Intel 80287
The intel 80287 was a floating point co-processor to intel's 80286 models of single chip computer.[1][2] 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.[2]
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.
References
- ↑ Advanced Micro promotes its power-saving answers to intel 80287 in the UK, Computer Business Review, 1990-08-22. Retrieved on 2008-11-27. mirror
- ↑ 2.0 2.1 Omar Alvarado, Thomas J. Fellers, Michael W. Davidson. intel 80287: Technical Specification. Retrieved on 2008-11-27. mirror