Pipelines and it types and purposes, interrupt and its types

a) A pipelining is a process of collecting instructions from the processor through the pipeline and it allows store and executes the instructions in order which is called pipelining.

b) The three types of hazards are

1) Structural Hazards

2) Data Hazards

3) Control Hazards

Structural Hazards: These hazards appear by resource problems when the hardware of the system can't support the possible combination of the instruction in overlapped execution.

Eg: It occurs when the same resource is used by two or more instructions which is in pipeline.

Data Hazards:  It appears when the execution of the instruction depends on the previously executed instruction.

Eg : These Hazards appear in reading at processor RAW).

Control Hazards : This hazards appears from pipelining of branches and the other instructions which changes the PC.

c) In the 8086 processor, When the interrupt occurs the processor exceutes the current instruction completely and then executes the Interrupt service routine which is the program that guides the processor what to perform when the interrupt occurs. After execution of an interrupt the control returns back to main routine.

d) The use of 8259 is it combines multi interrupt inputs into single interrupt output.

The purposes are :

• It can be used to implement 8 level interrupt systems because it's an LSI chip.
• It can find the interrupting device.
• It can be operated in different priority modes like fixed or rotating priority.
• It can use in buffered mode.

e) The types of interrupts are :

1. Maskable interrupt
2. Non Maskable interrupt

Maskable Interrupt: These are the hardware interrupts where the processor delays the execution when the highest priority interrupt arrives.

Non-Maskable Interrupt: These are the hardware interrupts that can't be delayed and should process immediately.