The {$CALLING } directive tells the compiler which calling convention should be used if none is specified:
{$CALLING REGISTER}
By default it is REGISTER. The following calling conventions exist:
For a more detailed explanation of calling conventions, see section 6.3, page 417. As a special case, DEFAULT can be used, to restore the default calling convention.
Remark The calling convention of a procedural type is also changed by this directive.