Robert -
Far be it from me to claim to be a patent expert. However, there is a patent that Intel holds, commonly referred to as "The Crawford Patent" - in honor of John Crawaford, one of Intel's long time and leading x86 architects, that applies to the way x86 devices keep track of some basic housekeeping functions using external memory.
The concept is so fundamental to the way the 486/Pentium, etc. operate, that "almost" all implementations of an x86 processor on a motherboard with standard memory must use this technique. In other words, it is very broad and very generic.
Cyrix's and AMD's architectures implement the memory/housekeeping. To the best of my recollection, Cyrix is "covered" because their chips are made by authorized cross-licensees of Intel (IBM, SGS-Thompson). AMD and Intel reached an agreement last year giving AMD certain rights to Intel's patents for all existing (<1995 including the K5) AMD chips.
The cross licenses have expiration limits which may be significant to Cyrix in the long term. However, a fully informed legal expert should be consulted if you need a detailed opinion.
The legal hassles you refer to were between Texas Instruments and Cyrix. TI was an early foundry for CYRIX (TI is also an Intel cross-licensee). However, their relationship was not just "pure" foundry. TI was granted rights to Cyrix designs in return for a specified committed Fab capacity - i.e., wafers and functional die.
Somehwhere down the line of this cozy Texas relationship, something went wrong with the TI supply "Chuck Wagon". Cyrix could not get enough wafers and/or functional die and their delivery of x86 devices to customers suffered. They were also using SGS-Thompson at the time.
Subsequently, Cyrix turned to IBM for a similar foundry/design relationship and turned around and sued Texas Instruments for being a bad hombre. I'm sure the words "breach of contract" were uttered during this Lone Star Shoot-out.
That legal dispute lasted a few years, made some lawyers richer than they already were, and was settled about 18 months ago.
Paul |
