5 ms·

I wouldn’t say “none”. Real estate in CPUs is extremely expensive.

• akira2501 3y ago
  My immediate sense is that the entire vector system easily dwarfs the 16bit system.. as I'm guessing most of the modern 16bit mode is entirely in microcode.
• userbinator 3y ago
  ...and taken up mostly by cache and vector execution units. An 8086 has 29000 transistors. A modern CPU has several billion. The amount needed to implement the 16-bit subset of the ISA is an absolutely tiny fraction of the total area.
  • FullyFunctional 3y ago
    Ah, I see you don't work in the field. A few of the cost of legacy: * exponential growth in verification space (each feature combines with all other features), * design complexity (effort that could be spent better), * area/power/cycle time overhead (all options require more ports to muxes, more wires to run, etc.) * and most importantly, opportunity costs: some optimization tricks can't be pursued because the assumptions would break for legacy code The legacy tax is real
    • userbinator 3y ago
      Ah, I see you don't work in the field. I won't give away too much of my personal history, but it suffices to say I've worked with x86 at the hardware level before. each feature combines with all other features They do, but orthogonally. effort that could be spent better Effort that has already been spent. all options require more ports to muxes, more wires to run, etc It's all ultimately split into uops anyway. some optimization tricks can't be pursued because the assumptions would break for legacy code What assumptions in particular?
      • FullyFunctional 3y ago
        Well, everything I said was true but I don't think we can agree on that, so I'll just end it here.
        • MrBuddyCasino 3y ago
          Sad.