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// DESCRIPTION: Verilator: Verilog Test module
//
// This file ONLY is placed under the Creative Commons Public Domain, for
// any use, without warranty, 2008 by Wilson Snyder.
// SPDX-License-Identifier: CC0-1.0
module t (/*AUTOARG*/
// Inputs
clk
);
input clk;
integer cyc = 0;
reg [63:0] crc;
reg [63:0] sum;
// Take CRC data and apply to testblock inputs
wire [31:0] Operand1 = crc[31:0];
wire [15:0] Operand2 = crc[47:32];
wire Unsigned = crc[48];
reg rst;
parameter wl = 16;
/*AUTOWIRE*/
// Beginning of automatic wires (for undeclared instantiated-module outputs)
wire [wl-1:0] Quotient; // From test of Test.v
wire [wl-1:0] Remainder; // From test of Test.v
// End of automatics
Test test (/*AUTOINST*/
// Outputs
.Quotient (Quotient[wl-1:0]),
.Remainder (Remainder[wl-1:0]),
// Inputs
.Operand1 (Operand1[wl*2-1:0]),
.Operand2 (Operand2[wl-1:0]),
.clk (clk),
.rst (rst),
.Unsigned (Unsigned));
// Aggregate outputs into a single result vector
wire [63:0] result = {32'h0, Quotient, Remainder};
// What checksum will we end up with
`define EXPECTED_SUM 64'h98d41f89a8be5693
// Test loop
always @ (posedge clk) begin
`ifdef TEST_VERBOSE
$write("[%0t] cyc==%0d crc=%x result=%x it=%x\n", $time, cyc, crc, result, test.Iteration);
`endif
cyc <= cyc + 1;
if (cyc < 20 || test.Iteration==4'd15) begin
crc <= {crc[62:0], crc[63] ^ crc[2] ^ crc[0]};
end
sum <= result ^ {sum[62:0], sum[63] ^ sum[2] ^ sum[0]};
if (cyc==0) begin
// Setup
crc <= 64'h5aef0c8d_d70a4497;
rst <= 1'b1;
end
else if (cyc<20) begin
sum <= 64'h0;
rst <= 1'b0;
end
else if (cyc<90) begin
end
else if (cyc==99) begin
$write("[%0t] cyc==%0d crc=%x sum=%x\n", $time, cyc, crc, sum);
if (crc !== 64'h8dd70a44972ad809) $stop;
if (sum !== `EXPECTED_SUM) $stop;
$write("*-* All Finished *-*\n");
$finish;
end
end
endmodule
module Test(clk, rst, Operand1, Operand2, Unsigned, Quotient, Remainder);
parameter wl = 16;
input [wl*2-1:0] Operand1;
input [wl-1:0] Operand2;
input clk, rst, Unsigned;
output [wl-1:0] Quotient, Remainder;
reg Cy, Overflow, Sign1, Sign2, Zero, Negative;
reg [wl-1:0] ah,al,Quotient, Remainder;
reg [3:0] Iteration;
reg [wl-1:0] sub_quot,op;
reg ah_ext;
reg [1:0] a,b,c,d,e;
always @(posedge clk) begin
if (!rst) begin
{a,b,c,d,e} = Operand1[9:0];
{a,b,c,d,e} = {e,d,c,b,a};
if (a != Operand1[1:0]) $stop;
if (b != Operand1[3:2]) $stop;
if (c != Operand1[5:4]) $stop;
if (d != Operand1[7:6]) $stop;
if (e != Operand1[9:8]) $stop;
end
end
always @(posedge clk) begin
if (rst) begin
Iteration <= 0;
Quotient <= 0;
Remainder <= 0;
end
else begin
if (Iteration == 0) begin
{ah,al} = Operand1;
op = Operand2;
Cy = 0;
Overflow = 0;
Sign1 = (~Unsigned)&ah[wl-1];
Sign2 = (~Unsigned)&(ah[wl-1]^op[wl-1]);
if (Sign1) {ah,al} = -{ah,al};
end
`define BUG1
`ifdef BUG1
{ah_ext,ah,al} = {ah,al,Cy};
`else
ah_ext = ah[15];
ah[15:1] = ah[14:0];
ah[0] = al[15];
al[15:1] = al[14:0];
al[0] = Cy;
`endif
`ifdef TEST_VERBOSE
$display("%x %x %x %x %x %x %x %x %x",
Iteration, ah, al, Quotient, Remainder, Overflow, ah_ext, sub_quot, Cy);
`endif
{Cy,sub_quot} = (~Unsigned)&op[wl-1]? {ah_ext,ah}+op : {ah_ext,ah} - {1'b1,op};
if (Cy)
begin
{ah_ext,ah} = {1'b0,sub_quot};
end
if (Iteration != 15 )
begin
if (ah_ext) Overflow = 1;
end
else
begin
if (al[14] && ~Unsigned) Overflow = 1;
Quotient <= Sign2 ? -{al[14:0],Cy} : {al[14:0],Cy};
Remainder <= Sign1 ? -ah : ah;
if (Overflow)
begin
Quotient <= Sign2 ? 16'h8001 : {Unsigned,{15{1'b1}}};
Remainder <= Unsigned ? 16'hffff : 16'h8000;
Zero = 1;
Negative = 1;
end
end
Iteration <= Iteration + 1; // Count number of times this instruction is repeated
end
end
endmodule
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