logical NOT

[Mark van Dijk <lists+zsh@internecto.net>]

Before I explain what I need let me explain why I need it.

Just now I was reading about MAC addresses, their binary
representation, and how MAC addresses are transmitted across a network.
This document mentions the address AC:DE:48:00:00:00. Converting that
to binary is easy:

for i (${(s.:.):-AC:DE:48:00:00:80}) echo $(( [#2] hex=0x$i ))

Here we can see 0xAC == 2#10101100.

From what I understand this is transmitted over a network from right to
left, so the receiver will receive 00110101 in that order. In this
sequence the first transmitted bit represents the individual/group
address bit and the second one represents the universally/locally
administered address bit, the reason for me reading this.

Then I wondered about how to let zsh "reverse" a binary number and came
up with the logical NOT: simply flip each bit. I've tried a lot of ways
but they all fail. What confuses me most is this:

% echo $(( [#2] ~0xAC ))
-2#10101101

I'd appreciate thoughts on this, and to hear if it makes any sense at
all :)

Thanks,
Mark.