The exponent.

The eight bits 23 through 30 contain the exponent. The exponent is an integer, but may be negative, zero, or positive. You might guess that an 8-bit two's complement integer would work perfectly for this, but a different type of notation is used.

The exponent is expressed using a **biased integer**.
The true exponent is added to `+127`

resulting in
an _{10}**unsigned** binary integer.
The biased integer is encoded using 8-bit unsigned binary.

- A biased exponent of
`+127`

represents the actual exponent 0. - A biased exponent of
`+128`

represents the actual exponent 1. - A biased exponent of
`+126`

represents the actual exponent -1.

**Exceptions:**
(1) A floating point value of `0.0`

is represented with a
mantissa of 23 zero bits and an exponent
of 8 zero bits.
It is not legal to have an exponent of zero with
a non-zero mantissa.
(2) The exponent `255`

_{10}`(1111 1111)`

is used
to signal various problems,
such as division by zero.

What is the mantissa when the entire float is zero?