You use Altera's megafunction to generate the "DIVIDER" wizard, now you will see like that follows:
// megafunction wizard: %LPM_DIVIDE%
// GENERATION: STANDARD
// VERSION: WM1.0
// MODULE: lpm_divide
// ============================================================
// File Name: div31.v
// Megafunction Name(s):
// lpm_divide
//
// Simulation Library Files(s):
// lpm
// ============================================================
// ************************************************************
// THIS IS A WIZARD-GENERATED FILE. DO NOT EDIT THIS FILE!
//
// 7.1 Build 178 06/25/2007 SP 1 SJ Full Version
// ************************************************************
//Copyright (C) 1991-2007 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.
// synopsys translate_off
`timescale 1 ps / 1 ps
// synopsys translate_on
module div31 (
clock,
denom,
numer,
quotient,
remain);
input clock;
input [15:0] denom;
input [30:0] numer;
output [30:0] quotient;
output [15:0] remain;
wire [30:0] sub_wire0;
wire [15:0] sub_wire1;
wire [30:0] quotient = sub_wire0[30:0];
wire [15:0] remain = sub_wire1[15:0];
lpm_divide lpm_divide_component (
.denom (denom),
.clock (clock),
.numer (numer),
.quotient (sub_wire0),
.remain (sub_wire1),
.aclr (1'b0),
.clken (1'b1));
defparam
lpm_divide_component.lpm_drepresentation = "SIGNED",
lpm_divide_component.lpm_hint = "LPM_REMAINDERPOSITIVE=TRUE",
lpm_divide_component.lpm_nrepresentation = "SIGNED",
lpm_divide_component.lpm_pipeline = 1,
lpm_divide_component.lpm_type = "LPM_DIVIDE",
lpm_divide_component.lpm_widthd = 16,
lpm_divide_component.lpm_widthn = 31;
endmodule
// ============================================================
// CNX file retrieval info
// ============================================================
// Retrieval info: PRIVATE: INTENDED_DEVICE_FAMILY STRING "Stratix II"
// Retrieval info: PRIVATE: PRIVATE_LPM_REMAINDERPOSITIVE STRING "TRUE"
// Retrieval info: PRIVATE: PRIVATE_MAXIMIZE_SPEED NUMERIC "-1"
// Retrieval info: PRIVATE: SYNTH_WRAPPER_GEN_POSTFIX STRING "0"
// Retrieval info: PRIVATE: USING_PIPELINE NUMERIC "1"
// Retrieval info: PRIVATE: VERSION_NUMBER NUMERIC "2"
// Retrieval info: CONSTANT: LPM_DREPRESENTATION STRING "SIGNED"
// Retrieval info: CONSTANT: LPM_HINT STRING "LPM_REMAINDERPOSITIVE=TRUE"
// Retrieval info: CONSTANT: LPM_NREPRESENTATION STRING "SIGNED"
// Retrieval info: CONSTANT: LPM_PIPELINE NUMERIC "1"
// Retrieval info: CONSTANT: LPM_TYPE STRING "LPM_DIVIDE"
// Retrieval info: CONSTANT: LPM_WIDTHD NUMERIC "16"
// Retrieval info: CONSTANT: LPM_WIDTHN NUMERIC "31"
// Retrieval info: USED_PORT: clock 0 0 0 0 INPUT NODEFVAL clock
// Retrieval info: USED_PORT: denom 0 0 16 0 INPUT NODEFVAL denom[15..0]
// Retrieval info: USED_PORT: numer 0 0 31 0 INPUT NODEFVAL numer[30..0]
// Retrieval info: USED_PORT: quotient 0 0 31 0 OUTPUT NODEFVAL quotient[30..0]
// Retrieval info: USED_PORT: remain 0 0 16 0 OUTPUT NODEFVAL remain[15..0]
// Retrieval info: CONNECT: @numer 0 0 31 0 numer 0 0 31 0
// Retrieval info: CONNECT: @denom 0 0 16 0 denom 0 0 16 0
// Retrieval info: CONNECT: quotient 0 0 31 0 @quotient 0 0 31 0
// Retrieval info: CONNECT: remain 0 0 16 0 @remain 0 0 16 0
// Retrieval info: CONNECT: @clock 0 0 0 0 clock 0 0 0 0
// Retrieval info: LIBRARY: lpm lpm.lpm_components.all
// Retrieval info: GEN_FILE: TYPE_NORMAL div31.v TRUE
// Retrieval info: GEN_FILE: TYPE_NORMAL div31.inc FALSE
// Retrieval info: GEN_FILE: TYPE_NORMAL div31.cmp TRUE
// Retrieval info: GEN_FILE: TYPE_NORMAL div31.bsf TRUE
// Retrieval info: GEN_FILE: TYPE_NORMAL div31_inst.v TRUE
// Retrieval info: GEN_FILE: TYPE_NORMAL div31_bb.v TRUE
// Retrieval info: LIB_FILE: lpm
--------------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------------
The Question is: we can't use this wizard to synthesize by DC, thereforce, we must use verilog to design the divider by ourself.
Another method is as follow:
// MODULE DECLARATION
module lpm_divide (
numer, // The numerator (Required)
denom, // The denominator (Required)
clock, // Clock input for pipelined usage
aclr, // Asynchronous clear signal
clken, // Clock enable for pipelined usage.
quotient, // Quotient (Required)
remain // Remainder (Required)
);
// GLOBAL PARAMETER DECLARATION
parameter lpm_widthn = 31; // Width of the numer[] and quotient[] port. (Required)
parameter lpm_widthd = 16; // Width of the denom[] and remain[] port. (Required)
parameter lpm_nrepresentation = "SIGNED"; // The representation of numer
parameter lpm_drepresentation = "SIGNED"; // The representation of denom
parameter lpm_pipeline = 1; // Number of Clock cycles of latency
parameter lpm_type = "LPM_DIVIDE";
parameter lpm_hint = "LPM_REMAINDERPOSITIVE=TRUE";
// INPUT PORT DECLARATION
input [lpm_widthn-1:0] numer;
input [lpm_widthd-1:0] denom;
input clock;
input aclr;
input clken;
// OUTPUT PORT DECLARATION
output [lpm_widthn-1:0] quotient;
output [lpm_widthd-1:0] remain;
// INTERNAL REGISTER/SIGNAL DECLARATION
reg [lpm_widthn-1:0] quotient_pipe [lpm_pipeline+1:0];
reg [lpm_widthd-1:0] remain_pipe [lpm_pipeline+1:0];
reg [lpm_widthn-1:0] tmp_quotient;
reg [lpm_widthd-1:0] tmp_remain;
reg [lpm_widthn-1:0] not_numer;
reg [lpm_widthn-1:0] int_numer;
reg [lpm_widthd-1:0] not_denom;
reg [lpm_widthd-1:0] int_denom;
reg [lpm_widthn-1:0] t_numer;
reg [lpm_widthn-1:0] t_q;
reg [lpm_widthd-1:0] t_denom;
reg [lpm_widthd-1:0] t_r;
reg sign_q;
reg sign_r;
reg sign_n;
reg sign_d;
reg [8*5:1] lpm_remainderpositive;
// LOCAL INTEGER DECLARATION
integer i;
integer rsig;
integer pipe_ptr;
// INTERNAL TRI DECLARATION
tri0 aclr;
tri0 clock;
tri1 clken;
wire i_aclr;
wire i_clock;
wire i_clken;
buf (i_aclr, aclr);
buf (i_clock, clock);
buf (i_clken, clken);
// COMPONENT INSTANTIATIONS
LPM_HINT_EVALUATION eva();
// INITIAL CONSTRUCT BLOCK
initial
begin
// check if lpm_widthn > 0
if (lpm_widthn <= 0)
begin
$display("Error! LPM_WIDTHN must be greater than 0.\n");
$finish;
end
// check if lpm_widthd > 0
if (lpm_widthd <= 0)
begin
$display("Error! LPM_WIDTHD must be greater than 0.\n");
$finish;
end
// check for valid lpm_nrepresentation value
if ((lpm_nrepresentation != "SIGNED") && (lpm_nrepresentation != "UNSIGNED"))
begin
$display("Error! LPM_NREPRESENTATION value must be \"SIGNED\" or \"UNSIGNED\".");
$finish;
end
// check for valid lpm_drepresentation value
if ((lpm_drepresentation != "SIGNED") && (lpm_drepresentation != "UNSIGNED"))
begin
$display("Error! LPM_DREPRESENTATION value must be \"SIGNED\" or \"UNSIGNED\".");
$finish;
end
// check for valid lpm_remainderpositive value
lpm_remainderpositive = eva.GET_PARAMETER_VALUE(lpm_hint, "LPM_REMAINDERPOSITIVE");
if ((lpm_remainderpositive == "TRUE") &&
(lpm_remainderpositive == "FALSE"))
begin
$display("Error! LPM_REMAINDERPOSITIVE value must be \"TRUE\" or \"FALSE\".");
$finish;
end
for (i = 0; i <= (lpm_pipeline+1); i = i + 1)
begin
quotient_pipe[i] <= {lpm_widthn{1'b0}};
remain_pipe[i] <= {lpm_widthd{1'b0}};
end
pipe_ptr = 0;
end
// ALWAYS CONSTRUCT BLOCK
always @(numer or denom or lpm_remainderpositive)
begin
sign_q = 1'b0;
sign_r = 1'b0;
sign_n = 1'b0;
sign_d = 1'b0;
t_numer = numer;
t_denom = denom;
if (lpm_nrepresentation == "SIGNED")
if (numer[lpm_widthn-1] == 1'b1)
begin
t_numer = ~numer + 1; // numer is negative number
sign_n = 1'b1;
end
if (lpm_drepresentation == "SIGNED")
if (denom[lpm_widthd-1] == 1'b1)
begin
t_denom = ~denom + 1; // denom is negative numbrt
sign_d = 1'b1;
end
t_q = t_numer / t_denom; // get quotient
t_r = t_numer % t_denom; // get remainder
sign_q = sign_n ^ sign_d;
sign_r = (t_r != {lpm_widthd{1'b0}}) ? sign_n : 1'b0;
// Pipeline the result
tmp_quotient = (sign_q == 1'b1) ? (~t_q + 1) : t_q;
tmp_remain = (sign_r == 1'b1) ? (~t_r + 1) : t_r;
// Recalculate the quotient and remainder if remainder is negative number
// and LPM_REMAINDERPOSITIVE=TRUE.
if ((sign_r) && (lpm_remainderpositive == "TRUE"))
begin
tmp_quotient = tmp_quotient + ((sign_d == 1'b1) ? 1 : -1 );
tmp_remain = tmp_remain + t_denom;
end
end
always @(posedge i_clock or posedge i_aclr)
begin
if (i_aclr)
begin
for (i = 0; i <= (lpm_pipeline+1); i = i + 1)
begin
quotient_pipe[i] <= {lpm_widthn{1'b0}};
remain_pipe[i] <= {lpm_widthd{1'b0}};
end
pipe_ptr <= 0;
end
else if (i_clken)
begin
quotient_pipe[pipe_ptr] <= tmp_quotient;
remain_pipe[pipe_ptr] <= tmp_remain;
if (lpm_pipeline > 1)
pipe_ptr <= (pipe_ptr + 1) % lpm_pipeline;
end
end
// CONTINOUS ASSIGNMENT
assign quotient = (lpm_pipeline > 0) ? quotient_pipe[pipe_ptr] : tmp_quotient;
assign remain = (lpm_pipeline > 0) ? remain_pipe[pipe_ptr] : tmp_remain;
endmodule // lpm_divide
// END OF MODULE
