Hiding Data Cache Latency with Load Address Prediction

Toshinori SATO  Hiroshige FUJII  Seigo SUZUKI  

Publication
IEICE TRANSACTIONS on Information and Systems   Vol.E79-D   No.11   pp.1523-1532
Publication Date: 1996/11/25
Online ISSN: 
DOI: 
Print ISSN: 0916-8532
Type of Manuscript: PAPER
Category: Computer Systems
Keyword: 
RISC,  cache memory,  load-use hazard,  load latency,  address prediction,  

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Summary: 
A new prediction method for the effective address is presented. This method works with the buffer named the address prediction buffer, and allows the data cache to be accessed speculatively. As a consequence of the trend toward increasing clock frequency, the internal cache is no longer able to fill the speed gap between the processor and the external memory, and the data cache latency degrades the processor performance. In order to hide this latency, the prediction method is proposed. By this method, the load address is predicted, and the data is fetched earlier than the memory access stage. In the case that the prediction is correct, the latency is hidden. Even if the prediction is incorrect, the performance is not degraded by any miss penalties. We have found that the prediction accuracy is 81.9% on average, and thus the performance is improved by 6.6% on average and a maximum of 12.1% for the integer programs.