1 files changed, 81 insertions, 0 deletions
diff --git a/scripts/presyn/testbench.v b/scripts/presyn/testbench.v
new file mode 100644
index 0000000..59ff66b
--- /dev/null
+++ b/scripts/presyn/testbench.v
@@ -0,0 +1,81 @@
+module testbench;
+	reg clk = 1;
+	always #5 clk = ~clk;
+
+	reg resetn = 0;
+	always @(posedge clk) resetn <= 1;
+
+	wire        trap;
+	wire        mem_valid;
+	wire        mem_instr;
+	reg         mem_ready;
+	wire [31:0] mem_addr;
+	wire [31:0] mem_wdata;
+	wire [3:0]  mem_wstrb;
+	reg  [31:0] mem_rdata;
+
+	picorv32 UUT (
+		.clk      (clk      ),
+		.resetn   (resetn   ),
+		.trap     (trap     ),
+		.mem_valid(mem_valid),
+		.mem_instr(mem_instr),
+		.mem_ready(mem_ready),
+		.mem_addr (mem_addr ),
+		.mem_wdata(mem_wdata),
+		.mem_wstrb(mem_wstrb),
+		.mem_rdata(mem_rdata)
+	);
+
+	// 4096 32bit words = 16kB memory
+	localparam MEM_SIZE = 4096;
+
+	reg [31:0] memory [0:MEM_SIZE-1];
+	initial $readmemh("firmware.hex", memory);
+
+	always @(posedge clk) begin
+		mem_ready <= 0;
+		mem_rdata <= 'bx;
+
+		if (resetn && mem_valid && !mem_ready) begin
+			mem_ready <= 1;
+			if (mem_wstrb) begin
+				if (mem_addr == 32'h1000_0000) begin
+					$write("%c", mem_wdata[7:0]);
+					$fflush;
+				end else begin
+					if (mem_wstrb[0]) memory[mem_addr >> 2][ 7: 0] <= mem_wdata[ 7: 0];
+					if (mem_wstrb[1]) memory[mem_addr >> 2][15: 8] <= mem_wdata[15: 8];
+					if (mem_wstrb[2]) memory[mem_addr >> 2][23:16] <= mem_wdata[23:16];
+					if (mem_wstrb[3]) memory[mem_addr >> 2][31:24] <= mem_wdata[31:24];
+				end
+			end else begin
+				mem_rdata <= memory[mem_addr >> 2];
+			end
+		end
+
+		if (resetn && trap) begin
+			$display("TRAP.");
+			$finish;
+		end
+	end
+
+	initial begin
+		$dumpfile("testbench.vcd");
+		$dumpvars(0, testbench);
+	end
+endmodule
+
+module picorv32_regs (
+	input [4:0] A1ADDR, A2ADDR, B1ADDR,
+	output reg [31:0] A1DATA, A2DATA,
+	input [31:0] B1DATA,
+	input B1EN, CLK1
+);
+	reg [31:0] memory [0:31];
+	always @(posedge CLK1) begin
+		A1DATA <= memory[A1ADDR];
+		A2DATA <= memory[A2ADDR];
+		if (B1EN) memory[B1ADDR] <= B1DATA;
+	end
+endmodule