Brain-like logic using Verilog

brain.v

module brain (clk, sensor, effect);
	parameter nbit = 12;
	parameter size = 2 ** nbit;

	input clk;
	input [7:0] sensor;
	output [7:0] effect;

	reg sig [0:size - 1];
	reg trace [0:size - 1];
	reg [nbit - 1:0] ram [0:size - 1];

	assign effect[3:0] = {sig[3], sig[2], sig[1], sig[0]};
	assign effect[7:4] = {sig[7], sig[6], sig[5], sig[4]};

	integer i;

	initial for (i = 0; i < size; i = i + 1) begin
		trace[i] = 0;
		sig[i] = 0;
		ram[i] = i;
	end

	always @(posedge clk) begin
		for (i = 0; i < 8; i = i + 1)
			sig[ram[i]] <= sensor[i];

		for (i = 0; i < size; i = i + 1) begin
			case ({trace[i], sig[ram[i]]})
			2'b00: ram[i] <= ram[i] + 1;
			2'b01: sig[i] <= 1;
			2'b10: sig[i] <= 0;
			2'b11: ram[i] <= ram[i] - 1;
			endcase

			trace[i] <= sig[ram[i]];
		end
	end
endmodule

`ifdef SIM
module sim;
	reg clk = 0;
	reg [7:0] key;
	wire [7:0] led;

	brain core(clk, key, led);

	integer c;

	always begin
		c = $fgetc(32'h8000_0000);
		if (-1 == c)
			$finish;

		key = c[7:0];
		#1 clk = ~clk;
		#1 clk = ~clk;
		$displayb(led);
	end
endmodule
`endif

Makefile

all: brain
	base64 /dev/urandom | head | ./brain

clean:
	-rm -f brain

.SUFFIXES: .v

.v:
	iverilog -Wall -DSIM -o $@ $<