GATE 2020 EE – Question 64

Analog and Digital Electronics · VCOs and timers, combinatorial and sequential logic circuits, multiplexers, demultiplexers · 2 marks · Numerical answer

An 8085 microprocessor accesses two memory locations (2001H) and (2002H), that contain 8-bit numbers 98H and B1H, respectively. The following program is executed:

LXI H,2001H
MVI A,21H
INX H
ADD M
INX H
MOV M,A
HLT

At the end of this program, the memory location 2003H contains the number in decimal (base 10) form ________.

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Correct answer: 210

Explanation

LXI loads HL=2001H, MVI loads A=21H, and INX H makes HL=2002H. ADD M adds the contents of 2002H, B1H, to A: $21\text{H}+\text{B1H}=\text{D2H}$. INX H gives HL=2003H, and MOV M,A stores D2H there. $\text{D2H}=13\times16+2=210$.