I'm designing a custom VM and am curious about how many registers I should use. Initially, I had 255, but I'm a little concerned about backing 255 pointers (a whole KB) on to the stack or heap every time I call a function, when most of them won't even be used. How many registers should I use?
Sorry guys. I made a stupid on this one. Turns out that I already had a vector of registers to optimize access to the stack, which I totally forgot about. Instead of duping them, I just set the registers in the state to be a reference to the stack's registers. Now all I need to do is specialize pushing to push straight to a register, and problem solved in a nice efficient fashion. These registers will also never need backing, since there's nothing function-dependent about them, and they'll grow in perfect accordance with my stack. It had just never occurred to me that I could push values into them without pushing an equivalent value into the stack.
The absolutely hideous template mess this is turning into for simple design concepts though is making me extremely unhappy. Want to buy: static if and variadic templates.