Document interval div

Author: sim642

src/cdomain/value/cdomains/intDomain0.ml

@@ -361,6 +361,12 @@ module IntervalArith (Ints_t : IntOps.IntOps) = struct
     let y2p = Ints_t.shift_left Ints_t.one y2 in
     mul (x1, x2) (y1p, y2p)
 
+  (** Divide mathematical intervals.
+      Excludes 0 from denominator - must be handled as desired by caller.
+
+      @return negative and positive denominator cases separately, if they exist.
+
+      @see <https://mine.perso.lip6.fr/publi/article-mine-FTiPL17.pdf> Miné, A. Tutorial on Static Inference of Numeric Invariants by Abstract Interpretation. Figure 4.6. *)
   let div (a, b) (c, d) =
     let pos =
       if Ints_t.(compare one d) <= 0 then