Free Pascal uses the math coprocessor (or emulation) for all its floating-point
calculations. The Real native type is processor dependant, but it is either Single or
Double. Only the IEEE floating point types are supported, and these depend on the target
processor and emulation options. The true Turbo Pascal compatible types are listed in table
(3.4).
Table 3.4:
Supported Real types
Type
Range
Significant digits
Size
Real
platform dependant
???
4 or 8
Single
1.5E-45 .. 3.4E38
7-8
4
Double
5.0E-324 .. 1.7E308
15-16
8
Extended
1.9E-4951 .. 1.1E4932
19-20
10
Comp
-2E64+1 .. 2E63-1
19-20
8
The Comp type is, in effect, a 64-bit integer and is not available on all target platforms. To get
more information on the supported types for each platform, refer to the Programmers
guide.