public static DiyFp Normalize(ref DiyFp a)
{
DiyFp result = a;
result.Normalize();
return(result);
}
// Returns the two boundaries of first argument.
// The bigger boundary (m_plus) is normalized. The lower boundary has the same
// exponent as m_plus.
internal static void NormalizedBoundaries(long d64, DiyFp mMinus, DiyFp mPlus)
{
DiyFp v = AsDiyFp(d64);
bool significandIsZero = (v.F == KHiddenBit);
mPlus.F = (v.F << 1) + 1;
mPlus.E = v.E - 1;
mPlus.Normalize();
if (significandIsZero && v.E != KDenormalExponent)
{
// The boundary is closer. Think of v = 1000e10 and v- = 9999e9.
// Then the boundary (== (v - v-)/2) is not just at a distance of 1e9 but
// at a distance of 1e8.
// The only exception is for the smallest normal: the largest denormal is
// at the same distance as its successor.
// Note: denormals have the same exponent as the smallest normals.
mMinus.F = (v.F << 2) - 1;
mMinus.E = v.E - 2;
}
else
{
mMinus.F = (v.F << 1) - 1;
mMinus.E = v.E - 1;
}
mMinus.F = mMinus.F << (mMinus.E - mPlus.E);
mMinus.E = mPlus.E;
}
// Computes the two boundaries of this.
// The bigger boundary (m_plus) is normalized. The lower boundary has the same
// exponent as m_plus.
// Precondition: the value encoded by this Single must be greater than 0.
public void NormalizedBoundaries(out DiyFp outMMinus, out DiyFp outMPlus)
{
var v = this.AsDiyFp();
var __ = new DiyFp((v.f << 1) + 1, v.e - 1);
var mPlus = DiyFp.Normalize(ref __);
var mMinus = LowerBoundaryIsCloser() ? new DiyFp((v.f << 2) - 1, v.e - 2) : new DiyFp((v.f << 1) - 1, v.e - 1);
mMinus.f <<= mMinus.e - mPlus.e;
mMinus.e = mPlus.e;
outMPlus = mPlus;
outMMinus = mMinus;
}
private static unsafe int Grisu2(double value, char *buffer, out int K)
{
var v = new DiyFp(value);
v.NormalizedBoundaries(out var w_m, out var w_p);
var c_mk = GetCachedPower(w_p.e, out K);
var W = v.Normalize() * c_mk;
var Wp = w_p * c_mk;
var Wm = w_m * c_mk;
Wm.f++;
Wp.f--;
return(DigitGen(W, Wp, Wp.f - Wm.f, buffer, ref K));
}
private static unsafe int Grisu2(double value, char *buffer, out int K)
{
DiyFp diyFp = new DiyFp(value);
DiyFp minus;
DiyFp plus;
diyFp.NormalizedBoundaries(out minus, out plus);
DiyFp cachedPower = GetCachedPower(plus.e, out K);
DiyFp w = diyFp.Normalize() * cachedPower;
DiyFp mp = plus * cachedPower;
DiyFp diyFp2 = minus * cachedPower;
diyFp2.f++;
mp.f--;
return(DigitGen(w, mp, mp.f - diyFp2.f, buffer, ref K));
}
