chaoran / fibril Goto Github PK

Return value is more natural to use.
Instead of writing fibril_fork(&fr, x, fib, (n-1)), we should use x = fibril_fork(&fr, fib, (n-1)).

The Prologue should do:

1. flush caller-saved registers
2. save callee-saved registers
3. push frame onto deque

The Epilogue should do:

1. pop frame from deque
2. if failed:
3. write return value
4. try to resume the frame

The prologue should guarantee that after caller-saved registers are flushed onto stack, their value is preserved (remain unchanged) through the whole forking process.

When a thief steals the continuation, it should resume execution right after the last instruction of the forking process. The instructions after that should restore flushed caller-saved registers first.

The existing approach: initialize the bp and sp at fibril_init might be a bug. Considering the case when the fibril frame is initialized in a function different from where it is used to fork, the theif may resume with the wrong bp and sp.

This should reduce overhead when executing the code in serial.