Sign Bit Field - ashtech GG Surveyor Reference Manual

The GG Surveyor stores the floating point data types using the IEEE single and double
precision format. The formats contain a sign bit field, an exponent field, and a fraction
field. The value is represented in these three fields.

Sign Bit Field

The sign bit field of the number being represented is stored in the sign bit field. If the
number is positive, the sign bit field contains the value 0. If the number is negative, the
sign bit field contains the value 1. The sign bit field is stored in the most significant bit of
a floating point value.
Exponent Field
The exponent of a number is multiplied by the fractional value of the number to get a
value. The exponent field of the number contains a biased form of the exponent. The bias
is subtracted from the exponent field to get the actual exponent. This allows both positive
and negative exponents.
Fraction Field
The IEEE floating point format stores the fractional part of a number in a normalized
form. This form assumes that all non-zero numbers are of the form:
1.xxxxxx (binary)
The character 'x' represents either a 0 or 1 (binary).
Because all floating point binary numbers begin with 1, the 1 becomes the implicit
normalized bit and is omitted. It is the most significant bit of the fraction, and the binary
point is located immediately to its right. All bits after the binary point represent values
less than 1 (binary). For example, the number 1.625 (decimal) can be represented as:
1.101 (binary) which is equal to:
2^0 + 2^-1 + 2^-3 (decimal) which is equal to:
1 + 0.5 + 0.125 (decimal) which is equal to:
1.625 (decimal).
Floating Point Data Representation D-1