Chapter 5. System Software

Question 1

What is assembly language?

Answer 1

• A low-level programming language that is closer to machine code.
• Uses mnemonics to represent machine instructions.

Question 2

What is the purpose of an assembler?

Answer 2

• Translates assembly language code into machine code that the CPU can execute.
• Converts mnemonics into binary instructions.

Question 3

What are mnemonics in assembly language?

Answer 3

• Human-readable representations of machine instructions.
• Examples: ADD (addition), SUB (subtraction), MOV (move data).

Question 4

What is an opcode in assembly language?

Answer 4

• The part of a machine instruction that specifies the operation to be performed.
• Example: ADD in the instruction ADD R1, R2.

Question 5

What are operands in assembly language?

Answer 5

• The part of a machine instruction that specifies the data or memory locations involved.
• Example: R1 and R2 in the instruction ADD R1, R2.

Question 6

What is the difference between immediate addressing and direct addressing?

Answer 6

• Immediate addressing: The operand is a constant value within the instruction.
• Direct addressing: The operand is the address of the data in memory.

Question 7

What is the function of the Instruction Set?

Answer 7

• A set of instructions that a CPU can execute.
• Defines the operations, addressing modes, and data types supported.

Question 8

What is the difference between a label and a comment in assembly language?

Answer 8

• Label: A symbolic name for a memory address.
• Comment: An annotation in the code for clarification, not executed by the assembler.

Question 9

What are the advantages of using assembly language?

Answer 9

• Provides greater control over hardware.
• Efficient in terms of execution speed and memory usage.

Question 10

What are the disadvantages of using assembly language?

Answer 10

• Difficult to learn and write.
• Less portable compared to high-level languages.

Question 11

What is the purpose of a register in assembly language?

Answer 11

• Used to store data temporarily during program execution.
• Faster to access than memory locations.

Question 12

What is the role of the Program Counter (PC) in assembly language?

Answer 12

• Holds the address of the next instruction to be executed.
• Automatically incremented after each instruction fetch.

Question 13

What are addressing modes in assembly language?

Answer 13

• Ways of specifying data or memory locations in instructions.
• Examples: Immediate, Direct, Indirect, Indexed.

Question 14

What is the difference between a high-level language and assembly language?

Answer 14

• High-level language: Easier to write and understand, more abstract.
• Assembly language: Closer to machine code, provides more control over hardware.

Question 15

What is a macro in assembly language?

Answer 15

• A sequence of instructions that can be reused in the code.
• Defined once and used multiple times to save repetition.

Question 16

What is a subroutine in assembly language?

Answer 16

• A set of instructions designed to perform a specific task.
• Can be called from multiple places in the program.

Question 17

What is the purpose of the Stack Pointer (SP) in assembly language?

Answer 17

• Points to the top of the stack in memory.
• Used to manage function calls and local variables.

Question 18

What are the typical uses of assembly language?

Answer 18

• Writing firmware or operating systems.
• Performance-critical applications where low-level hardware control is needed.

Question 19

What is the function of the Accumulator (ACC) in assembly language?

Answer 19

• A register used to store intermediate results of arithmetic and logic operations.
• Commonly used in older CPU architectures.

Question 20

What is the role of the Linker in assembly language programming?

Answer 20

• Combines multiple object files into a single executable.
• Resolves references between different modules or libraries.