A nice way to implement this is with a frame budget. You simply keep a variable that keeps track of how many miliseconds of budget you have left. Every time you

A nice way to implement this is with a frame budget. You simply keep a variable that keeps track of how many miliseconds of budget you have left. Every time you render to the screen you increase the budget by 1000/fps. Then you simply run the emulation until the budget runs out. if the emulation gets too far ahead of the rendering you can consume extra budget by simply sleeping -- which is now less important to get exactly right, you can simply sleep away 90% of the budget for example, so if the sleep overshoots you've got some play.