MCL86+ Drop-in 8088 CPU Emulator

We’ve covered MicroCoreLabs’ emulation projects before, including a cycle-accurate Zilog Z80 Emulator for the TRS-80 Model III, and a drop-in that resulted in the world’s fastest Commodore 64.

Well, Ted is at it again, this time emulating the venerable Intel 8088, in his MCL86+ 8088 replacement board for the IBM PC/XT and clones.

As always, this Teensy 4.1-based project offers both cycle-accurate 4.77MHz and accelerated modes. Running the SuperSoft Diagnostic ROM with 256KB of RAM in the Teensy 4.1’s memory at 800Mhz, with 8088 cycle accuracy disabled, performance is estimated at around 10x, although the disk drives and keyboard were unable to keep up, somewhat limiting practical use. As always, source for cycle-accurate and accelerated firmware is available on GitHub, along with schematics and fabrication files for the PCB that performs voltage level shifting and adapts it to the 8088 socket. Be sure to watch below as MCL86+ takes on the emulator-crushing 8088 MPH demo!