AMD 80287 floating-point unit family
While the AMD received rights to manufacture 80286 and earlier Intel processors, they didn't get rights to 80287 math co-processor due to cancellation of 1982 technical agreement between AMD and Intel. Since AMD had limited rights granted them by still active 1976 cross-license agreement between Intel and AMD, they went ahead with reverse-engineering of the 80287. Reverse-engineering and design was performed by third company - Micro Integration Corp. The end result was AMD 80C287 CMOS co-processor that used Intel microcode. In 1990 the 80C287 was ready for production, and AMD notified Intel about their plans to release the co-processor. In response, Intel sued AMD alleging that AMD infringed on copyright on the Intel 287 microcode. In 1992 court ruled that the 1976 cross-license agreement didn't cover 80287 microcode. It took two more years before in 1994 the ruling was overturned, and AMD finally received rights to sell their version of 80C287 FPU with Intel microcode.
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