コード例 #1
0
 // 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());
 }