Replace the ROTW-based register flush with a recursive call4 approach
that properly triggers hardware window-overflow exceptions. ROTW only
modifies WindowBase without saving registers, causing corruption when
switching goroutines. The recursive call4 correctly spills all 15 window
panes. Also clear WindowStart after the stack switch to prevent stale
overflow of garbage register values.
Add tinygo_task_current export for C interop.
Signed-off-by: deadprogram <ron@hybridgroup.com>
This is more descriptive: the call is to exit a task, not to pause it.
This also makes it more obvious that there's an optimization
opportunity: to free the stack explicitly after the goroutine returns
(or to keep it as a cache for the next stack allocation).
I managed to get CGo sort-of working in VSCode (meaning that it will
typecheck code in the IDE itself) using a few crude hacks, but it
requires a few minor changes to the TinyGo standard library.
I intend to eventually add this support in the TinyGo extension for
VSCode directly, but for now I've manually updated .vscode/settings.json
to get IDE support. In any case, it would be nice to have this for when
I hopefully add this to the TinyGo extension eventually.
This has been a *lot* of work, trying to understand the Xtensa windowed
registers ABI. But in the end I managed to come up with a very simple
implementation that so far seems to work very well.
I tested this with both blinky examples (with blinky2 slightly edited)
and ./testdata/coroutines.go to verify that it actually works.
Most development happened on the ESP32 QEMU fork from Espressif
(https://github.com/espressif/qemu/wiki) but I also verified that it
works on a real ESP32.
deadprogram
Ayke van Laethem
Dan Kegel