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clipka wrote:
> Even then, you'd have some log8(N) dependency of gate levels needed,
> where N isn't even the amount of memory, but the number of address lines.
I'm not really following...
> 1 level: 8 address lines - up to 256 words (*)
> 2 levels: 64 address lines - up to 16 Exawords
Except ... you need that fan-in for each word you address. Now you have a
problem of fan-out, as well, if I'm visualizing what you're saying correctly.
In theory, any logic function (including an entire CPU) can be built from
two levels of gates. In practice, the fan-in and fan-out kills you, because
you can't have 256 fan-outs going into each of 256 additional gates.
--
Darren New, San Diego CA, USA (PST)
Eiffel - The language that lets you specify exactly
that the code does what you think it does, even if
it doesn't do what you wanted.
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