Reverse engineering the barrel shifter circuit on the Intel 386 processor die (righto.com) The Intel 386 processor (1985) was a large step from the 286 processor, moving x86 to a 32-bit architecture. The 386 also dramatically improved the performance of shift and rotate operations by adding a “barrel shifter”, a circuit that can shift by multiple bits in one step. The die photo below shows the 386’s barrel shifter, highlighted in the lower left and taking up a substantial part of the die.