The config variable MICROPY_MODULE_FROZEN is now made of two separate
parts: MICROPY_MODULE_FROZEN_STR and MICROPY_MODULE_FROZEN_MPY. This
allows to have none, either or both of frozen strings and frozen mpy
files (aka frozen bytecode).
The idea is that if dupterm object can handle exceptions, it will handle
them itself. Otherwise, object state can be compromised and it's better
to terminate dupterm session. For example, disconnected socket will keep
throwing exceptions and dump messages about that.
nlr_pop must be called if no exception was raised.
Also, return value of these callback helpers is made void because ther
is (currently) no use for it.
Main entry point is _boot.py which checks whether FAT FS in flash mountable,
and if so, mounts it. Otherwise, it checks if flash is empty, and if so,
performs initial module setup: makes FAT FS, configures default AP name,
etc. As a last option, if flash is not empty, and could not be mounted,
it means filesystem corruption, and warning message with instructions is
printed in an infinite loop.
Upon start-up, _boot module is executed from frozen files to do early
initialization, e.g. create and mount the flash filesystem. Then
"boot.py" is executed if it exists in the filesystem. Finally, "main.py"
is executed if exists to allow start-on-boot user applications.
This allows a user to make a custom boot file or startup application
without recompiling the firmware, while letting to do early initialization
in Python code.
Based on RFC https://github.com/micropython/micropython/issues/1955.
With .rodata being in FlashROM now, gap can be much smaller now. InstRAM
can be max 32K, and with segment headers, that already makes it more than
32K. Then there's some .data still, and the next Flash page boundary is
0x9000. That figure should be more or less future-proof.
TODO: Refactor makeimg to take FlashROM segment offset from file name.
This was originally used for non-event based REPL processing. Then it
was unused when event-based processing was activated. But now that event
based is disabled, and non-event based is back, there has been new ring
buffer code to process the chars.
Event-driven loop (push-style) is still supported and default (controlled
by MICROPY_REPL_EVENT_DRIVEN setting, as expected).
Dedicated loop worked even without adding ets_loop_iter(), though that
needs to be revisited later.
Before this change, if REPL blocked executing some code, it was possible
to still input new statememts and excuting them, all leading to weird,
and portentially dangerous interaction.
TODO: Current implementation may have issues processing input accumulated
while REPL was blocked.
