What this program is going to do?

[vashwath@rediffmail.com (prashna)]

function PART_ENT (
         X : in     FLOAT ) 
     return FLOAT is 
      R : FLOAT;  
   begin
      -- Attention imprecision pour .5
      R := FLOAT (INTEGER (abs X));

      -- Round to Zero afin de corriger l'imprecision
      if R > abs X then
         R := R - 1.0;
      end if;

      -- Signe du resultat
      if X >= 0.0 then
         return R;
      else
         return - R;
      end if;
   end PART_ENT;
I found this program in source code of my project(code review).Can any
one explain what this program does?