The EXIT statement terminates execution of a DO construct.
  Statement format:

     EXIT [name]

     name  Is the name of the DO construct.

  The EXIT statement causes execution of the named (or innermost) DO
  construct to be terminated.

  If a DO construct name is specified, the EXIT statement must be
  within the range of that construct.

  Any DO variable present retains its last defined value.

  An EXIT statement can be labeled, but it cannot be used to
  terminate a DO construct.

  The following example shows an EXIT statement:

  LOOP_A : DO I = 1, 15
    N = N + 1
    IF (N > I) EXIT LOOP_A
  END DO LOOP_A