FPUs

An FPU, or floating point unit, is a component of a computer's processor layout dedicated to performing arithmetic on floating point numbers. FPUs can be integrated into the central processing unit as a specialized execution unit or provided as a separate coprocessor. They are designed to handle the wide dynamic range and precision requirements of floating point calculations more efficiently than general integer arithmetic units.

Historically, floating point support often began as a separate coprocessor, such as the Intel 8087 for the x86 family, connected to a host CPU. Over time, FPUs were integrated into mainstream CPUs, with high-performance SIMD extensions later enabling vector floating point computations. Modern architectures typically embed both scalar and vector floating point hardware in a single die.

Operations and precision: FPUs implement a suite of floating point operations, including addition, subtraction, multiplication, division, and square root, along with transcendental functions in many implementations. They typically support standard precisions defined by IEEE 754, such as single precision (32-bit) and double precision (64-bit); some CPUs also support extended precision or half precision on specialized devices.

Performance characteristics: FPUs use pipelining, parallel execution, and, in many systems, SIMD or vector units to increase throughput. Latency and throughput depend on the instruction, data path width, and clock speed, with full throughput achieved when many independent operations are available.

Applications and context: Floating point hardware is essential for scientific computing, engineering simulations, computer graphics, and digital signal processing. In modern systems, FPUs are complemented by GPU-based floating point units and dedicated accelerators for large-scale or highly parallel workloads. The IEEE 754 standard provides a consistent model for rounding, exception handling, and representation.