alt Hacker NewsLooks really cool and I'm going to take a closer look tonight!
How do you do the context switching between coroutines? getcontext/setcontext, or something more architecture specific? I'm currently working on some stackful coroutine stuff and the swapcontext calls actually take a fair amount of time, so I'm planning on writing a custom one that doesn't preserve unused bits (signal mask and FPU state). So I'm curious about your findings there
Hi, it is hand-coded assembly. Pushing all necessary registers to the stack (including GS on Windows), swapping the stack pointer to/from memory, popping the registers, and off we go on the other stack. I save FPU flags, but not more FPU state than necessary (which again is a whole lot more on Windows than on Linux).
Others have done this elsewhere, of course. There are links/references to several other examples in the code. I mention two in particular in the NOTICE file, not because I copied their code, but because I read it very closely and followed the outline of their examples. It would probably taken me forever to figure out the Windows TIB on my own.
What I think is pretty cool (biased as I am) in my implementation is the «trampoline» that launches the coroutine function and waits silently in case it returns. If it does, it is intercepted and the proper coroutine exit() function gets called.