|<-- integer part ->| |<- fraction part ->|
+----+----+----+ +----+----+----+----+ +----+----+
| | 1! | 2! | .. | i! | | 1! | 2! | .. | f! | |
+----+----+----+ +----+----+----+----+ +----+----+
0 1 2 i G G+1 G+2 G+f G2
[0] The sign.
[1] An integer portion of i factorial-base digits.
| The value of [n] ranges from 0 to n, The value
[i] of the integer portion is ?*1! + ?*2! + ... + ?*i!
[G] A guard to detect integer overflow.
[G+1] Records carrys & borrows during normalization.
[G+2] A fractional portion of f-1 factorial-base digits.
| The value of [n] ranges from 0 to n-1. The value
[G+f] of the fraction is ?/2! + ?/3! + ... + ?/f!
[G2] A guard to detect fractional underflow.