Using the direct addressing mode to access external symbols

External symbols, which should be accessed using the direct addressing mode, must be declared using the XREF.B directive. Symbols which are imported using XREF are accessed using the extended addressing mode.

Listing: Using direct addressing to access external symbols

     XREF.B ExternalDirLabel
     XREF   ExternalExtLabel

...

     LDA    ExternalDirLabel ; Direct addressing mode is used.

...

     LDA    ExternalExtLabel ; Extended addressing mode is used.