A deep dive into the clever barrel shifter design used in the Intel 80386 processor, explaining how it efficiently performs bitwise shifts and rotations. The article details the logic behind the shifter, its construction using multiplexers, and how it contributes to the 80386's performance.
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.
