The PERFORM statement executes one or more procedures.  It returns
  control to the end of the PERFORM statement when procedure execution
  ends.

  Format 4 -

   PERFORM [first-proc [ { THRU    } end-proc ]] [ WITH TEST { BEFORE } ]
           [           [ { THROUGH }          ]] [           { AFTER  } ]

      VARYING var FROM init BY increm UNTIL cond

    [ AFTER var FROM init BY increm UNTIL cond ] ...

    [ stment  END-PERFORM ]

1 - first-proc

  is a procedure-name that identifies a paragraph or section in the
  Procedure Division.  The set of  statements in first-proc are the
  first (or only) set of statements in the PERFORM range.

2 - end-proc

  is a procedure-name that identifies a paragraph or section in the
  Procedure Division.  The set of statements in end-proc are the last
  set of statements in the PERFORM range.

3 - stment

  is an imperative statement.

4 - cond

  can be any conditional expression.

5 - var

  is an index-name or the identifier of a numeric elementary data item.
  Its value is changed by increm each time all statements in the
  PERFORM range execute.

6 - init

  is a numeric literal, index-name, or the identifier of a numeric
  elementary data item.  It specifies the value of var before any
  statement in the PERFORM range executes.

7 - increm

  is a nonzero numeric literal or the identifier of a numeric
  elementary data item.  It systematically changes the value of var
  each time the program executes all statements in the PERFORM range.