Read ROM size.

src/oboy.ml

@@ -1,9 +1,15 @@
-(** Power up sequence *)
+open Printf
+
+(** Power up sequence
+    http://bgb.bircd.org/pandocs.htm#powerupsequence *)
 let power_up cartridge =
   (** Nintendo logo scrolling *)
   if not (Cartridge.check_nintendo_logo cartridge)
   then print_endline "Invalid ROM."
-  else print_endline "Valid ROM."
+  else
+    print_endline "Valid ROM.";
+    printf "ROM size: %iKB\n" cartridge.rom_size
+
 
 let () =
   if Array.length Sys.argv < 2