Hello

Just an example. You have 32K Xdata and want that
8K are used by you C-Application, and the rest of
24K should be 'unused', which you like to use for
what ever you want.

I don't know how in SDCC the options name is,
but Keil only. My assumption is, such an option
exists in SDCC also.

Tell the compiler/linker that the system provides
only 8K Xdata, and a sucessfully compiled/linked
applthe application will not contain any Xdata
variable outside those 8K.

With the rest of 24K do what you want.

Best regards