cyclonev_mac dsp1
     (
      .ax(ax),
      .ay(ay),
      .az(az),
      .bx(bx[17:0]),
      .by(bx[35:18]),
      .resulta(result)
      );
   
   defparam
     dsp1.operation_mode = "m18x18_plus36",
     dsp1.operand_source_max = "input",
     dsp1.operand_source_may = "preadder",
     dsp1.operand_source_mbx = "input",
     dsp1.ax_width = 18,
     dsp1.ay_scan_in_width = 17,
     dsp1.az_width = 17,
     dsp1.bx_width = 18,
     dsp1.by_width = 18,
     dsp1.result_a_width = 37;