Connect lower 8 bits of x31 to the LEDs for debugging

rv32.sv

@@ -8,8 +8,14 @@
 `include "rv32_writeback.sv"
 
 module rv32 (
-    input clk
+    input clk,
+    output [7:0] leds
 );
+    always_ff @(posedge clk) begin
+        if (writeback_rd_writeback && writeback_rd == 31)
+            leds <= writeback_rd_value[7:0];
+    end
+
     rv32_fetch fetch (
         .clk(clk),
 

top.sv

@@ -34,6 +34,7 @@ module top (
     );
 
     rv32 rv32 (
-        .clk(clk)
+        .clk(clk),
+        .leds(leds)
     );
 endmodule