Chapter One Introduction to Pipelined

Processors

Principle of Designing Pipeline Processors

(Design Problems of Pipeline Processors)

Internal Data Forwarding and Register Tagging

Internal Forwarding and Register Tagging

• Internal Forwarding: It is replacing unnecessary memory accesses by register-to-register transfers.

• Register Tagging: It is the use of tagged registers for exploiting concurrent activities among multiple ALUs.

Internal Forwarding

• Memory access is slower than register-to-register operations.

• Performance can be enhanced by eliminating unnecessary memory accesses

Internal Forwarding

• This concept can be explored in 3 directions:1.Store – Load Forwarding2.Load – Load Forwarding3.Store – Store Forwarding

Store – Load Forwarding

Load – Load Forwarding

Store – Store Forwarding

Example

EXAMPLE

Example

EXAMPLE