: sqrt
i loc1 sto
i loc1 sto
i mark2 dup
i loc0 sto
c /2
i loc1 sto
% loop
i loc0 lod
i loc1 lod
c newton
i dup loc1
c replace!
c thresh
c close?
b loop
i loc1 lod
i ret2

: newton
c tuck
c square
i add div
c /2
i ret0