simple-risc-processor/StackPointer.v at main · nasri-attari/simple-risc-processor · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
`include "constants.v"

module stackPointer(clock, SP, newSP, empty, full);

    input wire clock;

    output reg [31:0] SP;

	output reg  empty, full;

	input wire [1:0] newSP;


    // SP + 1
    wire [31:0] SPPlus1;
	assign  SPPlus1 = SP + 32'd1;

	// SP - 1
    wire [31:0] SPMin1;
	assign  SPMin1 = SP - 32'd1;

	initial begin
		SP <= 32'd222;
		empty = 1'b1 ;
		full = 1'b0	;
	end


	always @(posedge clock) begin

		if (SP == 32'd222) begin
            empty <= 1'b1;
        end

		else begin
            empty <= 1'b0;
        end

        if (SP == 32'd256) begin
            full <= 1'b1;
        end
		else begin
            full <= 1'b0;
        end

	end


    always @(posedge clock) begin
        case (newSP)

            stackPointerDef: begin
                // Do nothing
            end

            stackPointerPop: begin
                // SP = SP - 1
                SP = SPMin1;
            end

			 stackPointerPush: begin
                // SP = SP + 1
                SP = SPPlus1;
            end

        endcase
	end

endmodule