Intel® Itanium® floating-point architecture

The Intel® Itanium® architecture is increasingly becoming one of the major processor architectures present in the market today. Launched in 2001, the Intel Itanium processor was followed in 2002 by the Itanium 2 processor, with increased integer and floating-point performance. Measured by the SPEC CINT2000 benchmarks, the Itanium 2 processor still trails by about 25% the Intel P4 processor in integer performance, albeit P4 runs at more than three times Itanium's clock frequency. However, its floating-point performance clearly leads in the SPEC CFP2000 charts, and its rating is about 25% higher than that of the P4 processor. While the general features of the Itanium architecture such as large register sets, predication, speculation, and support for explicit parallelism [1] have been presented in several papers, books, and mainstream college textbooks [2], its floating-point architecture has been less publicized. Two books, [3] and [4], cover well this area. The present paper focuses on the floating-point architecture of the Itanium processor family, and points out a few remarkable features suitable to be the focus of a lecture, lab session, or project in a computer architecture class.