CompTIA A+ Certification All-in-One Exam Guide

part, the arithmetic logic unit (ALU) (or integer unit), handles integer math:
basic math for numbers with no decimal point. A perfect example of integer
math is 2 + 3 = 5. The typical CPU spends most of its work doing integer
math. CPUs also have special circuitry to handle complex numbers, called the
floating point unit (FPU). With a single pipeline, only the ALU or the FPU
worked at any execution stage. Worse yet, floating point calculation often
took many, many clock cycles to execute, forcing the CPU to stall the
pipeline until the FPU finished executing the complex command (see Figure
3-25). Current CPUs offer multiple pipelines to keep the processing going
(see Figure 3-26).
Figure 3-25 Bored integer unit