zdump -v factor-of-2 speedup on 64-bit hosts (-500 -> 1800)

[Clive D.W. Feather]

Paul Eggert said:
> For example, it would get hopelessly
> confused (loop or crash or report wrong data, I don't know what) if
> given an implementation that accurately implemented the calendar used
> in the English colonies in America before 1750, where the year began
> on March 25.

Nitpick - the last year starting on March 25th in England was 1751 (which
was therefore only 287 days long, much less than the 355 days of 1752).

> One other data point: in all
> of these other systems, leap years are not even a multiple of 4,

Right: the leap day previous to 1752-02-29 was 1747-02-29, 24 days before
the end of 1747.

-- 
Clive D.W. Feather  | Work:  <clive at demon.net>   | Tel:    +44 20 8495 6138
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Thus plc            |                            |