On processors which do not support co-processor operations (and which have the {$E+} switch), the double type does not exist.

Extended

For Intel 80x86 processors, the extended type has takes up 10 bytes of memory space. For more information on the extended type consult the Intel Programmer’s reference.

For all other processors which support floating point operations, the extended type is a nickname for the type which supports the most precision, this is usually the double type. On processors which do not support co-processor operations (and which have the {$E+} switch), the extended type usually maps to the single type.

Comp

For Intel 80x86 processors, the comp type contains a 63-bit integral value, and a sign bit (in the MSB position). The comp type uses 8 bytes of storage space.

On other processors, the comp type is not supported.

Real

Contrary to Turbo Pascal, where the real type had a special internal format, under Free Pascal the real type simply maps to one of the other real types. It maps to the double type on processors which support floating point operations, while it maps to the single type on processors which do not support floating point operations in hardware. See table (8.2) for more information on this.


Table 8.2: Processor mapping of real type

Processor Real type mapping


Intel 80x86 double
Motorola 680x0 (with {$E-} switch) double
Motorola 680x0 (with {$E+} switch) single