The stm32 and nrf ports already had the behaviour that they would first
check if the script exists before executing it, and this patch makes all
other ports work the same way. This helps when developing apps because
it's hard to tell (when unconditionally trying to execute the scripts) if
the resulting OSError at boot up comes from missing boot.py or main.py, or
from some other error. And it's not really an error if these scripts don't
exist.
Replaces "PYB: soft reboot" with "MPY: soft reboot", etc.
Having a consistent prefix across ports reduces the difference between
ports, which is a general goal. And this change won't break pyboard.py
because that tool only looks for "soft reboot".
The individual union members (like SPI, I2C) are never used, only the
generic "reg" entry is. And the union names can clash with macro
definitions in the HAL so better to remove them.
Header files that are considered internal to the py core and should not
normally be included directly are:
py/nlr.h - internal nlr configuration and declarations
py/bc0.h - contains bytecode macro definitions
py/runtime0.h - contains basic runtime enums
Instead, the top-level header files to include are one of:
py/obj.h - includes runtime0.h and defines everything to use the
mp_obj_t type
py/runtime.h - includes mpstate.h and hence nlr.h, obj.h, runtime0.h,
and defines everything to use the general runtime support functions
Additional, specific headers (eg py/objlist.h) can be included if needed.
This is to keep the top-level directory clean, to make it clear what is
core and what is a port, and to allow the repository to grow with new ports
in a sustainable way.
