Sun Aug 3 17:01:46 EDT 2014

One poles

Problem is this needs a new routine.
Design it for:
- signed operation (increment can be negative)
- arbitrary poles in [0,1]

Probably best to use the existing 16x16 multiplication and taylor it
for fixed point.

Having a hard time not to prematurely optimize this..

Feeling a little thick headed as well.

Anyways, going for the signed stuff.  Trouble is that picking the high
word allows only values in [-0.5,+0.5]

So let's pick a different multiply: signed x unsigned -> signed.

See _*>>16 in dtc.f

Still using this to do any DSP is an excercise in moving bytes
around..  How to make that better?