     if mode == 3 { return 0xFF; }
 
     return *(vram + (address & 0x1FFF));
-  }
-
-  // External RAM: $A000 – $BFFF
-  if (address & 0xF000) <= 0xB000 {
-    printf("warn: unhandled read from external ram: $%04X\n", address);
-    return 0xFF;
   }
 
   // Work RAM: $C000 – $DFFF

  } else {
    0;
  }) * 1024;

  // Destination Code
  let dst_code = *(rom + 0x014A);

let wram: *uint8;   // Work RAM – 8 KiB
let oam: *uint8;    // Sprite Attribute Table (OAM) – 160 B
let hram: *uint8;   // High RAM – 127 B
let eram: *uint8;   // External RAM – (defined by cart)

// CPU: State
let is_running = true;
