4.3.4.8 How Can I Pack Data Into Flash Memory?

When using dsPIC33C/E/F and dsPIC30F devices, you can specify the upper byte of variables stored into space(prog) sections using either the -mfillupper option or the fillupper variable attribute. See the following sections of this user’s guide for more information:

Options Specific to DSC Devices (-mfillupper)

Variable Attributes (fillupper)