More thoughts on building a Z-80 (64bit!!!)

At 09:45 AM 10/22/98 -0500, it was written: ... ... Well, if you want to dream, and you have a _LOT_ of very fast memory available, you can build a 2Ghz Z80 as follows: Build the system with two sets of memory, one bank contains combinations of bank number and address, the other contains several million 64K memory images. Now "compile" your code by creating a directed graph of all possible memory states for all possible execution paths (detection when the graph collapses into loops of course) and load your memory. Now you can "execute" your code by reading the control bank and switching to the bank indicated and reading again. Each "execution" would cost 1 memory fetch. With predictive execution (that is to say when you know that you are going to move the next four states in sequence) you can "jump ahead" to the fourth state thus effectively execution 4 instructions in one memory fetch time. Clearly the slowest mode of execution will be all register manipulation/conditional jump instructions (no predictions are used immediately) The fastest execution will be execution that doesn't generate I/O (external non-memory based state) then you can go right to the end state. --Chuck