The z386 project aims to implement the Intel 80386 processor core on an FPGA. Recent optimizations have significantly improved its performance, including the implementation of early start memory access and a reduction in branch jump cycles from 9.25 down to six through microcode refinements. These changes resulted in approximately a 39% increase in DOOM benchmark scores, though the project still falls short of original hardware speed and cannot yet boot Windows.
- Implementation of early start memory access for FPGA cores
- Optimization of store queues and branch jump timing
- Significant performance gains in gaming benchmarks
- Implementation of early start memory access for FPGA cores
- Optimization of store queues and branch jump timing
- Significant performance gains in gaming benchmarks
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.
