Changes
/* Technical */
Part of the Brunword word processor is copied into RAM. This is done by it's "extension rom".
The ROM Select port (&DFXX) is decoded and has 2 roles. (It is decoded in the standard way, with bit 13 of the port address must be set to 0).
First is to select which ROM page appears in the range &C000-&FFFF of the Z80's address space.
