Verilog codes for different Shift-registers

Verilog code for an 8-bit shift-left register with a positive-edge clock, serial in and serial out.

 module shift (clk, si, so);
 input        clk,si;
 output       so;
 reg    [7:0] tmp;
 always @(posedge clk)
 begin
    tmp    <= tmp << 1;
    tmp[0] <= si;
 end
    assign so = tmp[7];
        endmodule
        

Verilog code for an 8-bit shift-left register with a negative-edge clock, a clock enable, a serial in and a serial out.

 module shift (clk, ce, si, so);
 input        clk, si, ce;
 output       so;
 reg    [7:0] tmp;
 always @(negedge clk)
 begin
    if (ce) begin
       tmp    <= tmp << 1;
       tmp[0] <= si;
    end
 end
    assign so = tmp[7];
        endmodule
        

Verilog code for an 8-bit shift-left register with a positive-edge clock, asynchronous clear, serial in and serial out.

 module shift (clk, clr, si, so);
 input        clk, si, clr;
 output       so;
 reg    [7:0] tmp;
 always @(posedge clk or posedge clr)
 begin
    if (clr)
       tmp <= 8’b00000000;
    else
       tmp <= {tmp[6:0], si};
 end
    assign so = tmp[7];
        endmodule
        

Verilog code for an 8-bit shift-left register with a positive-edge clock, a synchronous set, a serial in and a serial out.

 module shift (clk, s, si, so);
 input        clk, si, s;
 output       so;
 reg    [7:0] tmp;
 always @(posedge clk)
 begin
    if (s)
       tmp <= 8’b11111111;
    else
       tmp <= {tmp[6:0], si};
 end
    assign so = tmp[7];
        endmodule
        

Verilog code for an 8-bit shift-left register with a positive-edge clock, a serial in and a parallel out.

        module shift (clk, si, po);
        input        clk, si;
        output [7:0] po;
        reg    [7:0] tmp;
        always @(posedge clk)
        begin
           tmp <= {tmp[6:0], si};
        end
           assign po = tmp;
        endmodule
        

Verilog code for an 8-bit shift-left register with a positive-edge clock, an asynchronous parallel load, a serial in and a serial out.

 module shift (clk, load, si, d, so);
 input        clk, si, load;
 input  [7:0] d;
 output       so;
 reg    [7:0] tmp;
 always @(posedge clk or posedge load)
 begin
    if (load) 
              tmp <= d;
    else
       tmp <= {tmp[6:0], si};
 end
    assign so = tmp[7];
        endmodule
        

Verilog code for an 8-bit shift-left register with a positive-edge clock, a synchronous parallel load, a serial in and a serial out.

        module shift (clk, sload, si, d, so);
        input        clk, si, sload;
        input  [7:0] d;
        output       so;
        reg    [7:0] tmp;
        always @(posedge clk)
        begin
           if (sload)
              tmp <= d;
           else
              tmp <= {tmp[6:0], si};
        end
           assign so = tmp[7];
        endmodule
        

Verilog code for an 8-bit shift-left/shift-right register with a positive-edge clock, a serial in and a serial out.

 module shift (clk, si, left_right, po);
 input        clk, si, left_right;
 output       po;
 reg    [7:0] tmp;
 always @(posedge clk)
 begin
    if (left_right == 1’b0)
       tmp <= {tmp[6:0], si};
    else
       tmp <= {si, tmp[7:1]};
 end
    assign po = tmp;
        endmodule