Intel 80287

The intel 80287 was a floating point co-processor to intel's 80286 models of single chip computer. The 80287 was introduced in 1982.

Integer arithmetic requires much less silicon real estate to implement than calculations on values that had a fractional component. Intel off-loaded the hardware to perform those instructions to a co-processor -- a support chip devoted solely to that task. Computers could be equipped with an 80286, and without an 80287. If the 80287 were present floating point instructions would be off-loaded and executed relatively quickly, by the 80287.

The intel 80287 is reported to use the same execution unit as the intel 8087.

Other chips which were lineal ancestors to the Pentium family of computer chips, the intel 80186 and the intel 80386, had a companion floating point co-processor manufactured to accompany it. Intel was to market an intel 80487. But it was not a separate chip, different from the intel 80486.