A computer Consists of

1. CPU

2. MEM

3. Extended Memory I/O

CPU

CPU consists of

1. ALU

2. Registers

The function is to control data movement through data path through data signal

Instruction Cycle

Instruction Fetch

Every instruction fetch consist of four micro words

Micro word are controlled by Control Unit Architecture

Control Unit Architecture

Control Unit Architecture consists of two type of implementations

· Firmware/ Microprogram bale

· Hardware

ASM Implementation of Controller

· ASM implantation was carried out by JK flip flop

Instruction Set

Each processor is capable of carrying out some operations, which are defined by instruction set .

An instruction can be studied in terms of

Format of Instruction (OP CODE)

DATA FORMAT

OP CODE

MOV

AND

Study Case 3

No operand Instruction

HLT //Halt

DATA FORMAT

Which format needs to be used

· Binary

· Decimal

· How to be deal with fraction

· Fixed point

· Over flow

· Negative number s

1. Lets say X is in register and Y is available in memory.

2. So we need to fetch Y from memory

3. The instruction size is 2 byte

4. The Memory is one byte long

We know the architecture of controller is

As the instruction is of two byte instruction register will be of two byte

Now lets suppose the address of memory locations are

The FETCH Sequence

PC WILL HOLD 1000

Remember

TIP To SOLVE

So we can assume that instruction would be like this

Now we will have Data fetch cycle , as now data from Y address will be fetched. Before that instruction fetch was being carried out

EXECUTE