FM/MOD FLUSH-FILE FMAX
FM/MOD ( n1.n1 n2 -- m n )  
ansi .6.1.1561 <CORE>
divide the double-cell value n1 by n2 and return both (floored) quotient n and remainder m

reference: p4_f_m_slash_mod in ../src/core.c:1271, export CO FM/MOD