IA32浮点数的3种存储格式

    The following table sums up the three types of floating-point formats used on the standard IA-32 platform.

Data Type           Length    Significand    Bits Exponent         Bits Range
Single precision      32         24             8             1.18 x 10^-38 to 3.40 x 10^38
Double precision      64         53             11            2.23 x 10^-308 to 1.79 x 10^308
Double extended       80         64             15            3.37 x 10^-4932 to 1.18 x 10^4932