A floating-point unit (FPU, colloquially a math coprocessor) is a part of a computer system specially designed to carry out operations on floating-point numbers. Typical operations are addition, subtraction, multiplication, division, and square root. Some FPUs can also perform various transcendental functions such as exponential or trigonometric calculations, but the accuracy can be very low, so that some systems prefer to compute these functions in software.
In general-purpose computer architectures, one or more FPUs may be integrated as execution units within the central processing unit; however, many embedded processors do not have hardware support for floating-point operations (while they increasingly have them as standard, at least 32-bit ones).
When a CPU is executing a program that calls for a floating-point operation, there are three ways to carry it out:
- A floating-point unit emulator (a floating-point library).
- Add-on FPU.
- Integrated FPU.