Hardware question...

[Paul Fuqua]

    Date: Tue, 23 Apr 2002 06:48:48 -0500 (CDT)
    From: Daniel Seagraves <dseagrav@sakura.lunar-tokyo.net>
    
    Are the A and M memory on two seperate boards, or are they the same thing
    on two busses?

M and A are on separate buses (on the same board, the whole CPU is on
one board).  When writing to an M-memory location, the hardware
conspires to write to the corresponding A-memory location with the same
value.  It's a cheap way to imitate a dual-ported memory:  write to M
all the time, and you can read from either M or A.  Three-operand
microinstructions take an M source and an A source.

                              pf