Depending on whether they qualify as "software" (IMO, yes) my guess is the HDL[1] specifications for modern CPUs are tops in complexity, in lines of code if not

Depending on whether they qualify as "software" (IMO, yes) my guess is the HDL[1] specifications for modern CPUs are tops in complexity, in lines of code if not man-hours (I imagine they're mostly procedurally-generated). [1] https://en.wikipedia.org/wiki/Hardware_description_language https://en.wikipedia.org/wiki/Hardware_description_language