3.6.3 Double precision data type for IEEE 754 arithmetic

A double value is 64 bits wide.

The structure is:

Figure 3-2 IEEE 754 double-precision floating-point format
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As with single-precision float data types, S is the sign, Exp the exponent, and Frac the fraction. Most of the detail of float values remains true for double values, except that:

  • The Exp field is biased by 0x3FF (1023) instead of 0x7F, so numbers between 1.0 and 2.0 have an Exp field of 0x3FF.

  • The Exp value representing infinity and NaNs is 0x7FF (2047) instead of 0xFF.

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