The author used high-resolution die photography to extract the microcode ROM from an NEC V20 CPU, enabling cycle-accurate emulation in the MartyPC emulator. The photomosaic at 5.6 Gigapixels revealed the microcode ROM array of 29,928 bits organized as 258x116, with 1032 expected microcode words.
Background
The NEC V20 was a popular second-source clone of Intel's 8088 CPU used in early IBM PC compatibles. Accurate emulation of vintage CPUs requires detailed knowledge of their microarchitecture, which can be obtained through die photography and microcode extraction.
- Source
- Lobsters
- Published
- Sep 10, 2026 at 06:44 PM
- Score
- 6.0 / 10