Sept. 6, 2002
4:01 p.m.
[Paul Svensson]
Are C doubles dense enough to offer 100 ns resolution ?
The question can't be answered unless you also specify how many years you want to cover. It takes about 25 bits to distinguish a year's worth of seconds, and an IEEE double has 53 bits to play with. So if you were only interested in representing one year, you've got about 28 bits left to play with. If you want to cover an N-year span, you've got about 28 - log2(N) bits to play with. It takes a bit over 23 bits to distinguish the number of 100 ns slices in a second, so N has to be small enough that 5 - log2(N) doesn't go negative. So if you count the start of the epoch at 1970, you've just created a year 2003 problem <wink>.