Simulate problem about (altfp_sqrt) core

ddr ddr_sqrt (
     .clock(clk),
     .data(idin),
     .result(dout)
      );

Check that your MegaWizard generated altfp_sqrt module instance is indeed named "ddr".

thank you . but I checked the altfp_sqrt module name is right.

And I re-do the whole program, it still has the same problem.

/***************Top Module ****************/

module fp_sqrt (clk, idin, dout);

input clk;

input [31:0] idin;

output [31:0] dout;

wire [31:0] idin;

wire [31:0] dout;

sel_sq fp_sqrt_sq (

.clock(clk),

.data(idin),

.result(dout)

);

always @ (posedge clk)

begin

$display ("idin= ", idin);

$display ("dout = ", dout);

end

endmodule

/****************ALTFP_SQRT CORE********************/

// megafunction wizard: %ALTFP_SQRT%VBB%

// GENERATION: STANDARD

// VERSION: WM1.0

// MODULE: altfp_sqrt

// ============================================================

// File Name: sel_sq.v

// Megafunction Name(s):

// altfp_sqrt

//

// Simulation Library Files(s):

// lpm

// ============================================================

// ************************************************************

// THIS IS A WIZARD-GENERATED FILE. DO NOT EDIT THIS FILE!

//

// 10.1 Build 197 01/19/2011 SP 1 SJ Full Version

// ************************************************************

//Copyright (C) 1991-2011 Altera Corporation

//Your use of Altera Corporation's design tools, logic functions

//and other software and tools, and its AMPP partner logic

//functions, and any output files from any of the foregoing

//(including device programming or simulation files), and any

//associated documentation or information are expressly subject

//to the terms and conditions of the Altera Program License

//Subscription Agreement, Altera MegaCore Function License

//Agreement, or other applicable license agreement, including,

//without limitation, that your use is for the sole purpose of

//programming logic devices manufactured by Altera and sold by

//Altera or its authorized distributors. Please refer to the

//applicable agreement for further details.

module sel_sq (

clock,

data,

result)/* synthesis synthesis_clearbox = 1 */;

input clock;

input [31:0] data;

output [31:0] result;

endmodule

/**********************testbench*************************/

module fp_sqrt (clk, idin, dout);

input clk;

input [31:0] idin;

output [31:0] dout;

wire [31:0] idin;

wire [31:0] dout;

sel_sq fp_sqrt_sq (

.clock(clk),

.data(idin),

.result(dout)

);

always @ (posedge clk)

begin

$display ("idin= ", idin);

$display ("dout = ", dout);

end

endmodule