A certain machine has 16-bit instructions and 6-bit addresses. Some instructions have one address and others have two. If there are n two-address instructions, what is the maximum number of one-address instructions?
Answers
The maximum number of one-address instructions will be 26 bits.
Explanation:
Each byte of a machine or main storage involves an address that is known as bit address.
One address instructions exists in the accumulator and in the memory location.
According to the question,
There are 16-bits for instructions and 6-bits for addresses.
Therefore, no. of encoding will be 2^16.
Since, there are 6-bit addresses used, and as per given in the question, there are n two address instructions, it would be 2^6×2^6×n as encoding.
Now, as given, one address and two address instructions are there in the question. So, the remaining encoding that has to be used for one address instruction will be 2^16 − 2^12 * n that will correspond to:
(2^16−2^12×n) /26 = 2^10−n*2^6
Hence, the maximum number of one-address instructions will be 26 bits.