Import "" ;msvcrt.lib
  AbsI(Quad.q) As "_abs64"
  AbsL(Long.l) As "labs"
EndImport
Procedure.i GCD(u.i, v.i)
  Protected.i t
  While v <> 0
    t = v
    v = u % v
    u = t
  Wend
  ProcedureReturn AbsI(u) ; Avoid float conversion with Abs(u).
EndProcedure
Debug GCD(18,    12)     ; 6
Debug GCD(1071,  1029)   ; 21
Debug GCD(3528,  -3780)  ; 252