コード例 #1
0
ファイル: Number.Grisu3.cs プロジェクト: mikem8361/runtime
            public static bool TryRunHalf(Half value, int requestedDigits, ref NumberBuffer number)
            {
                Half v = Half.IsNegative(value) ? Half.Negate(value) : value;

                Debug.Assert((double)v > 0);
                Debug.Assert(Half.IsFinite(v));

                int  length;
                int  decimalExponent;
                bool result;

                if (requestedDigits == -1)
                {
                    DiyFp w = DiyFp.CreateAndGetBoundaries(v, out DiyFp boundaryMinus, out DiyFp boundaryPlus).Normalize();
                    result = TryRunShortest(in boundaryMinus, in w, in boundaryPlus, number.Digits, out length, out decimalExponent);
                }
                else
                {
                    DiyFp w = new DiyFp(v).Normalize();
                    result = TryRunCounted(in w, requestedDigits, number.Digits, out length, out decimalExponent);
                }

                if (result)
                {
                    Debug.Assert((requestedDigits == -1) || (length == requestedDigits));

                    number.Scale          = length + decimalExponent;
                    number.Digits[length] = (byte)('\0');
                    number.DigitsCount    = length;
                }

                return(result);
            }
コード例 #2
0
        public static unsafe void Dragon4Half(Half value, int cutoffNumber, bool isSignificantDigits, ref NumberBuffer number)
        {
            Half v = Half.IsNegative(value) ? Half.Negate(value) : value;

            Debug.Assert((double)v > 0.0);
            Debug.Assert(Half.IsFinite(v));

            ushort mantissa = ExtractFractionAndBiasedExponent(value, out int exponent);

            uint mantissaHighBitIdx;
            bool hasUnequalMargins = false;

            if ((mantissa >> DiyFp.HalfImplicitBitIndex) != 0)
            {
                mantissaHighBitIdx = DiyFp.HalfImplicitBitIndex;
                hasUnequalMargins  = (mantissa == (1U << DiyFp.HalfImplicitBitIndex));
            }
            else
            {
                Debug.Assert(mantissa != 0);
                mantissaHighBitIdx = (uint)BitOperations.Log2(mantissa);
            }

            int length = (int)(Dragon4(mantissa, exponent, mantissaHighBitIdx, hasUnequalMargins, cutoffNumber, isSignificantDigits, number.Digits, out int decimalExponent));

            number.Scale          = decimalExponent + 1;
            number.Digits[length] = (byte)('\0');
            number.DigitsCount    = length;
        }