Compatibility with HP Ada 83 (GNAT Reference Manual)

### 21.7 Compatibility with HP Ada 83 ¶

All the HP Ada 83 pragmas and attributes are recognized, although only a subset of them can sensibly be implemented. The description of pragmas in Implementation Defined Pragmas indicates whether or not they are applicable to GNAT.

- ‘Default floating-point representation’

  In GNAT, the default floating-point format is IEEE, whereas in HP Ada 83, it is VMS format.

- ‘System’

  the package System in GNAT exactly corresponds to the definition in the Ada 95 reference manual, which means that it excludes many of the HP Ada 83 extensions. However, a separate package Aux_DEC is provided that contains the additional definitions, and a special pragma, Extend_System allows this package to be treated transparently as an extension of package System.