(42S) Big Factorial

[Werner]

A quick hack to see if it could be done:
All in the stack, with an automatically growing matrix.
I add a zero to the end (right) of the carry matrix with GROW J+, positioned at the end.
I shift the carry matrix left with a DELR if the leftmost carry is zero, else I enlarge the
value matrix with an INSR, adding a zero to the left.
The 1E10 can be calculated if needed, to be as large as possible without overflowing.

00 { 70-Byte Prgm }
01▸LBL "BIG!"
02 1
03 ENTER
04 NEWMAT
05 1
06 +
07 1ᴇ10
08 X<>Y
09▸LBL 02
10 RCL ST Z
11 ×
12 RCL ST Y
13 ÷
14 ENTER
15 FP
16 STO- ST Y
17 RCL× ST Z
18 X<>Y
19 EDIT
20 J-
21 GROW
22 J+
23 I+
24 X=0?
25 GTO 00
26 EXITALL
27 X<>Y
28 EDIT
29 INSR
30 GTO 01
31▸LBL 00
32 DELR
33▸LBL 01
34 EXITALL
35 +
36 DSE ST Z
37 GTO 02
38 END

Cheers, Werner