The article details how the Intel 80386 CPU implemented backwards compatibility with 8- and 16-bit software. It explains the use of SRAM for register storage, a triple-ported register file, and a 'shuffle' network to handle different bit-width reads and writes, including interleaving the bottom 16 bits of the registers.
Ken Shirriff, a reverse engineer and vintage electronics enthusiast, discovered the root cause of Intel's infamous Pentium FDIV bug in the silicon itself, identifying the PLA block responsible for a half-billion-dollar recall due to a mathematical error in constructing the table for division algorithm.
