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.

Should raise TypeError, unless it's (in)equality comparison.

If __iop__ is not defined, call __op__ instead. This is desired behavior
for immutable types, __iop__ needs to be defined only for mutable types.

There are 2 changes:
- remove early initialisation of LSE and replaced it by LSEDRIVE config
  (there is no reason to call HAL_RCC_OscConfig twice).
- add initialisation of the variables PLLSAI1Source and PLLSAI1M as they
  are needed in Cube HAL 1.8.1.

IEEE floating point is specified such that a comparison of NaN with itself
returns false, and Python respects these semantics.  This patch makes uPy
also have these semantics.  The fix has a minor impact on the speed of the
object-equality fast-path, but that seems to be unavoidable and it's much
more important to have correct behaviour (especially in this case where
the wrong answer for nan==nan is silently returned).

These are now returned as "operation not supported" instead of raising
TypeError. In particular, this fixes equality for float vs incompatible
types, which now properly results in False instead of exception. This
also paves the road to support reverse operation (e.g. __radd__) with
float objects.

This is achieved by introducing mp_obj_get_float_maybe(), similar to
existing mp_obj_get_int_maybe().

"b" on Thumb might not be long enough for the jump to nlr_push_tail so it
must be done indirectly.

They are not used by any component and take up valuable flash space.

Prior to this patch, the size of the buffer given to pack_into() was checked
for being too small by using the count of the arguments, not their actual
size.  For example, a format spec of '4I' would only check that there was 4
bytes available, not 16; and 'I' would check for 1 byte, not 4.

The pack() function is ok because its buffer is created to be exactly the
correct size.

The fix in this patch calculates the total size of the format spec at the
start of pack_into() and verifies that the buffer is large enough.  This
adds some computational overhead, to iterate through the whole format spec.
The alternative is to check during the packing, but that requires extra
code to handle alignment, and the check is anyway not needed for pack().
So to maintain minimal code size the check is done using struct_calcsize.

Prior to this patch, the size of the buffer given to unpack/unpack_from was
checked for being too small by using the count of the arguments, not their
actual size.  For example, a format spec of '4I' would only check that
there was 4 bytes available, not 16; and 'I' would check for 1 byte, not 4.

This bug is fixed in this patch by calculating the total size of the format
spec at the start of the unpacking function.  This function anyway needs to
calculate the number of items at the start, so calculating the total size
can be done at the same time.

This patch makes a repeat counter behave the same as repeating the
typecode, when there are not enough args.  For example:
struct.pack('2I', 1) now behave the same as struct.pack('II', 1).

Similar to the existing testcase, but test that returning both value of
native type and instance of another user class from __new__ lead to
__init__ not being called, for better coverage.

Maps are always allocated "statically" and (de)initialised via mp_map_init
and mp_map_deinit.

Now traces more explicitly thru the lookup process.

Make messages more verbose and easier to follow and check that user class'
__new__() is not called by object.__new__(user_class).

This comment style is no longer used because the docs are written by hand,
not generated.

This is to have consistency across the whole repository.

NotImplemented means "try other fallbacks (like calling __rop__
instead of __op__) and if nothing works, raise TypeError". As
MicroPython doesn't implement any fallbacks, signal to raise
TypeError right away.

This upgrades the HAL to the versions:
- F4 V1.16.0
- F7 V1.7.0
- L4 V1.8.1

The main changes were in the SD card driver.  The vendor changed the SD
read/write functions to accept block number intead of byte address, so
there is no longer any need for a custom patch for this in stm32lib.
The CardType values also changed, so pyb.SDCard().info() will return
different values for the 3rd element of the tuple, but this function was
never documented.

Linked to https://github.com/micropython/stm32lib

The unary-op/binary-op enums are already defined, and there are no
arithmetic tricks used with these types, so it makes sense to use the
correct enum type for arguments that take these values.  It also reduces
code size quite a bit for nan-boxing builds.

Using gcc -Wpedantic will warn that #define of defined() is non-portable
and this patch fixes this.