Name
Extended Type
Syntax
type Extended;
Description
The Extended
type is an Intel standard floating-point
type that uses 10 bytes to store a sign bit, a 15-bit exponent, and a
64-bit mantissa. Extended conforms to the minimum
requirements of the IEEE-754 extended double precision type.
The limits of the Extended type are approximately
3.37 × 10-4932 to 1.18 ×
104932, with about 19 decimal digits of
precision.
Unlike Single and Double,
Extended contains all of its significant bits.
Normalized values, infinity, and not-a-number have an explicit 1 bit
as the most significant bit. Table 5-2 shows the
detailed format of finite and special Extended
values. Not all bit patterns are valid Extended
values. Delphi raises runtime error 6 (EInvalidOp)
if you try to use an invalid bit pattern as a floating-point number.
|
Numeric Class |
Sign |
Exponent Bits |
Mantissa Bits |
|
Positive | |||
|
Normalized |
0 |
0...1 to 1...0 |
10...0 to 11...1 |
|
Denormalized |
0 |
0...0 |
0...1 to 01...1 |
|
Zero |
0 |
0...0 |
0...0 |
|
Infinity |
0 |
1...1 |
10... |
|
Quiet NaN |
0 |
1...1 |
110...0 to 11...1 |
|
Signaling NaN |
0 |
1...1 |
100...1 to 101...1 |
|
Negative | |||
|
Normalized |
1 |
0...1 to 1...0 |
10...0 to 11...1 |
|
Denormalized |
1 |
0...0 |
0...1 to 01...1 |
|
Zero |
1 |
0...0 |
0...0 |
|
Infinity |
1 |
1...1 |
10... |
|
Quiet NaN |
1 |
1...1 |
110...0 to 11...1 |
|
Signaling NaN |
1 |
1...1 |
100...1 to 101...1 |
Tips and Tricks
Use
Extendedwhen you must preserve the maximum precision or exponent range, but realize that ...
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