Question

Hello, I am studying and I am a bit confused about registers. There are segments registers, data registers, pointer registers, index registers. But I do not really understand where these are found. Are they found in 8086 architecture? For instance if I ask what type of registers are found in 8086 architecture what will be the answer? All of these or only segment registers?

Answer 1

Total Number of Registers in 8086 are Eight which are AX,BX,CX,DX,SI,DI,SP,DP

The Segment resisters and status register works together with general purpose register.The segment register are used to accessing the desired memory value.

In 8086 Microprocessor we can say their are four type of registers and all registers are of length 16 bit which are categorized as follows :

1.Generel Purpose Register

These register are use to store the data temporarily there are 8 registers in it but out of it 4 are mandatory general purpose register of 16 bit length each which are further divided into two subpart of 8 bit .

a.AX - It is accumulator used for athematic and logical operation

b.BX- It is Base register used to store the value of offset

c.CX- It is counter register used for looping and rotation

d.DX -It is data register used for multiplication of input and output port addressing

2.Segment Register.

This register are used to store the starting address of the data to get location of data it are very useful.There are 4 types of segment register in it which are of length 16bit.

a.Code segment register

It can be used by Microprocessor compiler only its segment contents can be modified by the user

b.Data segment register

It can be modified by user as per it's requirements

c.Stack segment register

It is used to store information about the memory segment and it's operations are push and pop

d.Extra segment register

If their are insufficient space in any of above segment compile of Microprocessor use this register

3.Pointer and Index Register

it stores the address or the memory location

a.Instruction pointer(IP)

It stores the address of the instruction which is going to be executed

b.Base pointer(BP)

It store the base address of the parameter in memory location

c.Stack pointer(SP)

It points towards the top parameter/element on the stack

d.Source Index Register(SR)

It's is used in string related operation and also stores the source address

e.Destination Index Register(DR)

It stores the destination address of element and also stores the string related operations.

4.Flag or Status Register

This tells us the status of the athematic and logical operation of an processor if flag is 1 then operation is successful and the flag is set to 1 ,if operation is not successful then flag is 0 which is going to be reset