CPE 315
Summer 2006
Professor Stearns
Lab #5 FAQ

1. Can I create two MMUs, one for each memory?
   No. You must design one MMU and instantiate it twice.
   This design is much better than trying to work with one MMU object.

2. Do we have to worry about exceptions?
   No. Assume the program generates no exception; it doesn't.

3. How big is the bus that leaves the MMU?
   These must be exactly:
   

   8 bits for the data memory.
   9 bits for the instruction memory.
   

   Note that the Ram and Rom are both word-addressable devices; they expect a word (not a byte) address.
   e.g. if you put a 4 on the address bus, it accesses MIPS address 16.
   

4. I'm confused; there are two MMUs and one page table?
   Look at the memory allocation tables at the bottom of the lab; the page frame allocations for pages 0 and 14 are identical.
   Therefore you can use the same page table; this isn't realistic but greatly simplifies the lab.

5. What happened to pages 1 and 2 in the data address space?
   Look at the code; the only data pages are 0 and 14.