The Unabridged Pentium 4 IA32 Processor Genealogy

An Overview of the Pentium^® Internal Architecture

The First Superscalar IA32 Processor

Processors prior to the Pentium® had a single instruction pipeline and could only execute one instruction per clock cycle. Refer to Figure 20-1 on page 466. The Pentium® was the first IA32 processor that employed parallel execution units capable of executing multiple instructions simultaneously. The Pentium® processor had dual instruction pipelines and could therefore execute up to two instructions per clock cycle.

Figure 20-1. The P5 Internal Architecture

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The two instruction pipelines were called the “u” and the “v” pipelines and they ...