At 04:14 PM 6/10/03 -0700, William Chops Westfield wrote:

>I think I used a bit-reversal algorithm in a graphics hack once, but only
>because I
>wanted the leftmost bits on the printer to match the leftmost bits in the
>memory; and that was quite arbitrary; there's no reason that the MSB of a
>word has to be thought of as being "on the left."

Just like it doesn't matter how you wire up the data lines or even the low
order address lines on static ram chips (small embedded systems using 805x
or 68xx micros).  Since the same wire connections are being used to write
and read the data, the actual order doesn't matter.  Do the same to the ROM
chips and confuse the heck out of someone trying to reverse-engineer your
product.

Some people used to have a real problem with that concept.  But it sure
made it easier to lay out PCBs <grin>.

dwayne

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Dwayne Reid   <dwayner@planet.eon.net>
Trinity Electronics Systems Ltd    Edmonton, AB, CANADA
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