Int E0 Fn 0023  - Pcrobots V1.41 - "get_shell_status" - Find Out What Hap  [g]

   AX = 0023h

Return: BX = status of last shell to land
       0000h missed completely
       0001h hit a wall
       0002h hit a robot within 50-square radius
       0003h hit a robot within 25-square radius
       0004h hit a robot within 5-square radius