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On 5/11/2010 7:41 AM, Invisible wrote:
>
> You know that there are people who do scientific experiments *about*
> computer programs, right? ;-)
>
Yeah :)
Actually, in the vein of computer science: For the fun of it I'm
designing CPU from scratch. I plan to build it with TTL gates after I
have the design complete and have vetted it through simulation. I have
the ALU designed. (Fairly simple, it can add, perform bitwise logic and
shift, as well as calculate the twos complement. Other operations will
take multiple cycles) I also have most of the control logic put
together, but I need to make some changes to ensure an ALU instruction
can occur within 2 cycles (One to latch the ALU result, one to store the
result in the accumulator)
Eventually, I want to take a simplified version of that design and
create a CPU entirely out of relays. Obviously, I'd need keep the design
as simple as possible, but still functional to keep the relay count
down. Something about a bit stack of clacking relays with blinking
lights really appeals to me. That machine will likely still have IC
memory, though, but the registers will be relay latches.
One consideration for the relay version is that the machine should be
able to halt and only resume processing on an interrupt. So, ideally,
you'd give it inputs, issue a command, and send it clacking away to get
a result.
It's fun stuff, and occupies a good deal of time. Also a great way to
learn HOW a computer like the one you're sitting at actually works. e.g.
how each instruction of machine code does what it does, etc...
The TTL version should be fun, too. I plan to have lots of LEDs to show
what's happening inside the machine.
--
~Mike
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