Important Definitions Components of a Digital Computer Computer Registers Buses Instructions Stack Organized CPU Internal Working of CPU

1. Computer
Architecture
Syed Zaid Irshad

2. Outline
– Important Definitions
– Components of a Digital Computer
– Computer Registers
– Buses
– Instructions
– Stack Organized CPU
– Internal Working of CPU

3. Important Definitions
– Computer Organization
– How computer components works and how they work together with other
components
– Computer Design
– Hardware design of computer
– Computer Architecture
– It is concerned with the structure and behaviour of the computer as seen by the user

4. Components of a Digital
Computer
– Components of a Digital Computer can be classified into four which are
following:
– Input
– Output
– CPU
– Memory

5. Computer Registers
– General purpose Register
– Store Data Temporary
– Accumulator
– Store Data Temporary for Arithmetic/Logical Operations
– Status Register
– Carry, Zero, Sign, Parity flags, 1-bit
– Memory Buffer Register
– Store Data which is being used

6. Computer Registers
– Memory Address Register
– Address of Data in MBR
– Instruction Register
– Instruction that is being used on Data
– Program Counter
– Store order of Execution
– Stack Pointer
– Set of Memory Locations

7. Buses
– There are three types of Buses called:
– Address Bus
– Address of Memory location travel on these paths
– Data Bus
– Required or Updated Data travel on these paths
– Control Bus
– It controls the reading and Writing of the Data

8. Instructions
– It is an order for a computer to perform a certain operations.
– A typical instruction has two parts:
– Operation Code
– Means which of arithmetic or logical operation is required
– Address
– On which data or set of data will be used for the operation

9. Instructions
– Following are the types of Instruction Format:
– Three-Address Instruction
– Operation Code, Two Operand Address, One Result Address
– Two-Address Instruction
– Operation Code, One Operand Address, One Result Address
– One-Address Instruction
– Operation Code, One Operand Address
– Zero-Address Instruction
– Operation Code

10. Stack Organized CPU
– Stack store data in such manner that the last entry get to use first in order to
retrieve the very first data.
– Stack has two kind of Operation, PUSH & POP, Push insert the data into stack
whereas Pop retrieve it.
– Polish Notation is used in Stacks to perform the operation of data.
– There are two types of Polish Notations:
– Prefix (Polish) Notation
– Postfix (Reverse Polish) Notation

11. Stack Organized CPU
– Infix Notation:
𝐴 + 𝐵, 𝐶 − 𝐷, 𝐸 ∗ 𝐹,
𝐺
𝐻
, 𝐴 + 𝐵 ∗ 𝐶, 𝐴 + (𝐵 ∗ 𝐶)
– Prefix Notation:
+𝐴𝐵, −𝐶𝐷,∗ 𝐸𝐹,/𝐺𝐻, +𝐴𝐵 ∗ 𝐶,∗ 𝐵𝐶 + 𝐴
– Postfix Notation:
𝐴𝐵+, 𝐶𝐷−, 𝐸𝐹 ∗, 𝐺𝐻/, 𝐴𝐵 + 𝐶 ∗, 𝐵𝐶 ∗ 𝐴 +

12. Stack Organized CPU
– Example:
4 ∗
3
1
+ 5
– Postfix Expression:
4 3 ∗ 1/5 +
4
Stage 1
3
4
Stage 2
12
Stage 3
1
12
Stage 4
12
Stage 5
5
12
Stage 6
17
Stage 7

13. Internal Working of CPU
– CPU is the unit that take the input, perform some operations and provide the
store the output in memory.
– This whole process is done in mainly two steps:
– Fetch
– Execute
– Which are known as Instruction Cycle.

14. Internal Working of CPU
– In Fetching Process following registers are used:
– Instruction Register
– Memory Buffer Register
– Program Counter
– Memory Address Register
– In Execution Process:
– Instruction Register holds
– Operation code
– Address of Operand