// Returns a - b.
// The exponents of both numbers must be the same and this must be bigger
// than other. The result will not be normalized.
static DiyFp minus(DiyFp a, DiyFp b) {
DiyFp result = new DiyFp(a.f, a.e);
result.subtract(b);
return result;
}
// returns a * b;
static DiyFp times(DiyFp a, DiyFp b) {
DiyFp result = new DiyFp(a.f, a.e);
result.multiply(b);
return result;
}
static DiyFp normalize(DiyFp a) {
DiyFp result = new DiyFp(a.f, a.e);
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.
static void normalizedBoundaries(long d64, DiyFp m_minus, DiyFp m_plus) {
DiyFp v = asDiyFp(d64);
boolean significand_is_zero = (v.f() == kHiddenBit);
m_plus.setF((v.f() << 1) + 1);
m_plus.setE(v.e() - 1);
m_plus.normalize();
if (significand_is_zero && 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.
m_minus.setF((v.f() << 2) - 1);
m_minus.setE(v.e() - 2);
} else {
m_minus.setF((v.f() << 1) - 1);
m_minus.setE(v.e() - 1);
}
m_minus.setF(m_minus.f() << (m_minus.e() - m_plus.e()));
m_minus.setE(m_plus.e());
}
