Inside the Machine

The Floating-Point Units (FPUs)

While the mass market’s demand for integer performance may not be picking up, its demand for floating-point seems insatiable. Games, 3D rendering, audio processing, and almost all other forms of multimedia- and entertainment-oriented computing applications are extremely floating-point intensive. With floating-point applications perennially driving the home PC market, it’s no wonder that the Pentium 4’s designers made their design trade-offs in favor of FP performance over integer performance.

In terms of the way they use the processor and cache, floating-point applications are in many respects the exact opposite of the integer applications described in the preceding section. For instance, the branches in floating-point ...