Weitek WTL 3167 co-processor family

Weitek 3167 is a high-performance Floating Point Unit for Intel 80386 family of microprocessors. The 3167 co-processor was packaged in 121-pin ceramic PGA package and required a separate, so called Enhanced Math Coprocessor (EMC) socket to be present on the motherboard. The 3167 used different method of communication with main processor. All 80387-compatible co-processors used I/O ports to talk to main CPU. The 3167 co-processor worked like memory-mapped peripheral device - to provide instruction opcodes and data to the FPU and to get the results the main CPU could write to or read from memory assigned to the FPU. 3167 instruction set was different from Intel 80387 instruction set, therefore all applications compiled for 387 FPU didn't work with the 3167 co-processor. To take advantage of the performance offered by the 3167, the applications had to be re-compiled using a compiler which supported Weitek co-processor. Applications, re-compiled for Weitek FPU did work faster than with any other 80387 co-processor, especially when the applications used single-precision floating point numbers.