coprocessor

A coprocessor is a separate processor designed to augment the capabilities of a computer's central processing unit (CPU) by handling specialized tasks more efficiently than the general-purpose core. Coprocessors may have their own control logic and memory or share system resources with the CPU. They are typically invoked to perform operations that are compute-intensive or require specialized instruction sets, such as floating-point arithmetic, graphics processing, signal processing, or cryptography.

Historically, coprocessors were common in early microprocessors. For example, the Intel 8087 math coprocessor worked with the 8086/8088 to perform floating-point calculations, while separate 80387 served with the 80386. Over time these functions were integrated into CPUs, and the explicit coprocessor role diminished in some families, though the concept persists in modern designs as dedicated accelerators or coprocessors.

Common types include floating-point coprocessors, math coprocessors, graphics or video coprocessors, and signal-processing coprocessors. In contemporary computing, many devices use graphics processing units (GPUs) or digital signal processors (DSPs) as coprocessors to offload heavy workloads from the CPU. System-on-a-chip designs also embed multiple processing elements that act as coprocessors for machine learning, encryption, or multimedia tasks.

Compared with a general-purpose CPU, a coprocessor can offer higher throughput for its specialty tasks or operate more efficiently with lower power usage. Communication between the CPU and coprocessor involves a defined interface and shared or mirrored memory, and software often needs specific routines or compiler support to exploit the coprocessor. See also CPU, GPU, FPU, DSP, accelerator.