Since the early 1990s, many microprocessors for desktops and servers have more than one FPU.
The modular architecture of Bulldozer microarchitecture uses a special FPU named Flex FPU, which uses simultaneous multithreading.
Where floating-point calculation hardware has not been provided, floating point calculations are done in software, which takes more processor time but which avoids the cost of the extra hardware.
For a particular computer architecture, the floating point unit instructions may be emulated by a library of software functions; this may permit the same object code to run on systems with or without floating point hardware.
In systems without any floating-point hardware, the CPU emulates it using a series of simpler fixed-point arithmetic operations that run on the integer arithmetic logic unit.
The software that lists the necessary series of operations to emulate floating-point operations is often packaged in a floating-point library.
In some cases, only the simple operations may be implemented in hardware or microcode, while the more complex operations are implemented as software.In most modern computer architectures, there is some division of floating-point operations from integer operations.This division varies significantly by architecture; some, like the Intel x86 have dedicated floating-point registers, while some take it as far as independent clocking schemes. In earlier superscalar architectures without general out-of-order execution, floating-point operations were sometimes pipelined separately from integer operations.When a CPU is executing a program that calls for a floating-point operation, there are three ways to carry it out: Some systems implemented floating point via a coprocessor rather than as an integrated unit.This could be a single integrated circuit, an entire circuit board or a cabinet.