`include "pll.v"
`include "ram.v"
`include "chip.v"
`include "uart.v"

`ifdef SIM
 `define UART_DIVIDE 1
`else
 `define UART_DIVIDE 1
 // s/192/3/ for 19200 baud uart
`endif

module worker (input CLKin, output [4:0] led, output uart_tx, input uart_rx, output reg ready_out = 1, input ready_in);
   wire clk;
   wire clk_tmp;

   //pll pll (.clock_in(CLKin), .clock_out(clk));

   reg [20:0] counter = 0;

   reg 		  clk = 0;

   always @ (posedge CLKin) begin
	  if(counter == 5000) begin
		 counter <= 0;
		 clk <= 1 - clk;
	  end
	  else
		counter <= counter + 1;
   end

   wire [11:0] mem_addr;
   wire [15:0] mem_in;
   wire [15:0] mem_out;
   wire 	   mem_write;

   RAM #(.ADDRESS_BITS(8)) ram (.clk(clk), .write(mem_write), .addr(mem_addr), .in(mem_in), .out(mem_out));

   reg [7:0]   from_uart [3:0];
   reg [2:0]   uart_ptr = 0;

   wire [15:0] I  = {from_uart[1], from_uart[0]};
   assign mem_addr = from_uart[2];
   wire [2:0]  op_from_uart = from_uart[3][2:0];
   wire 	   CS = from_uart[3][3];

   /* to execute a ROUTE instruction, we send our neighbour a STOREI
   /* instruction with the correct address and value. This is the
   /* STOREI instruction. */
   wire [7:0]  route_storei [3:0];
   assign route_storei[0] = mem_out[7:0];
   assign route_storei[1] = mem_out[15:8];
   assign route_storei[2] = from_uart[0];
   assign route_storei[3] = 3'd4; // OP_STOREI

   reg [2:0]   op = 0;

   reg [2:0]   last_op = 0;

   reg [15:0]  I;
   reg 		   CS;

   reg [3:0]   led_out;

   chip chip (.clk(clk), .op(op), .I(I), .io_pin(0), .CS(CS), .mem_in(mem_in), .mem_out(mem_out), .mem_write(mem_write), .led_out(led_out));

   wire 	   received;
   wire [7:0]  rx_byte;
   reg 		   transmit = 0;
   reg  [7:0]  tx_byte = 0;
   wire 	   is_receiving;
   wire 	   is_transmitting;

   // 19200 (actually 300) baud uart
   uart #(.CLOCK_DIVIDE(`UART_DIVIDE)) uart (.clk(clk), .rx(uart_rx), .tx(uart_tx), .received(received), .transmit(transmit), .tx_byte(tx_byte), .rx_byte(rx_byte), .is_receiving(is_receiving), .is_transmitting(is_transmitting));

`define STATE_IDLE 0
`define STATE_PROPAGATE 1
`define STATE_EXECUTE 2
`define STATE_ROUTE 3

   reg [5:0]   state = `STATE_IDLE;

   assign led[3:0] = led_out;
   assign led[4] = 0;

   always @ (posedge clk) begin
	  case(state)
		`STATE_IDLE: begin
		   if(uart_ptr == 4) begin
			  last_op <= op_from_uart;
			  uart_ptr <= 0;
			  state <= `STATE_PROPAGATE;
			  ready_out <= 0;
		   end
		   else	if (received) begin
			  from_uart[uart_ptr] <= rx_byte;
			  uart_ptr <= uart_ptr + 1;
		   end else
			 ready_out <= 1;
		end

		`STATE_PROPAGATE: begin
		   if(transmit)
			  transmit <= 0;
		   else if(uart_ptr == 4) begin
			  uart_ptr <= 0;
			  the_leds <= last_op;
			  if(last_op == `OP_ROUTE) begin
				 state <= `STATE_ROUTE;
			  end else begin
				 op <= last_op;
				 state <= `STATE_EXECUTE;
			  end
		   end else if(!is_transmitting && ready_in) begin
			  tx_byte <= from_uart[uart_ptr];
			  transmit <= 1;
			  uart_ptr <= uart_ptr + 1;
		   end
		end

		`STATE_EXECUTE: begin
		   op <= 0;
		   state <= `STATE_IDLE;
		end

		`STATE_ROUTE: begin
		   if(transmit)
			  transmit <= 0;
		   else if(uart_ptr == 4) begin
			  uart_ptr <= 0;
			  state <= `STATE_IDLE;
		   end else if(!is_transmitting && ready_in) begin
			  tx_byte <= route_storei[uart_ptr];
			  transmit <= 1;
			  uart_ptr <= uart_ptr + 1;
		   end
		end
	  endcase
   end

//   wire ready = (state == 0 && !is_receiving);
endmodule