bit numbering (Was: APL\360

Fred Cisin cisin at
Mon Feb 1 14:15:43 CST 2021

>> From: Chuck Guzis <cclist at>
>> Numbering of bits in a word is also interesting.  Is the high order bit
>> in a 64 bit word, bit 0 or bit 63?  Both conventions have been employed.
On Mon, 1 Feb 2021, John Ames via cctalk wrote:
> This one has always boggled me, because it's the one aspect of the
> Endian Wars where there's a simple, straightforward answer grounded in
> basic mathematics - base ^ digit-number only gives the correct
> place-value when the lowest-order bit is numbered zero. It's beyond my
> ken how anybody thought the reverse was *valid,* let alone a good
> idea.

It probably originated from our system of writing numbers with most 
significant on the left, least significant on the right.
Then combined with somebody not even thinking in terms of "one's 
place"/"ten's place", or "one's place"/"two's place"/"four's place" etc. 
and simply numbering from left to right.  It is unfortunate that they were 
permitted to do so.

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