18 Questions
What is the purpose of immediate addressing mode?
Transfer the operand given in the instruction to the destination register or memory location
In Memory Direct Addressing, what does the instruction 'LDA 850FH' do?
Loads the content of memory address 850FH into the accumulator
What does Register Direct Addressing involve?
Moving a copy of a byte or word from source register to destination
Which type of addressing mode copies the content of one register to another?
Register Direct Addressing
What is the main function of machine control operations in microprocessor?
Control execution of other instructions and operations like interrupt, halt etc.
In addressing modes, what does Immediate Addressing mode primarily focus on?
Directly transferring an operand given in the instruction to destination register or memory location
What does the CY flag indicate when set to 1?
Carry
Which flag indicates that the result in the accumulator contains an even number of 1s?
P flag
What is the function of the Stack Pointer register?
Points to the memory location in R/W memory
In 2’s complement representation, what does a 1 in bit D7 of the accumulator indicate?
Negative number
Which register deals with sequencing the execution of instructions?
Program Counter
When is the AC flag set to 1?
When a carry result passes from bit D3 to bit D4
What type of operations do 8085 microprocessor instructions classified based on functionality include?
Data transfer, Arithmetic, Logical, Branching
Which type of operation involves copying data from a source to a destination without altering the source content?
Data transfer operations
In 8085 microprocessor, which operation can perform functions like AND, OR, and EXOR?
Logical operations
Which group of instructions in 8085 microprocessor can be used to transfer program sequence from one memory location to another conditionally or unconditionally?
Branching operations
What type of microprocessor operation utilizes the accumulator for storing one of the operands and the result?
Arithmetic operations
Which group of instructions in 8085 microprocessor involves copying data from one register to another without modifying the source register?
Data transfer operations
Study Notes
Machine Control Operations
- Instructions in this group control execution of other instructions and operations like interrupt, halt, etc.
Instruction Set Classification
- Classified based on length:
- One-byte instructions: machine code is one byte
- Two-byte instructions: machine code is two bytes
- Three-byte instructions: machine code is three bytes
- Classified based on addressing modes:
- Immediate Addressing: operand is part of the instruction and stored in the register mentioned in the instruction
- Memory Direct Addressing: moves data between a memory location and register
- Register Direct Addressing: transfers a copy of a byte or word from source register to destination
Addressing Modes
- Immediate Addressing:
- operand is a part of the instruction
- example: MVI A, 9AH
- Memory Direct Addressing:
- moves data between a memory location and register
- example: LDA 850FH
- Register Direct Addressing:
- transfers a copy of a byte or word from source register to destination
- example: MOV B, C
Flags and Registers
- Accumulator (A):
- 8-bit register, part of ALU
- stores 8-bit data for arithmetic and logical operations
- result of operation is stored in it
- Flags:
- CY (Carry flag): set to 1 if result is larger than 8-bit
- Z (Zero flag): set to 1 if result is zero
- S (Sign flag): a copy of bit D7 of the accumulator
- AC (Auxiliary Carry flag): set to 1 when a carry result from bit D3 and passes to bit D4
- P (Parity flag): set to 1 when the result in accumulator contains even number of 1s
- Program Counter (PC):
- 16-bit register
- deals with sequencing the execution of instructions
- points to memory address from which next byte is to be fetched
- Stack Pointer (SP):
- 16-bit register
- used as a memory pointer
- points to the memory location in R/W memory, called Stack
Bus Organization of 8085
- Microprocessor performs four operations:
- Memory Read: reads data from memory
- Memory Write: writes data into memory
- I/O Read: accepts data from input device
Instruction Set
- A group of instructions that a microprocessor supports
- Classified based on functionality:
- Data transfer operations
- Arithmetic operations
- Logical operations
- Branching operations
Explore the classification of MICROPROCESSOR 8085 instruction set based on functionality, length, and operand addressing. Learn about the different types of instructions supported by a microprocessor and how they are represented in machine code and mnemonics.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
