1 Jan 2001 is etime=211845110400000000

going back 2^31      seconds = 209697626752000000 = 1932/12/13.20:45:52.000000
going back 2^31 milliseconds = 
going back 2^31 microseconds = 
going back 2^31  nanoseconds = 

going back 2^32      seconds = 207550143104000000 = 1864/11/24.17:31:44.000000

going back 2^63      seconds = -9223371825009665408000000
going back 2^63 milliseconds = -9223160191744375808000
going back 2^63 microseconds = -9011526926454775808
going back 2^63  nanoseconds = 202621738363145225 = 1708/09/22.00:12:43.145225




The time from 1 January 2001 back to these times is:

1 Jan 1980      .
1 Jan 1970      .
16 Nov 1858     .
14 Oct 1582     .
3 Jul 1037      .
18 Sep 763      .
1 Jan 1         .
24 Nov 4713 BC  .



1980/01/01      
1970/01/01      


#define XDAY_18SEP763           (0)
#define XDAY_3JUL1037           (100000)
#define XDAY_14OCT1582          (299160)
#define XDAY_16NOV1858          (400000)