Suppose the word length 16 bits, the main memory contains 64K words, the instruction is as word length and contain only one address. There are 64 instructions in total, please state: (1) If using the direct addressing, how many main memory units can be accessed? (2) If using both direct and indirect addressing, with one bit as the identification for direct or indirect mode, what is the range of main memory that can be accessed? What is the range of main memory that can be accessed by the direct addressing?