The "TMX" prefix is the key here. In Texas Instruments nomenclature, "TMS" is a production chip, but "TMX" denotes an experimental prototype. This is a pre-production version of the TMS320C4x Floating Point DSP.
These chips were the heavy lifters of the 90s, used in everything from military radar to high-end audio processing. This specific unit features a beautiful gold lid and ceramic body, a standard for high-reliability prototypes.
