Writing in assembly language, was able to get this to work for numbers up to $6$ factorial, I need it to work to for N factorial and for N$=9$ and higher must correctly calculate lowest two bytes. It must match the c pseudocode, which I've written and therefore can be changed, $1-$to$-1.$ The pseudocode must use two nested loops and can only use if$/$while$/$do$-$until loops, no for loops. You also cannot use the MUL instruction, must add together as in pseudocode. Only thing that cant be changed are these parts:

$*$ start of data section

ORG $B$000$

N FCB $8$

ORG $B$010$

NFAC RMB $2$

$*$ define any other variables that you might need here

ORG $C$000$

$*$ start of your program