Microprocessor and Computer Architecture · Unit 2
Instruction Set and Addressing Modes
Exam-focused notes for Instruction Set and Addressing Modes (Microprocessor and Computer Architecture, BIT151): what the TU syllabus asks and how it has actually been tested, with 9 solved past questions from this unit.
What this unit covers
- Instruction format and structure
- Instruction types and classification
- Addressing modes in 8085
- Arithmetic instructions with examples
- Instruction cycle and execution time
Addressing modes in 8085
Explain different addressing modes in 8085 microprocessor.Explain any five arithmetic instructions in 8085 microprocessor with suitable example.[5+5]
(a) Addressing Modes An addressing mode refers to the way in which the operand (data) is specified in an instruction. The 8085 microprocessor supports the following addressing modes: --- - The operand (data) is directly specified in the instruction itself. ...
Full solved answer →What is Addressing Modes? Explain each with example. Explain the function and type of addressing mode with reason of instructions STA 4000H.[10]
Addressing Mode is the method by which the CPU identifies or specifies the location of the operand (data) to be used in an instruction. It defines how the processor accesses data during program execution. --- The operand (data) is directly included in the i...
Full solved answer →What is addressing mode? Explain different addressing modes in 8085 microprocessor. [5]
Addressing mode refers to the way in which the operand (data) of an instruction is specified or accessed. It defines the method used by the CPU to identify the location of the data to be operated upon. --- The 8085 microprocessor supports the following addr...
Full solved answer →Arithmetic instructions with examples
Write an assembly language program to multiply 08H and 09H, store the product in memory location 8050H and carry in 8051H using 8085 microprocessor instructions. [5]
- Multiplicand = 08H - Multiplier = 09H - Product storage address = 8050H - Carry (higher byte) storage address = 8051H The 8085 has no hardware multiply instruction, so multiplication is done by repeated addition: add the multiplicand (08H) to itself the n...
Full solved answer →Write 8085 assembly language to add two numbers located at 2030H and 2040H. Store the sum in the address 2050H. [5]
- First number is stored at memory address 2030H - Second number is stored at memory address 2040H - Store the result (sum) at memory address 2050H --- --- Step Instruction Operation ------------------------------ 1 LXI H, 2030H HL register pair points to a...
Full solved answer →Write a 8085 assembly langauge for division of two 8-bit numbers by repeated subtraction method. [5]
Division by repeated subtraction works by repeatedly subtracting the divisor from the dividend until the result becomes zero or less than the divisor. The number of times subtraction is performed gives the quotient, and the remaining value is the remainder....
Full solved answer →Instruction types and classification
Write an assembly language program to swap the content of memory location 8000H and 9000H using 8085 microprocessor instructions. [5]
To swap the contents of two memory locations, we need a temporary register to hold one value while we move the other. Steps: 1. Load the content of memory location 8000H into register A 2. Move it to register B (temporary storage) 3. Load the content of mem...
Full solved answer →What are different types of instructions available in 8085 microprocessor? Write a program to find smallest element of an array: (Assume all the necessary data and memory location).[10]
This is a conceptual + programming question. No numeric matrices given. Assumptions to be made by student: - Array base address, count location, result location, and sample data are all "assume as necessary." Chosen assumptions (standard): - Count of elemen...
Full solved answer →Instruction cycle and execution time
What is instruction cycle? If the clock frequency is 5 MHz, how much time is required to execute an instruction MVI A, 08H? [3+2]
- Clock frequency: $f = 5 \text{ MHz} = 5 \times 10^6 \text{ Hz}$ - Instruction: MVI A, 08H (8085 microprocessor) --- An instruction cycle is the total time taken by a microprocessor to fetch, decode, and execute a single instruction. It represents one comp...
Full solved answer →Make Unit 2 stick
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