I've been working on the Intel iPDS driver, which is now at the stage where it is starting to boot from a floppy disk. Here is a snap:
The ROM and RAM in this system are overlapped as follows:
ROM: 0x0000 - 0x7fff
RAM: 0x0000 - 0xffff
When the O/S starts up it writes to I/O port 0xF0 to disable the ROM and make the lower half of the RAM visible. How do I acheive this with MESS? (i.e. How do I disable the address map entry for the ROM at runtime?) Is there another driver I can look at to see an example?
This is the reason for the RAM error show above.