练习：设计一个带控制端的逻辑运算电路，分别完成正整数的平方、立方和阶乘的运算。
//--------------myfunction----------
modulemyfunction(clk,n,result,reset,sl);
output[6:0]result;
input[2:0] n;
input reset,clk;
input [1:0] sl;
reg[6:0]result;//define input and output
always @(posedgeclk)
begin
if(!reset)
result<=0;
else
begin
case(sl)
2'd0:result<=square(n);
2'd1:result<=cubic(n);
2'd2:result<=factorial(n);
endcase
end
end
function[6:0]square;
input [2:0]operand;
begin
square=operand*operand;
end
endfunction
function[6:0]cubic;
input [2:0]operand;
begin
cubic=operand*operand*operand;
end
endfunction
function[6:0]factorial;
input [2:0]operand;
reg [2:0] index;
begin
factorial = 1 ;
for(index = 2; index <= operand; index =index + 1)
factorial = index * factorial;
end
endfunction
endmodule
//--------------testmyfunc----------
`include"./myfunction.v"
`timescale1ns/100ps
`define clk_cycle50
module testmyfunc;
reg[2:0] n;
reg reset,clk;
reg[1:0] sl;
wire[6:0] result;
parametertimes=20;
initial
begin
n=0;
reset=1;
clk=0;
sl=0;
#100 reset=0;
#100 reset=1;
repeat(times)
begin
#50sl={$random}%3;
#50 n={$random}%6;
end
#1000 $stop;
end
always #`clk_cycleclk=~clk;
myfunctionmyfunct(.clk(clk),.n(n),.result(result),.reset(reset),.sl(sl));
endmodule