Question

If the accumulator of an Intel 8085A microprocessor contains 37 H and the previous operation has set the carry flag, the instruction ACI 56 H will result in ________.

• A. 8E H
• B. 94 H
• C. 7E H
• D. 84 H

Hint:

ACI adds immediate + carry + accumulator. Always convert to decimal, add, and convert back!

Answer 1

The Correct Option is A

Step 1: Understand ACI Instruction
ACI (Add with Carry Immediate) adds an 8-bit immediate value along with the carry flag to the accumulator.
Step 2: Convert Hex to Decimal
- Accumulator = 37H = 55 (decimal)
- Immediate value = 56H = 86 (decimal)
- Carry = 1 (since set)
Step 3: Perform Addition
\[ 55 + 86 + 1 = 142 \] Step 4: Convert Result Back to Hex
142 (decimal) = 8E (hex)
Conclusion:
Option (1) is correct — ACI 56H adds 86 + carry to accumulator, yielding 8E H.