The Intel 80387SX (387SX or i387SX) is the math coprocessor, also called an FPU, for the Intel 80386SX microprocessor. Introduced in 1987, it was used to perform floating-point arithmetic operations directly in hardware. The coprocessor was designed only to work with the 386SX, rather than the standard 386DX. This was because the original 80387 could not communicate with the altered 16 bit data bus of the 386SX, which was modified from the original 386DX's 32 bit data bus. The 387SX uses a 68- Wi...
