hdlbits 练习汇总
最近发现一个很有意思的网站，可以在线提交 verilog 代码以完成一些任务，并且还能得到仿真结果对比。可以利用零碎时间提交一些代码，练习verilog基础知识。
网址如下：
https://hdlbits.01xz.net/wiki/
从 basics 开始对提交的答案进行汇总。（本博客会不断更新）
//03_Wire.v
module top_module( input in, output out );
assign out = in;
endmodule
//04_Wire4.v
module top_module(
input a,b,c,
output w,x,y,z );
assign w = a;
assign x = b;
assign y = b;
assign z = c;
endmodule
//05_Inverter.v
module top_module( input in, output out );
assign out = ~in;
endmodule
//06_Andgate.v
module top_module(
input a,
input b,
output out );
assign out = a & b;
endmodule
//07_Norgate.v
module top_module(
input a,
input b,
output out );
assign out = ~(a | b);
endmodule
//08_Xnorgate.v
module top_module(
input a,
input b,
output out );
assign out = ~(a ^ b);
endmodule
//09_Wire_decl.v
`default_nettype none
module top_module(
input a,
input b,
input c,
input d,
output out,
output out_n );
wire wire1, wire2, wire3;
assign wire1 = a & b;
assign wire2 = c & d;
assign wire3 = wire1 | wire2;
assign out = wire3;
assign out_n = ~wire3;
endmodule
//10_7458.v
module top_module (
input p1a, p1b, p1c, p1d, p1e, p1f,
output p1y,
input p2a, p2b, p2c, p2d,
output p2y );
wire abc1, def1, ab2, cd2;
assign abc1 = p1c & p1b & p1a;
assign def1 = p1f & p1e & p1d;
assign p1y = abc1 | def1;
assign ab2 = p2a & p2b;
assign cd2 = p2c & p2d;
assign p2y = ab2 | cd2;
endmodule
//11_Vector0.v
module top_module (
input wire [2:0] vec,
output wire [2:0] outv,
output wire o2,
output wire o1,
output wire o0 ); // Module body starts after module declaration
assign outv = vec;
assign o0 = outv[0];
assign o1 = outv[1];
assign o2 = outv[2];
endmodule
//12_7Vector1.v
`default_nettype none // Disable implicit nets. Reduces some types of bugs.
module top_module(
input wire [15:0] in,
output wire [7:0] out_hi,
output wire [7:0] out_lo );
assign out_hi = in[15:8];
assign out_lo = in[7:0];
endmodule
//13_Vector2.v
module top_module(
input [31:0] in,
output [31:0] out );//
// assign out[31:24] = ...;
assign out = {in[7:0], in[15:8], in[23:16], in[31:24]};
endmodule
//14_Vectorgates.v
module top_module(
input [2:0] a,
input [2:0] b,
output [2:0] out_or_bitwise,
output out_or_logical,
output [5:0] out_not
);
assign out_or_bitwise = a | b;
assign out_or_logical = a || b;
assign out_not[5:3] = ~b;
assign out_not[2:0] = ~a;
endmodule
//15_Gates4.v
module top_module(
input [3:0] in,
output out_and,
output out_or,
output out_xor
);
assign out_and = in[0] & in[1] & in[2] & in[3];
assign out_or = in[0] | in[1] | in[2] | in[3];
assign out_xor = in[0] ^ in[1] ^ in[2] ^ in[3];
endmodule
//16_Vector3.v
module top_module (
input [4:0] a, b, c, d, e, f,
output [7:0] w, x, y, z );//
// assign { ... } = { ... };
// assign {w[7:0], x[7:0], y[7:0], z[7:0]} = {a[4:0], b[4:0], c[4:0], d[4:0], e[4:0], f[4:0], 2'b11};
assign {w, x, y, z} = {a, b, c, d, e, f, 2'b11};
endmodule
//17_Vectorr.v
module top_module(
input [7:0] in,
output [7:0] out
);
assign out = {in[0], in[1], in[2], in[3], in[4], in[5], in[6], in[7]};
endmodule
//18_Vector4.v
module top_module (
input [7:0] in,
output [31:0] out );//
// assign out = { replicate-sign-bit , the-input };
assign out = {{24{in[7]}}, in};
endmodule
//19_Vector5.v
module top_module (
input a, b, c, d, e,
output [24:0] out );//
assign out[24:20] = ~ {5{a}} ^ {a, b, c, d, e};
assign out[19:15] = ~ {5{b}} ^ {a, b, c, d, e};
assign out[14:10] = ~ {5{c}} ^ {a, b, c, d, e};
assign out[9:5] = ~ {5{d}} ^ {a, b, c, d, e};
assign out[4:0] = ~ {5{e}} ^ {a, b, c, d, e};
endmodule
//20_Module.v
module top_module ( input a, input b, output out );
mod_a instance1(.out(out), .in1(a), .in2(b));
endmodule
//21_Module_pos.v
module top_module (
input a,
input b,
input c,
input d,
output out1,
output out2
);
mod_a instance1(out1, out2, a, b, c, d);
endmodule
//22_Module_name.v
module top_module (
input a,
input b,
input c,
input d,
output out1,
output out2
);
mod_a instance1(.in1(a), .in2(b), .in3(c), .in4(d), .out1(out1), .out2(out2),);
endmodule
//23_Module_shift.v
module top_module ( input clk, input d, output q );
wire q1, q2;
my_dff instance1(.clk(clk), .d(d), .q(q1));
my_dff instance2(.clk(clk), .d(q1), .q(q2));
my_dff instance3(.clk(clk), .d(q2), .q(q));
endmodule
//24_Module_shift8v.v
module top_module (
input clk,
input [7:0] d,
input [1:0] sel,
output [7:0] q
);
wire [7:0] q1, q2, q3;
my_dff8 instance1(.clk(clk), .d(d), .q(q1));
my_dff8 instance2(.clk(clk), .d(q1), .q(q2));
my_dff8 instance3(.clk(clk), .d(q2), .q(q3));
always @(*) begin
case(sel)
0 : q = d;
1 : q = q1;
2 : q = q2;
3 : q = q3;
endcase
end
endmodule
//25_Module_add.v
module top_module(
input [31:0] a,
input [31:0] b,
output [31:0] sum
);
wire cin1, cout1,cout2;
wire [15:0] sum1, sum2;
assign cin1 = 0;
add16 instance1(.a(a[15:0]), .b(b[15:0]), .cin(cin1), .cout(cout1), .sum(sum1));
add16 instance2(.a(a[31:16]), .b(b[31:16]), .cin(cout1), .cout(cout2), .sum(sum2));
assign sum = {sum2, sum1};
endmodule
//26_Module_fadd.v
module top_module (
input [31:0] a,
input [31:0] b,
output [31:0] sum
);//
wire cin1, cout1, cout2;
wire [15:0] sum1, sum2;
assign cin1 = 0;
add16 instance1(.a(a[15:0]), .b(b[15:0]), .cin(cin1), .cout(cout1), .sum(sum1));
add16 instance2(.a(a[31:16]), .b(b[31:16]), .cin(cout1), .cout(cout2), .sum(sum2));
assign sum = {sum2, sum1};
endmodule
module add1 ( input a, input b, input cin, output sum, output cout );
// Full adder module here
always @(*) begin
if(!cin) begin
if(a == 0 && b == 0) begin
sum = 0;
cout = 0;
end
else if((a == 0 && b == 1) || (a == 1 && b == 0)) begin
sum = 1;
cout = 0;
end
else begin
sum = 0;
cout = 1;
end
end
else begin
if(a == 0 && b == 0) begin
sum = 1;
cout = 0;
end
else if((a == 0 && b == 1) || (a == 1 && b == 0)) begin
sum = 0;
cout = 1;
end
else begin
sum = 1;
cout = 1;
end
end
end
endmodule
//27_Module_cseladd.v
module top_module(
input [31:0] a,
input [31:0] b,
output [31:0] sum
);
wire cin1, cout1, cin2, cout2, cin3, cout3;
wire [15:0] sum1, sum2, sum3, sum_h;
assign cin1 = 0;
assign cin2 = 0;
assign cin3 = 1;
add16 instance1(.a(a[15:0]), .b(b[15:0]), .cin(cin1), .cout(cout1), .sum(sum1));
add16 instance2(.a(a[31:16]), .b(b[31:16]), .cin(cin2), .cout(cout2), .sum(sum2));
add16 instance3(.a(a[31:16]), .b(b[31:16]), .cin(cin3), .cout(cout3), .sum(sum3));
always @(*) begin
case(cout1)
0 : sum_h = sum2;
1 : sum_h = sum3;
endcase
end
assign sum = {sum_h, sum1};
endmodule
//28_Module_addsub.v
module top_module(
input [31:0] a,
input [31:0] b,
input sub,
output [31:0] result
);
wire cout1, cout2;
wire [15:0] sum1, sum2;
wire [31:0] b_xor;
always @(*) begin
if(sub)
b_xor = ~b;
else
b_xor = b;
end
add16 instance1(.a(a[15:0]), .b(b_xor[15:0]), .cin(sub), .cout(cout1), .sum(sum1));
add16 instance2(.a(a[31:16]), .b(b_xor[31:16]), .cin(cout1), .cout(cout2), .sum(sum2));
assign result = {sum2, sum1};
endmodule
//29_Alwaysblock1.v
// synthesis verilog_input_version verilog_2001
module top_module(
input a,
input b,
output wire out_assign,
output reg out_alwaysblock
);
assign out_assign = a & b;
always @(*) out_alwaysblock = a & b;
endmodule
//30_Alwaysblock2.v
// synthesis verilog_input_version verilog_2001
module top_module(
input clk,
input a,
input b,
output wire out_assign,
output reg out_always_comb,
output reg out_always_ff );
assign out_assign = a ^ b;
always @(*) out_always_comb = a ^ b;
always @(posedge clk) out_always_ff <= a ^ b;
endmodule
//31_Always if.v
// synthesis verilog_input_version verilog_2001
module top_module(
input a,
input b,
input sel_b1,
input sel_b2,
output wire out_assign,
output reg out_always );
assign out_assign = (sel_b1 && sel_b2) ? b : a;
always @(*) out_always = (sel_b1 && sel_b2) ? b : a;
endmodule
//32_Always if2.v
// synthesis verilog_input_version verilog_2001
module top_module (
input cpu_overheated,
output reg shut_off_computer,
input arrived,
input gas_tank_empty,
output reg keep_driving ); //
always @(*) begin
if (cpu_overheated)
shut_off_computer = 1;
else
shut_off_computer = 0;
end
always @(*) begin
if (~arrived)
keep_driving = ~gas_tank_empty;
else
keep_driving = 0;
end
endmodule
//33_Always_case.v
// synthesis verilog_input_version verilog_2001
module top_module (
input [2:0] sel,
input [3:0] data0,
input [3:0] data1,
input [3:0] data2,
input [3:0] data3,
input [3:0] data4,
input [3:0] data5,
output reg [3:0] out );//
always@(*) begin // This is a combinational circuit
case(sel)
0 : out = data0;
1 : out = data1;
2 : out = data2;
3 : out = data3;
4 : out = data4;
5 : out = data5;
default : out = 0;
endcase
end
endmodule
//34 Always case2
// synthesis verilog_input_version verilog_2001
module top_module (
input [3:0] in,
output reg [1:0] pos );
integer i;
always@(*)
begin
case(in)
4'd0 : pos = 0;
4'd1 : pos = 0;
4'd2 : pos = 1;
4'd3 : pos = 0;
4'd4 : pos = 2;
4'd5 : pos = 0;
4'd6 : pos = 1;
4'd7 : pos = 0;
4'd8 : pos = 3;
4'd9 : pos = 0;
4'd10 : pos = 1;
4'd11 : pos = 0;
4'd12 : pos = 2;
4'd13 : pos = 0;
4'd14 : pos = 1;
4'd15 : pos = 0;
endcase
end
endmodule
// 35 Always casez
// synthesis verilog_input_version verilog_2001
module top_module (
input [7:0] in,
output reg [2:0] pos );
always @ (*)
begin
casez(in)
8'bzzzzzzz1: pos = 3'd0;
8'bzzzzzz1z: pos = 3'd1;
8'bzzzzz1zz: pos = 3'd2;
8'bzzzz1zzz: pos = 3'd3;
8'bzzz1zzzz: pos = 3'd4;
8'bzz1zzzzz: pos = 3'd5;
8'bz1zzzzzz: pos = 3'd6;
8'b1zzzzzzz: pos = 3'd7;
default: pos = 3'd0;
endcase
end
endmodule
//36 Always nolatches
// synthesis verilog_input_version verilog_2001
module top_module (
input [15:0] scancode,
output reg left,
output reg down,
output reg right,
output reg up );
always@(*)
begin
case(scancode)
16'he06b:
begin
left = 1;
down = 0;
right = 0;
up = 0;
end
16'he072:
begin
left = 0;
down = 1;
right = 0;
up = 0;
end
16'he074:
begin
left = 0;
down = 0;
right = 1;
up = 0;
end
16'he075:
begin
left = 0;
down = 0;
right = 0;
up = 1;
end
default:
begin
left = 0;
down = 0;
right = 0;
up = 0;
end
endcase
end
endmodule