Pipelining

Pipelining is the process of accumulating instruction from the processor through a pipeline. It allows storing and executing instructions in an orderly process. It is also known as pipeline processing.

Before moving forward with pipelining, check these topics out to understand the concept better :

1. Memory Organization 2. Memory Mapping and Virtual Memory 3. Parallel Processing

Pipelining increases the overall instruction throughput.

In pipeline system, each segment consists of an input register followed by a combinational circuit. The register is used to hold data and combinational circuit performs operations on it. The output of combinational circuit is applied to the input register of the next segment.

Arithmetic Pipeline

Instruction Pipeline

The floating point addition and subtraction is done in 4 parts:

1. Compare the exponents. 2. Align the mantissas. 3. Add or subtract mantissas 4. Produce the result.

Registers are used for storing the intermediate results between the above operations.

In this a stream of instructions can be executed by overlapping fetch, decode and execute phases of an instruction cycle. This type of technique is used to increase the throughput of the computer system.

An instruction pipeline reads instruction from the memory while previous instructions are being executed in other segments of the pipeline. Thus we can execute multiple instructions simultaneously. The pipeline will be more efficient if the instruction cycle is divided into segments of equal duration.

The cycle time of the processor is reduced.

It increases the throughput of the system

It makes the system reliable.

The design of pipelined processor is complex and costly to manufacture.

The instruction latency is more.