UGC NET CSE | June 2012 | Part 3 | Question: 27

Question

Identify the addressing modes of the below instructions and match them :

$\begin{array}{} \text{(a)} & \text{ADI} & \text{(i)} & \text{Immediate addressing} \\  \text{(b)} & \text{STA} & \text{(ii)} & \text{Direct Addressing} \\  \text{(c)}&  \text{CMA} & \text{(iii)}& \text{Implied Addressing} \\  \text{(d)} & \text{SUB} & \text{(iv)}& \text{Register addressing} \\ \end{array}$

• A. $\text{a-i, b-ii, c-iii, d-iv}$
• B. $\text{a-ii, b-i, c-iv, d-iii}$
• C. $\text{a-iii, b-ii, c-i, d-iv}$
• D. $\text{a-iv, b-iii, c-ii, d-i}$

Answer 1

ADI means Add immediate so it is Immediate addressing

STA means copy content of accumulator to the memory location so it is direct addressing

CMA means complement the content of accumulator . The Complement Accumulator (CMA) instruction provides a 1’s complement of the 8 bits in the A register, i.e the 1’s are set to 0’s and the 0’s are set to 1’s.so it is implied

SUB is subtracting so it is register addressing

So ans should be A)