CUD

Question

A computer system has 13 bit instruction and support zero address and 1 address instructions.The memory contains 128 words.

If there exists 32 one address instructions how many zero address instructions are supported by system

Answer 1

A computer system has 13 bit instruction , so 2¹³ encodings are possible .

The memory contains 128 words , hence, 7 bits are needed to address each word in memory .

32 one address instructions has 32 * 2⁷ possible encodings = 4096 encodings .

Now, 8192 - 4096 = 4096 possible encodings are remaining , which have no address part, because they are 0 - address instructions. ( only 1 - address and 0 - address instructions are used )

Hence, zero address instructions supported by system are 4096 .