加减法.txt

实现乘法功能

module counter(clk,clear,n,s,q); 
output[15:0] q; 
input clk,clear,s; 
input[15:0] n; 
reg[15:0] q; 
always@(n) q<=n; 
always @(posedge clk) 
begin 
if (clear) 
q <= 0; 
else 
begin 
if (s) 
begin 
if (q=={16{1'b1}}) q<={16{1'b0}}; 
else q=q+1; 
end 
else 
begin 
if (q=={16{1'b0}}) q<={16{1'b1}}; 
else q<=q-1; 
end 
end 
end 
endmodule