I don't know how practical that optimization would be in this particular use case, wouldn't that mean the context switch code would have to be inlined at every call site? Then when you switch back to that context how would you generate that code correctly? You would need to know which registers were not saved by green thread A, and not touched by green thread B. So the compiler would basically need to know the runtime behavior of your program to optimize pushing and popping context records, unless I misunderstood your point?
If you set a breakpoint in say a win32 fiber switch, and look at the disassembly, it jumps to an internal function that just saves all the registers (and flags) to the active context and restores all the registers from the resumed context every time. Don't know how more optimal that can be for the general case.
If you set a breakpoint in say a win32 fiber switch, and look at the disassembly, it jumps to an internal function that just saves all the registers (and flags) to the active context and restores all the registers from the resumed context every time. Don't know how more optimal that can be for the general case.