0x3FEF_FFFF_FFDF_FFFF == 0.999999999767169245323827908578 (approx)
  0x3FEF_FFFF_FFE0_0000 == 0.999999999767169356346130371093 (approx)
         original value == 0.99999999976716936
  0x3FEF_FFFF_FFE0_0001 == 0.999999999767169467368432833609 (approx)