The i486 CPU: executing instructions in one clock cycle
John H. Crawford · IEEE Micro · 1990
The author discusses the design goals of the i486 development program, which were to ensure binary compatibility with the 386 microprocessor and the 387 math coprocessor, increase performance by two to three times over a 386/387 processor system at the same clock rate, and extend the IBM PC standard architecture of the 386 CPU with features suitable for minicomputers. A cache integrated into the instruction pipeline lets this 386-compatible processor achieve minicomputer performance levels. The design and performance of the on-chip cache and the instruction pipeline are examined in detail.>