Green Threads

The 200-line implementation of green threads from this tutorial with comments about the details I learned.

TODO

• Growable stacks
• x86-64 psABI stack layout and calling convention
  • Q: how %rsp register works in stack construction in spawn()
    • when ret
    • when to move to next byte
  • A: Princeton COS217 slide on "Assembly Langauge: Function Calls"
• why #[inline(never)] for switch()?

  • It's for stack alignment.

    In the perspective of one task, call switch sub %rsp for storing the %rip when suspended. When it's resumed, ret add %rsp back to the original aligned address.