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Home > Floating-point Support > IEEE 754 arithmetic > Double precision data type for IEEE 754 arithmetic |

A `double`

value is 64 bits wide.

The structure is:

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`

.