Module 1 Flashcards
What are the two main functions of the Processing Unit
1) fetch an instruction
2) execute an instruction
What is the function of a control unit?
- For each operation a unique operation code (op code)
- hardware accepts the code and issues the control signals
What is the Processing Unit made up of
1) The Control Unit
2) The Arithmetic and Logic Unit
What is the Fetch Cycle?
- Program Counter (pc) holds address of next instruction to fetch
- Processor fetches instruction from memory location pointed to by PC
- Increment PC
- Instruction loaded into Instruction Register (IR)
- Processor interprets instruction and performs required actions
What is a program?
- A sequence of
- for each step, an arithmetic or logical operation
- for each operation a different set of control signals is needed
What is the Execute?
- Processor - memory
•data transfer between CPU and Main memory - Processor I/O
• data transfer between CPU and I/O module - Data Processing
• Some arithmetic or logical operation on data - Control
• alteration of sequence of operations.
What is the Instruction Cycle of Operations
- Fetch instruction (FI)
- Decode instruction (DI)
- Calculate operands (CO)
- Fetch operands (FO)
- Execute Instruction (EI)
- Write operation (WO)
What can change the Normal Flow of control of a program
1) an exception
2) an interrupt
What are the subsystems of the Processor
1) Registers
2) Arithmetic Logic Unit
3) Control Unit
What is a Register
Registers are temporary storage units within a processor
How many Registers are found in a processor
Most have 4
What are the four Registers?
1) Program Counter
2) Instruction Register
3) Memory Address Register
4) Memory Buffer Register
What does the Program Counter do
Contains the memory address of the instruction currently being executed
What does the Arithmetic logic Unit do?
This is the subsystem that does the arithmetic.
What are the building blocks of a system?
1) Inputs
2) Process
3) Outputs
