 } // namespace WTF | 196 } // namespace WTF |
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