Contemporary microprocessor cores employ out-of-order execution in order to boost performance. One of the artifacts of the out-of-order execution is the Content Addressable Memory (CAM) cells that allow comparison of the incoming data with the stored value. Many components use these cells inside the processor such as the Issue Queue (IQ), which holds the instructions until their source operands are ready. These processor components receive lookup data each cycle and dissipate significant energy for the comparison operation.In this paper we propose a methodology to remove the capacitive load from the lookup buses and reduce the complexity of the comparison circuitry inside the CAM logic. For demonstration purposes we show the design of a new implementation of the IQ that allows the designers to transfer the complexity to the frontend stages of the processor. Our design reduces the dynamic energy dissipation of the CAM array inside the issue queue 15% with virtually no impact on performance.
Özetçe-Sayısal filtreler impals cevaplarına göre finite impulse response (FIR) ve infinite impulse response (IIR) olarak ikiye ayrılmaktadırlar. FIR filtreler çıkış sinyalinin sadece giriş sinyaline bağlı olması sebebiyle özyinelemesiz (non-recursive), IIR filtreler ise çıkış sinyalinin hem giriş hem de çıkış sinyaline bağlı olması sebebiyle özyinelemeli (recursive) olarak isimlendirilirler. Genellikle gereksinimleri verilen bir sayısal filtre FIR veya IIR olarak tasarlanabilme özelliğine sahip olsa da bu filtrelerin donanım üzerinde gerçekleştirilmelerinde farklı yaklaşımlar ve problemler ortaya çıkmaktadır. Bu çalışmada FIR ve IIR filtre tasarımlarının FPGA üzerinde gerçekleştirilirken ortaya çıkan problemler incelenmiş, donanım maliyeti ve başarım analizleri yapılarak iki tasarım metodunun karşılaştırması yapılmıştır.
Anahtar Kelimeler -FIR filtre; IIR filtre; FPGA.Abstract-Digital filters are classified into two types: Finite impulse response (FIR) and infinite impulse response (IIR) filters according to their impulse response types. FIR filters are called as non-recursive filters since the output signal is dependent only on the input signal; whereas, IIR filters are called as recursive filters since the output signal is dependent both on the input and output signals. Although for given specifications, usually both FIR and IIR filter designs can be used, different approaches and problems arise for implementation of these methods on hardware. In this work, the problems which occurred during FPGA implementation of FIR and IIR filters are examined and the comparison of the two design methods is done by analyzing the hardware cost and performance.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.