Sega Dreamcast

Boots an openly-licensed SH-4 demo (an animated RGB565 "XOR plaid") on a from-source WebAssembly build of a Hitachi SH-4 interpreter — the Dreamcast's CPU. Arrow keys = D-pad; Z = A, X = B, A = X, S = Y; Q = L trigger, W = R trigger; Enter = Start. The pressed buttons fold into the animation so input is visible. Use the on-screen Dreamcast pad on touch. Open the debugger to read the live SH-4 registers (R0-R15, PC, PR, SR, GBR, VBR, MACH/MACL, FPUL and FR0-FR15) and memory, single-step one SH-4 instruction at a time, set execution breakpoints and memory watchpoints, and pause/resume. Click the screen first so it captures the keyboard.