Gate
Gate
Gate
Answer
LHLD 2100H instruction , load lower memory bit to L and higher memory bit to H i.e L
stores the value of memory 2100h
[2014]
Answer:
2. For 8085 microprocessor, the following program is executed [2013]
MVI A, 05H;
MVIB, 05H;
PTR: ADD B;
DCR B;
JNZ PTR;
ADI 03H;
Answer:
3. An 8085 assembly language program is given below. Assume that the carry flag is
initially unset. The content of the accumulator after the execution of the program is
[2011]
4. For the 8085 assembly language program given below, the content of the
accumulator after the execution of the program is [2010]
Answer
STC CY = 1
CMC CY = 0
1:MVI A, B5H
2: MVI B, 0EH
3: XRI 69H
4: ADD B
5: ANI 9BH
6: CPI 9FH
7: STA 3010H
8: HLT
Answer
The contents of the accumulator just after execution of the ADD instruction in line 4 will be
3: XRI 69H ( 69H XOR WITH A) = 0110 1001 XOR 1011 0101 = 1101 1100 (DC H)
CY = 1, Z = 0
DAD H HL = HL + HL = 6140H
ADDRESS LINES A7 A6 A5 A4 A3 A2 A1 A0
D4 1 1 0 1 0 1 0 0
D7 1 1 0 1 0 1 1 1
A2 A3 A4 = 1 0 1 = 5 (OUTPUT)
CALL 3000 H
.
.
3000 H : LXI H, 3CF4 H
PUSH PSW
SPHL
POP PSW
RET
Answer
When SPHL is executed then contents of stack pointer will be 3CF4H. after execution of POP
PSW SP SP+2 & after execution of RET SP SP+2.
so on the completion of RET execution, the contents of SP is 2CF4
3CF8.
10. Consider the sequence of 8085 instructions given below.
LXI H, 9258
MOV A, M,
CMA
MOV M, A
Answer
11. In an 8085 microprocessor, the instruction CMP B has been executed while the
content of the accumulator is less than that of register B. As a result 2003
(a) Carry flag will be set but Zero flag will be reset
(b) Carry flag will be reset but Zero flag will be set
Answer
A-B CY Z
A>B 0 0
A<B 1 0
A=B 0 1
MVI B,87H
MOV A,B
MVI B,00H
XRA B
OUT PORT1
HLT
NEXT: XRA B
JP START
OUT PORT2
HLT
Answer :
Answer : 5
RST 0= 0000H RST 1=0008H RST 2=0010H RST 3=0018H RST 4= 0020H RST 5=0028H RST 6=
0030H RST 7=0038H
15. The contents of Register (B) and Accumulator (A) of 8085 microprocessor are 49H
and 3AH respectively. The contents of A and the status of carry flag (CY) and sign flag (S)
after executing SUB B instructions are
Answer
16 In an 8085 microprocessor, which one of the following instructions changes the content of
the accumulator?
Answer: (D)
Exp: Generally arithmetic or logical instructions update the data of accumulator and flags. So, in
the given option only SBT BE H is arithmetic instruction. SI BEH in accumulator. Add the
content of accumulator with immediate data BE H and store the result.
Instruction [2014]
RAR 2006H
DCR B 2007H
Answer : 60 STEP 1
STEP 2
A = 03 H A = 01 H A = 08 H
STEP 3 STEP 4