Page 141 - DCAP210_INTRODUCTION__TO_MICROPROCESSORS

Unit 9: Introduction to 8085 Instructions

2. The instruction INR use to: Notes

(a) Decrement specified byte by one (b) Increment register pair by one
(c) Increment specified byte by one (d) Decrement register pair by one
3. The instruction INX use to:

(a) Decrement specified byte by one (b) Increment register pair by one
(c) Increment specified byte by one (d) Decrement register pair by one
4. The instruction DCX use to:
(a) Decrement specified byte by one (b) Increment register pair by one

(c) Increment specified byte by one (d) Decrement register pair by one
5. The instruction CMP use to:

(a) Decrement specified byte by one (b) Increment register pair by one
(c) Compare data (d) Decrement register pair by one
6. .......................... operations alter the sequence of program execution either conditionally or
unconditionally.
(a) Logical (b) Arithmetic
(c) Branch (d) None
7. JMP is a conditional branching instruction.

(a) True (b) False
8. EI is used to enable interrupt system.
(a) True (b) False

9. .......................... instruction use to move content of H & L to Stack Pointer.
(a) PUSH (b) XTHL
(c) POP (d) SPHL

10. .......................... instruction use to exchange top of stack with H & L.
(a) PUSH (b) XTHL
(c) POP (d) SPHL

9.11 Review Questions

1. What is an instruction?
2. What is the function of the accumulator?
3. Give the functional categories of 8085 microinstructions.

4. Define Opcode and operand.
5. Define the types of branching operations.
6. Define two-byte instruction with one example.

7. Write instructions to load the hexadecimal numbers 65H in register C, and 92h in the
accumulator A .Display the number 65H at PORT0 and 92H at PORT1.
8. How is the instruction set classified?

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