The document provides an introduction to microprocessors, detailing their definition, key characteristics, and fundamental components, such as registers and the Arithmetic Logic Unit (ALU). It also explains the instruction set, execution cycle, and various memory addressing modes, emphasizing the programmability and general-purpose nature of modern microprocessors. Additionally, the document touches upon assembly language as a low-level programming interface to hardware, explaining its role in understanding computer operations.

1. Lecture1
Introduction to Microprocessors
By
Dr. Mohammed Y.M Alnaham

2. A microprocessor
• A microprocessor is a central processing unit
(CPU) implemented on a single integrated
circuit (IC) chip.
• It is the essential component of a computer
that performs arithmetic and logical
operations, controls the computer's operation,
and manages the flow of information to and
from other components of the computer
system.

3. The key characteristics of a microprocessor
• 1. Integration: A microprocessor integrates multiple
electronic components, including the CPU, memory, and
input/output interfaces, onto a single silicon chip.
• 2. Programmability: Microprocessors are programmable
devices, which means they can be instructed to perform
a wide range of tasks by executing software programs.
• 3. General-purpose: Modern microprocessors are
designed to be general-purpose, allowing them to be
used in a variety of applications, from personal
computers to embedded systems.

4. • 4. Performance: Microprocessor performance is
measured in terms of clock speed (frequency),
number of cores, and other architectural features
that enable faster processing of instructions.
• 5. Power efficiency: Advances in microprocessor
design and manufacturing have led to
increasingly power-efficient microprocessors,
making them suitable for use in portable and
battery-powered devices.

5. • Microprocessors are the backbone of
modern computing and are found in
a wide range of devices, including
personal computers, smartphones,
tablets, servers, gaming consoles,
and a vast array of embedded
systems like industrial machinery,
household appliances, and
automotive electronics.

6. Introduction to Computer Architecture

7. Primary registers of a microprocessor in Von
Neumann architecture
• 1. Program Counter (PC): The program counter
stores the memory address of the next
instruction to be fetched and executed. It is used
to keep track of the current position in the
program.
• 2. Accumulator (ACC): The accumulator is a
central register that holds the results of
arithmetic and logic operations. It is used to store
intermediate results during computational tasks.

8. • 3. Memory Address Register (MAR): The memory
address register holds the memory address from
which data is to be read or to which data is to be
written.
• 4. Memory Data Register (MDR): The memory data
register holds the data that is to be written to or
read from memory.

9. Microprocessor Fundamentals
• Instruction Set,
• Registers,
• Memory Addressing Modes,
• ALU

10. Instruction Set
The instruction set of a microprocessor refers to the
collection of machine-level instructions that the
processor can execute.
• 1. Instruction Format:
- Opcode: Specifies the operation to be performed
(e.g., add, subtract, load, store)
- Operands: Specifies the data or addresses involved in
the operation
 - Addressing Modes: Specify how the operands are
accessed (e.g., immediate, direct, indirect)

11. Instruction Set
• 2. Instruction Types:
 - Data Transfer Instructions: Load, store, move data
between registers, memory, and I/O
 - Arithmetic and Logical Instructions: Add, subtract,
multiply, divide, logical operations (AND, OR, XOR, NOT)
 - Control Transfer Instructions: Conditional and
unconditional jumps, calls, returns
 - Comparison Instructions: Compare values and set
flags - Interrupt Instructions: Enable, disable, and
handle interrupts

12. Instruction Set
• 3. Instruction Execution Cycle:
 - Fetch: Retrieve the instruction from memory
- Decode: Interpret the instruction and
determine the operation to be performed
 - Execute: Perform the specified operation
 - Write Back: Store the result of the
operation

13. Instruction Set
• 4. Addressing Modes:
 - Immediate: The operand is a constant value
specified in the instruction
- Direct: The operand is located at a specific
memory address
- Indirect: The operand's address is stored in a
register
- Indexed: The operand's address is calculated by
adding an index value to a base address

14. Instruction Set
• 5. Microarchitecture:
- Pipelining: Allows multiple instructions to be
executed concurrently, improving performance
 - Superscalar: Allows multiple instructions to be
executed in parallel, further improving
performance
 - RISC vs. CISC: Reduced Instruction Set
Computer (RISC) vs. Complex Instruction Set
Computer (CISC) architectures

15. Memory addressing modes
In a microprocessor there are the different ways in which the
processor can access memory locations to retrieve or store data.
1. Immediate Addressing:
- The operand is a constant value directly specified in the
instruction.
- Example: MOV AX, 0x12342.
2. Direct Addressing:
- The operand's memory address is directly specified in the
instruction.
- Example: MOV AX, [0x1000]

16. Memory addressing modes
• 3. Indirect Addressing:
 - The operand's memory address is stored in
a register. - Example: MOV AX, [BX]
• 4. Indexed Addressing:
 - The operand's memory address is calculated
by adding an index value (in a register) to a
base address. - Example: MOV AX, [BX + SI]

17. Memory addressing modes
• 5. Base-Indexed with Displacement Addressing:
- The operand's memory address is calculated by
adding a base register, an index register, and a
constant displacement value. - Example: MOV AX,
[BX + SI + 0x10]
• 6. Relative Addressing:
- The operand's memory address is calculated by
adding a signed offset to the current instruction's
address (program counter). - Example: JMP [PC +
0x100].

18. Arithmetic & Logic Unit (ALU)
ALU is a fundamental component in the central
processing unit (CPU) of a computer. It is
responsible for performing arithmetic and
logical operations on data.

19. ALU
The main functions of an ALU include:
• 1. Arithmetic Operations:
 - Addition
 - Subtraction
 - Multiplication
 - Division

20. ALU
• 2. Logical Operations:
 - AND
- OR
 - NOT
- XOR
- Shift operations (left/right shift)

21. Introduction to Assembly Language
Assembly language is a low-level programming language
that provides a direct interface to a computer's
hardware.
• Machine Code and Instruction Set
• Each instruction in the machine code has a
corresponding mnemonic (a short, meaningful
abbreviation) in the assembly language.
• An assembler is a program that translates assembly
language code into machine code that the CPU can
execute.

22. Introduction to Assembly Language
• Assembly language programs often need to
work with registers directly
• 5. Assembly language programs need to be
able to access memory locations, both for
reading and writing data. This is done through
memory addressing schemes, which are
specified in the assembly language.

23. Introduction to Assembly Language
• Each assembly language has its own syntax and
structure, which can vary depending on the
specific CPU architecture. However, most
assembly languages share common elements,
such as instructions, operands, and labels
• Assembly help us to understand how
computers work at a fundamental level and
understanding how high-level programming
languages are implemented.

24. •What instruction
execution cycle mean?
•Define the assembler?

25. Power efficiency in microprossesor