Cycle accuracy

A cycle-accurate emulator reproduces the original CPU's behavior on a per-clock-cycle basis, not just at a per-instruction level. This matters for games that rely on precise timing — graphical effects driven by mid-scanline register changes, audio mixing locked to vertical blank, copy protection that times memory reads. bsnes "accuracy" core is the canonical example for SNES; less-accurate cores run faster but miss-render certain effects. Browser emulation typically trades some accuracy for speed because WebAssembly's overhead makes the most-accurate cores too slow on mobile.