/* ====================================================================
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Licensed to the Apache Software Foundation (ASF) under one or more
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contributor license agreements. See the NOTICE file distributed with
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this work for Additional information regarding copyright ownership.
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The ASF licenses this file to You under the Apache License, Version 2.0
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(the "License"); you may not use this file except in compliance with
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the License. You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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==================================================================== */
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namespace HH.WMS.Utils.NPOI.SS.Util
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{
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using System;
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using HH.WMS.Utils.NPOI.Util;
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public class MutableFPNumber
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{
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// TODO - what about values between (10<sup>14</sup>-0.5) and (10<sup>14</sup>-0.05) ?
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/**
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* The minimum value in 'Base-10 normalised form'.<br/>
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* When {@link #_binaryExponent} == 46 this is the the minimum {@link #_frac} value
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* (10<sup>14</sup>-0.05) * 2^17
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* <br/>
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* Values between (10<sup>14</sup>-0.05) and 10<sup>14</sup> will be represented as '1'
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* followed by 14 zeros.
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* Values less than (10<sup>14</sup>-0.05) will get Shifted by one more power of 10
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*
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* This frac value rounds to '1' followed by fourteen zeros with an incremented decimal exponent
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*/
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//private static BigInteger BI_MIN_BASE = new BigInteger("0B5E620F47FFFE666", 16);
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private static BigInteger BI_MIN_BASE = new BigInteger(new int[] { -1243209484, 2147477094 }, 1);
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/**
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* For 'Base-10 normalised form'<br/>
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* The maximum {@link #_frac} value when {@link #_binaryExponent} == 49
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* (10^15-0.5) * 2^14
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*/
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//private static BigInteger BI_MAX_BASE = new BigInteger("0E35FA9319FFFE000", 16);
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private static BigInteger BI_MAX_BASE = new BigInteger(new int[] { -480270031, -1610620928 }, 1);
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/**
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* Width of a long
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*/
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private static int C_64 = 64;
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/**
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* Minimum precision after discarding whole 32-bit words from the significand
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*/
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private static int MIN_PRECISION = 72;
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private BigInteger _significand;
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private int _binaryExponent;
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public MutableFPNumber(BigInteger frac, int binaryExponent)
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{
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_significand = frac;
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_binaryExponent = binaryExponent;
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}
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public MutableFPNumber Copy()
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{
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return new MutableFPNumber(_significand, _binaryExponent);
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}
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public void Normalise64bit()
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{
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int oldBitLen = _significand.BitLength();
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int sc = oldBitLen - C_64;
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if (sc == 0)
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{
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return;
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}
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if (sc < 0)
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{
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throw new InvalidOperationException("Not enough precision");
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}
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_binaryExponent += sc;
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if (sc > 32)
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{
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int highShift = (sc - 1) & 0xFFFFE0;
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_significand = _significand>>(highShift);
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sc -= highShift;
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oldBitLen -= highShift;
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}
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if (sc < 1)
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{
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throw new InvalidOperationException();
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}
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_significand = Rounder.Round(_significand, sc);
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if (_significand.BitLength() > oldBitLen)
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{
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sc++;
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_binaryExponent++;
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}
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_significand = _significand>>(sc);
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}
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public int Get64BitNormalisedExponent()
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{
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//return _binaryExponent + _significand.BitCount() - C_64;
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return _binaryExponent + _significand.BitLength() - C_64;
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}
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public bool IsBelowMaxRep()
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{
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int sc = _significand.BitLength() - C_64;
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//return _significand<(BI_MAX_BASE<<(sc));
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return _significand.CompareTo(BI_MAX_BASE.ShiftLeft(sc)) < 0;
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}
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public bool IsAboveMinRep()
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{
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int sc = _significand.BitLength() - C_64;
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return _significand.CompareTo(BI_MIN_BASE.ShiftLeft(sc)) > 0;
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//return _significand>(BI_MIN_BASE<<(sc));
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}
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public NormalisedDecimal CreateNormalisedDecimal(int pow10)
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{
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// missingUnderBits is (0..3)
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int missingUnderBits = _binaryExponent - 39;
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int fracPart = (_significand.IntValue() << missingUnderBits) & 0xFFFF80;
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long wholePart = (_significand>>(C_64 - _binaryExponent - 1)).LongValue();
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return new NormalisedDecimal(wholePart, fracPart, pow10);
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}
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public void multiplyByPowerOfTen(int pow10)
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{
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TenPower tp = TenPower.GetInstance(Math.Abs(pow10));
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if (pow10 < 0)
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{
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mulShift(tp._divisor, tp._divisorShift);
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}
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else
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{
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mulShift(tp._multiplicand, tp._multiplierShift);
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}
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}
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private void mulShift(BigInteger multiplicand, int multiplierShift)
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{
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_significand = _significand*multiplicand;
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_binaryExponent += multiplierShift;
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// check for too much precision
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int sc = (_significand.BitLength() - MIN_PRECISION) & unchecked((int)0xFFFFFFE0);
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// mask Makes multiples of 32 which optimises BigInt32.ShiftRight
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if (sc > 0)
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{
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// no need to round because we have at least 8 bits of extra precision
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_significand = _significand>>(sc);
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_binaryExponent += sc;
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}
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}
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private class Rounder
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{
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private static BigInteger[] HALF_BITS;
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static Rounder()
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{
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BigInteger[] bis = new BigInteger[33];
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long acc = 1;
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for (int i = 1; i < bis.Length; i++)
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{
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bis[i] = new BigInteger(acc);
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acc <<= 1;
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}
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HALF_BITS = bis;
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}
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/**
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* @param nBits number of bits to shift right
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*/
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public static BigInteger Round(BigInteger bi, int nBits)
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{
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if (nBits < 1)
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{
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return bi;
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}
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return bi+(HALF_BITS[nBits]);
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}
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}
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/**
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* Holds values for quick multiplication and division by 10
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*/
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private class TenPower
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{
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private static BigInteger FIVE = new BigInteger(5L);// new BigInteger("5",10);
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private static TenPower[] _cache = new TenPower[350];
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public BigInteger _multiplicand;
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public BigInteger _divisor;
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public int _divisorShift;
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public int _multiplierShift;
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private TenPower(int index)
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{
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//BigInteger fivePowIndex = FIVE.ModPow(new BigInteger(index),FIVE);
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BigInteger fivePowIndex = FIVE.Pow(index);
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int bitsDueToFiveFactors = fivePowIndex.BitLength();
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int px = 80 + bitsDueToFiveFactors;
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BigInteger fx = (BigInteger.ONE << px) / (fivePowIndex);
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int adj = fx.BitLength() - 80;
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_divisor = fx>>(adj);
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bitsDueToFiveFactors -= adj;
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_divisorShift = -(bitsDueToFiveFactors + index + 80);
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int sc = fivePowIndex.BitLength() - 68;
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if (sc > 0)
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{
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_multiplierShift = index + sc;
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_multiplicand = fivePowIndex>>(sc);
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}
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else
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{
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_multiplierShift = index;
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_multiplicand = fivePowIndex;
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}
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}
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public static TenPower GetInstance(int index)
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{
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TenPower result = _cache[index];
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if (result == null)
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{
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result = new TenPower(index);
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_cache[index] = result;
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}
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return result;
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}
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}
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public ExpandedDouble CreateExpandedDouble()
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{
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return new ExpandedDouble(_significand, _binaryExponent);
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}
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}
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}
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