Assigning 'nochage' to a variable.

[Terry Hancock]

On Sunday 04 September 2005 06:34 pm, Terry Reedy wrote:
> > resembling the 'Z'-state of a electronic tri-state output?
> 
> Not familiar with that.

"Tri-state" logic gate outputs can do one of three things:

 1) They can drive the voltage to 0.0  "0"
 2) They can drive the voltage to VCC  "1"
 3) They can act like they aren't connected at all "Z"

The "Z" actually is the standard symbol for "impedence" (in
DC circuits this is just a fancy way to say "resistance"), and
is short for "high-Z state" or "high impedence state", which
is very much like what would happen if you just cut the wire.

Sending gates into the Z state is what allows computer buses
to work at all -- only the addressed register is allowed to
control the bus wires, all other connected devices are in the
Z state.

The software equivalent is throwing certain terms out of
a sum.  We usually do that with control flow.  Doing it
implicitly by value seems like it could be dangerous, but
I'd have to see a more complete implementation example to
be convinced one way or the other about that.

Cheers,
Terry

--
Terry Hancock ( hancock at anansispaceworks.com )
Anansi Spaceworks  http://www.anansispaceworks.com