Data Pipeline
The part of a cache pipeline that reads, aligns, and returns the actual data stored in cache lines.
Detailed Explanation
While the tag pipeline decides whether the access hits, the data pipeline fetches the bytes or words that the processor actually needs. Once the indexed set is known, the cache reads candidate data words from the selected way, extracts the requested subword, and aligns it for the load path. Stores may also update only part of a cache line using byte enables and write masks.
Designers often treat the data path and tag path separately because they have different timing and structural concerns. The data RAM can be wide and physically large, while the tag RAM is narrower but more control-sensitive. Keeping those paths distinct makes it easier to optimize access energy, critical path, and hit latency.