fifofile.v

FIFO电路Verilog实现

module fifo(clk,rstp,din,writep,readp,dout,emptyp,fullp);
input clk;
input rstp ;
input[15:0] din;
input readp;
input writep;
output[15:0] dout;
output emptyp;
output fullp;

parameter DEPTH=2,MAX_COUNT=2'b11;

reg[15:0] dout;
reg emptyp;
reg fullp;

reg[(DEPTH-1):0] tail;
reg[(DEPTH-1):0]  head;
reg[(DEPTH-1):0] count;
reg[15:0] fifomem[0:MAX_COUNT];

always@(posedge clk)
begin
    if(rstp==1)
    begin
        dout<=16'h0000;
    end
    else if(readp==1'b1&&emptyp==1'b0)
    begin
        dout<=fifomem[tail];
    end
end

always@(posedge clk)
begin
    if(rstp==1'b0&&writep==1'b1&&fullp==1'b0)
    begin
        fifomem[head]<=din;
    end
end

//update head pointer
always@(posedge clk)
begin
    if(rstp==1'b1)
    begin
        head<=2'b00;
    end
    else
    begin
        if(writep==1'b1&&fullp==1'b0)
        begin
            head<=head+1;
        end
    end
end


//update tail pointer
always@(posedge clk)
    
    begin
      if(rstp==1'b1) 
      begin 
        tail<=2'b00;
    end
    else
    begin
        if(readp==1'b1&&emptyp==1'b0)
        begin
            tail<=tail+1;
        end
    end
end

//update counter
always@(posedge clk)
begin
    if(rstp==1'b1)
    begin
        count<=2'b00;
    end
else
begin
    case({readp,writep})
        2'b00:
        count<=count;
        
        2'b01:
        if(count!=MAX_COUNT)
        count<=count+1;
        2'b10:
        if(count!=2'b00)
        count<=count-1;
        2'b11:
        count<=count;
endcase
end
end


//update emptyp log
always@(count)
begin
    if(count==2'b00)
    emptyp<=1'b1;
    else
    emptyp<=1'b0;
end

//update fullp log
always@(count)
begin
    if(count==MAX_COUNT)
    fullp<=1'b1;
    else
    fullp<=1'b0;
end
endmodule