I have submitted a pull request for a new attachInterrupt implementation:
https://github.com/PaulStoffregen/cores/pull/182
The first commit primarily addresses issue 181, thread safety and slightly improves performance.
The second commit has a CTZ/CLZ-based implementation of the port -> pin interrupt dispatching functionality (this is used when attaching a pin interrupt via attachInterrupt) for Kinetis K (Teensy 3.x) and is much faster. Teensy LC doesn't have hardware support for CLZ and is excluded.
https://github.com/PaulStoffregen/cores/pull/182
The first commit primarily addresses issue 181, thread safety and slightly improves performance.
The second commit has a CTZ/CLZ-based implementation of the port -> pin interrupt dispatching functionality (this is used when attaching a pin interrupt via attachInterrupt) for Kinetis K (Teensy 3.x) and is much faster. Teensy LC doesn't have hardware support for CLZ and is excluded.