Circuits--Sequential--FSM--q5b~q3a

1. q5b

module top_module (
    input clk,
    input areset,
    input x,
    output  z
); 
    
    parameter A = 1'b0;
    parameter B = 1'b1;
    
    reg[1:0] state;
    reg[1:0] next_state;
 
    
    always@(*)
        begin
            case(state)
                A:
                    if(x) next_state = B;
                	else  next_state = A;
                B:
                    next_state = B;
            endcase
        end
    
    always@(posedge clk or posedge areset)
        begin
            if(areset)
                state = A;
            else
                state = next_state;
        end
    
    always@(*)
        begin
            if(state == A)
                begin
                    if(x)  z = 1'b1;
                    else   z = 1'b0;
                end
                
            else
                begin
                  	if(x) z = 1'b0;
                  	else z = 1'b1;
              	end
        end
 
endmodule

2. q3a

module top_module(
    input clk,
    input reset,
    input s,
    input w,
    output z
);
 
    parameter A = 1'd0;
    parameter B = 1'd1;
    reg[1:0] state;
    reg[1:0] next_state;
    reg[1:0] count;
    reg[1:0] num;
 
    always @(*) begin
        case(state)
            A:
                begin
                    if(s) next_state = B;
                    else  next_state = A;
                end
            B:
                begin
                    next_state = B;
                end
           
        endcase
    end
 
    always @(posedge clk) begin
        if(reset)
            state <= A;
        else
            state <= next_state;
    end
 
    always @(posedge clk) begin
        if(reset)
            count <= 2'd0;
        else if(count == 2'd2)
            count <= 2'd0;
        else if(state == B)
            count <= count + 1'b1;
    end
 
    always @(posedge clk) begin
        if(reset)
            num <= 1'b0;
        else
            begin
                if(count == 2'd0)
                    begin
                        if(w) num <= 1'b1;
                        else num <= 1'b0;
                    end 
                else if(state == B)
                    begin 
                        if(w) num <= num + 1'b1;
                        else  num <= num;
                    end
            end
    end
    assign z = (state == B && num == 2'd2 && count == 2'd0);
endmodule