X-Git-Url: http://git.joshuawise.com/firearm.git/blobdiff_plain/45fa96c0a2fd6e490690cff69dd694a3dce3ab35..2b5c79c05898ff20b0c04cd78bccb2580f6c8331:/BlockRAM.v

diff --git a/BlockRAM.v b/BlockRAM.v
index 85f8659..091c749 100644
--- a/BlockRAM.v
+++ b/BlockRAM.v
@@ -12,29 +12,30 @@ module BlockRAM(
 	 * 0x00004000.  rdata and ready must be driven to zero if the
 	 * address is not within the range of this module.
 	 */
-	wire decode = (bus_addr & ~32'h00003FFF) == 32'h00000000;
-	/* verilator lint_off WIDTH */
-	wire [13:2] ramaddr = bus_addr & 32'h3FFC;	/* mask off lower two bits
+	wire decode = bus_addr[31:14] == 18'b0;
+	wire [13:0] ramaddr = {bus_addr[13:2], 2'b0};	/* mask off lower two bits
 							 * for word alignment */
-	/* verilator lint_on WIDTH */
+
+	reg [31:0] data [(16384 / 4 - 1):0];
 	
-	reg [31:0] data [0:(16384 / 4 - 1)];
-	
-	reg [31:0] temprdata;
-	reg [13:2] lastread;
+	reg [31:0] temprdata = 0;
+	reg [13:0] lastread = 14'h3FFF;
 	assign bus_rdata = (bus_rd && decode) ? temprdata : 32'h0;
 	
 	assign bus_ready = decode &&
 		(bus_wr || (bus_rd && (lastread == ramaddr)));
 	
+	initial
+		$readmemh("ram.hex", data);
+	
 	always @(posedge clk)
 	begin
 		if (bus_wr && decode)
-			data[ramaddr] <= bus_wdata;
+			data[ramaddr[13:2]] <= bus_wdata;
 		
 		/* This is not allowed to be conditional -- stupid Xilinx
 		 * blockram. */
-		temprdata <= data[ramaddr];
+		temprdata <= (bus_wr && decode) ? bus_wdata : data[ramaddr[13:2]];
 		lastread <= ramaddr;
 	end
 endmodule