The {$INLINE ON} directive tells the compiler that the Inline procedure modifier should be allowed. Procedures that are declared inline are copied to the places where they are called. This has the effect that there is no actual procedure call, the code of the procedure is just copied to where the procedure is needed, this results in faster execution speed if the function or procedure is used a lot.
By default, Inline procedures are not allowed. This directive must be specified to use inlined code. The directive is equivalent to the command line switch -Si. For more information on inline routines, consult the Reference Guide.