alt Hacker News> Please note that even on fast computers this program struggles to simulate the C64 hardware at real speed. A real C64 is simulated at 31% of its speed on an Apple M3 Max, 39% on an AMD Ryzen AI Max+ PRO 495 (Gorgon Halo), and 48% on an Apple M5 Max
Key takeaway is why FPGA is still useful. Even modern CPUs can't handle certain seemingly simple data processing tasks in realtime.
No, this implementation is just horribly optimized (as usual). Just glancing at the source you could do easy 100x performance improvements with simple fixes.
ie no SIMD/SWAR anywhere; simulating things that literally don't need to be simulated; CPUs are emulated via monstrous instruction flooding cascades with ZERO reordering/speculative execution optimizations (this only improves performance, the underlying emulated program literally can't tell the difference, and with most emulators you'd get a FREE 5-20x improvement); cache trashing everywhere; zero multithreading (as far as I could tell, couldn't bother checking in detail)