The Intel 80387 ('387') was the math coprocessor for the Intel 80386 series of microprocessors, and the first Intel coprocessor to implement the IEEE 754 standard in every detail. It was used to perform floating point arithmetic operations directly in hardware. The 387 was compatible only with the standard 386 chip; the cut down 386SX had its own coprocessor, the Intel 80387SX, that could work with the SX's smaller data bus. The coprocessor was released in 1987, two years after the 386 chip was put into production.

x86 microprocessors

i387 | Intel 80387 | Intel 80387 | Intel 80387