Function GASDEV(IDUM&)
    Static ISET, GSET
    If ISET = 0 Then
      Do
        V1 = 2# * RAN1(IDUM&) - 1#
        V2 = 2# * RAN1(IDUM&) - 1#
        R = V1 ^ 2 + V2 ^ 2
      Loop While R >= 1# Or R = 0
      FAC = Sqr(-2# * Log(R) / R)
      GSET = V1 * FAC
      GASDEV = V2 * FAC
      ISET = 1
    Else
      GASDEV = GSET
      ISET = 0
    End If
End Function