The existings mp_obj_type_t uses a sparse representation for slots for the
capability methods of the type (eg print, make_new). This commit adds a
compact slot-index representation. The basic idea is that where the
mp_obj_type_t struct used to have 12 pointer fields, it now has 12 uint8_t
indices, and a variable-length array of pointers. So in the best case (no
fields used) it saves 12x4-12=36 bytes (on a 32-bit machine) and in the
common case (three fields used) it saves 9x4-12=24 bytes.
Overall with all associated changes, this slot-index representation reduces
code size by 1000 to 3000 bytes on bare-metal ports. Performance is
marginally better on a few tests (eg about 1% better on misc_pystone.py and
misc_raytrace.py on PYBv1.1), but overall marginally worse by a percent or
so.
See issue #7542 for further analysis and discussion.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
Since commit e65d1e69e8 there is no longer an
io.FileIO class, so this option is no longer needed.
This option also controlled whether or not files supported being opened in
binary mode (eg 'rb'), and could, if disabled, lead to confusion as to why
opening a file in binary mode silently did the wrong thing (it would just
open in text mode if MICROPY_PY_IO_FILEIO was disabled).
The various VFS implementations (POSIX, FAT, LFS) were the only places
where enabling this option made a difference, and in almost all cases where
one of these filesystems were enabled, MICROPY_PY_IO_FILEIO was also
enabled. So it makes sense to just unconditionally enable this feature
(ability to open a file in binary mode) in all cases, and so just remove
this config option altogether. That makes configuration simpler and means
binary file support always exists (and opening a file in binary mode is
arguably more fundamental than opening in text mode, so if anything should
be configurable then it should be the ability to open in text mode).
Signed-off-by: Damien George <damien@micropython.org>
These were added in Python 3.5.
Enabled via MICROPY_PY_BUILTINS_BYTES_HEX, and enabled by default for all
ports that currently have ubinascii.
Rework ubinascii to use the implementation of these methods.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
This commit adds a new option MICROPY_GC_SPLIT_HEAP (disabled by default)
which, when enabled, allows the GC heap to be split over multiple memory
areas/regions. The first area is added with gc_init() and subsequent areas
can be added with gc_add(). New areas can be added at runtime. Areas are
stored internally as a linked list, and calls to gc_alloc() can be
satisfied from any area.
This feature has the following use-cases (among others):
- The ESP32 has a fragmented OS heap, so to use all (or more) of it the
GC heap must be split.
- Other MCUs may have disjoint RAM regions and are now able to use them
all for the GC heap.
- The user could explicitly increase the size of the GC heap.
- Support a dynamic heap while running on an OS, adding more heap when
necessary.
All in-tree uses of MICROPY_PORT_ROOT_POINTERS have been replaced with
MP_REGISTER_ROOT_POINTER(), so now we can remove both
MICROPY_PORT_ROOT_POINTERS and MICROPY_BOARD_ROOT_POINTERS from the code
and remaining config files.
Signed-off-by: David Lechner <david@pybricks.com>
This uses MP_REGISTER_ROOT_POINTER() to register the readline_history root
pointer array used by shared/readline.c and removes the registration from
all mpconfigport.h files.
This also required adding a new MICROPY_READLINE_HISTORY_SIZE config option
since not all ports used the same sized array.
Signed-off-by: David Lechner <david@pybricks.com>
This follows on from a5324a1074 and allows
mpy-cross to dynamically select whether ARMv7-M instructions are supported
in @micropython.asm_thumb functions.
The config option MICROPY_EMIT_INLINE_THUMB_ARMV7M is no longer needed, it
is now controlled by MICROPY_EMIT_THUMB_ARMV7M.
Signed-off-by: Damien George <damien@micropython.org>
Some architectures (like esp32 xtensa) cannot read byte-wise from
executable memory. This means the prelude for native functions -- which is
usually located after the machine code for the native function -- must be
placed in separate memory that can be read byte-wise. Prior to this commit
this was achieved by enabling N_PRELUDE_AS_BYTES_OBJ for the emitter and
MICROPY_EMIT_NATIVE_PRELUDE_AS_BYTES_OBJ for the runtime. The prelude was
then placed in a bytes object, pointed to by the module's constant table.
This behaviour is changed by this commit so that a pointer to the prelude
is stored either in mp_obj_fun_bc_t.child_table, or in
mp_obj_fun_bc_t.child_table[num_children] if num_children > 0. The reasons
for doing this are:
1. It decouples the native emitter from runtime requirements, the emitted
code no longer needs to know if the system it runs on can/can't read
byte-wise from executable memory.
2. It makes all ports have the same emitter behaviour, there is no longer
the N_PRELUDE_AS_BYTES_OBJ option.
3. The module's constant table is now used only for actual constants in the
Python code. This allows further optimisations to be done with the
constants (eg constant deduplication).
Code size change for those ports that enable the native emitter:
unix x64: +80 +0.015%
stm32: +24 +0.004% PYBV10
esp8266: +88 +0.013% GENERIC
esp32: -20 -0.002% GENERIC[incl -112(data)]
rp2: +32 +0.005% PICO
Signed-off-by: Damien George <damien@micropython.org>
Prior to this commit, even with unicode disabled .py and .mpy files could
contain unicode characters, eg by entering them directly in a string as
utf-8 encoded.
The only thing the compiler disallowed (with unicode disabled) was using
\uxxxx and \Uxxxxxxxx notation to specify a character within a string with
value >= 0x100; that would give a SyntaxError.
With this change mpy-cross will now accept \u and \U notation to insert a
character with value >= 0x100 into a string (because the -mno-unicode
option is now gone, there's no way to forbid this). The runtime will
happily work with strings with such characters, just like it already works
with strings with characters that were utf-8 encoded directly.
This change simplifies things because there are no longer any feature
flags in .mpy files, and any bytecode .mpy will now run on any target.
Signed-off-by: Damien George <damien@micropython.org>
This contains a string useful for identifying the underlying machine. This
string is kept consistent with the second part of the REPL banner via the
new config option MICROPY_BANNER_MACHINE.
This makes os.uname() more or less redundant, as all the information in
os.uname() is now available in the sys module.
Signed-off-by: Damien George <damien@micropython.org>
This commit adds the git hash and build date to sys.version. This is
allowed according to CPython docs, and is what PyPy does. The docs state:
A string containing the version number of the Python interpreter plus
additional information on the build number and compiler used.
Eg on CPython:
Python 3.10.4 (main, Mar 23 2022, 23:05:40) [GCC 11.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> sys.version
'3.10.4 (main, Mar 23 2022, 23:05:40) [GCC 11.2.0]'
and PyPy:
Python 2.7.12 (5.6.0+dfsg-4, Nov 20 2016, 10:43:30)
[PyPy 5.6.0 with GCC 6.2.0 20161109] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>>> import sys
>>>> sys.version
'2.7.12 (5.6.0+dfsg-4, Nov 20 2016, 10:43:30)\n[PyPy 5.6.0 with GCC ...
With this commit on MicroPython we now have:
MicroPython v1.18-371-g9d08eb024 on 2022-04-28; linux [GCC 11.2.0] v...
Use Ctrl-D to exit, Ctrl-E for paste mode
>>> import sys
>>> sys.version
'3.4.0; MicroPython v1.18-371-g9d08eb024 on 2022-04-28'
Note that the start of the banner is the same as the end of sys.version.
This helps to keep code size under control because the string can be reused
by the compiler.
Signed-off-by: Damien George <damien@micropython.org>
This commit adds support to the parser so that tuples which contain only
constant elements (bool, int, str, bytes, etc) are immediately converted to
a tuple object. This makes it more efficient to use tuples containing
constant data because they no longer need to be created at runtime by the
bytecode (or native code).
Furthermore, with this improvement constant tuples that are part of frozen
code are now able to be stored fully in ROM (this will be implemented in
later commits).
Code size is increased by about 400 bytes on Cortex-M4 platforms.
See related issue #722.
Signed-off-by: Damien George <damien@micropython.org>
If MICROPY_SCHEDULER_STATIC_NODES is enabled then C code can declare a
static mp_sched_node_t and schedule a callback using
mp_sched_schedule_node(). In contrast to using mp_sched_schedule(), the
node version will have at most one pending callback outstanding, and will
always be able to schedule if there is nothing already scheduled on this
node. This guarantees that the the callback will be called exactly once
after it is scheduled.
Signed-off-by: Damien George <damien@micropython.org>
This commit adds generic support for mutable module attributes on built in
modules, by adding support for an optional hook function for module
attribute lookup. If a module wants to support additional attribute load/
store/delete (beyond what is in the constant, globals dict) then it should
add at the very end of its globals dict MP_MODULE_ATTR_DELEGATION_ENTRY().
This should point to a custom function which will handle any additional
attributes.
The mp_module_generic_attr() function is provided as a helper function for
additional attributes: it requires an array of qstrs (terminated in
MP_QSTRnull) and a corresponding array of objects (with a 1-1 mapping
between qstrs and objects). If the qstr is found in the array then the
corresponding object is loaded/stored/deleted.
Signed-off-by: Damien George <damien@micropython.org>
Background: .mpy files are precompiled .py files, built using mpy-cross,
that contain compiled bytecode functions (and can also contain machine
code). The benefit of using an .mpy file over a .py file is that they are
faster to import and take less memory when importing. They are also
smaller on disk.
But the real benefit of .mpy files comes when they are frozen into the
firmware. This is done by loading the .mpy file during compilation of the
firmware and turning it into a set of big C data structures (the job of
mpy-tool.py), which are then compiled and downloaded into the ROM of a
device. These C data structures can be executed in-place, ie directly from
ROM. This makes importing even faster because there is very little to do,
and also means such frozen modules take up much less RAM (because their
bytecode stays in ROM).
The downside of frozen code is that it requires recompiling and reflashing
the entire firmware. This can be a big barrier to entry, slows down
development time, and makes it harder to do OTA updates of frozen code
(because the whole firmware must be updated).
This commit attempts to solve this problem by providing a solution that
sits between loading .mpy files into RAM and freezing them into the
firmware. The .mpy file format has been reworked so that it consists of
data and bytecode which is mostly static and ready to run in-place. If
these new .mpy files are located in flash/ROM which is memory addressable,
the .mpy file can be executed (mostly) in-place.
With this approach there is still a small amount of unpacking and linking
of the .mpy file that needs to be done when it's imported, but it's still
much better than loading an .mpy from disk into RAM (although not as good
as freezing .mpy files into the firmware).
The main trick to make static .mpy files is to adjust the bytecode so any
qstrs that it references now go through a lookup table to convert from
local qstr number in the module to global qstr number in the firmware.
That means the bytecode does not need linking/rewriting of qstrs when it's
loaded. Instead only a small qstr table needs to be built (and put in RAM)
at import time. This means the bytecode itself is static/constant and can
be used directly if it's in addressable memory. Also the qstr string data
in the .mpy file, and some constant object data, can be used directly.
Note that the qstr table is global to the module (ie not per function).
In more detail, in the VM what used to be (schematically):
qst = DECODE_QSTR_VALUE;
is now (schematically):
idx = DECODE_QSTR_INDEX;
qst = qstr_table[idx];
That allows the bytecode to be fixed at compile time and not need
relinking/rewriting of the qstr values. Only qstr_table needs to be linked
when the .mpy is loaded.
Incidentally, this helps to reduce the size of bytecode because what used
to be 2-byte qstr values in the bytecode are now (mostly) 1-byte indices.
If the module uses the same qstr more than two times then the bytecode is
smaller than before.
The following changes are measured for this commit compared to the
previous (the baseline):
- average 7%-9% reduction in size of .mpy files
- frozen code size is reduced by about 5%-7%
- importing .py files uses about 5% less RAM in total
- importing .mpy files uses about 4% less RAM in total
- importing .py and .mpy files takes about the same time as before
The qstr indirection in the bytecode has only a small impact on VM
performance. For stm32 on PYBv1.0 the performance change of this commit
is:
diff of scores (higher is better)
N=100 M=100 baseline -> this-commit diff diff% (error%)
bm_chaos.py 371.07 -> 357.39 : -13.68 = -3.687% (+/-0.02%)
bm_fannkuch.py 78.72 -> 77.49 : -1.23 = -1.563% (+/-0.01%)
bm_fft.py 2591.73 -> 2539.28 : -52.45 = -2.024% (+/-0.00%)
bm_float.py 6034.93 -> 5908.30 : -126.63 = -2.098% (+/-0.01%)
bm_hexiom.py 48.96 -> 47.93 : -1.03 = -2.104% (+/-0.00%)
bm_nqueens.py 4510.63 -> 4459.94 : -50.69 = -1.124% (+/-0.00%)
bm_pidigits.py 650.28 -> 644.96 : -5.32 = -0.818% (+/-0.23%)
core_import_mpy_multi.py 564.77 -> 581.49 : +16.72 = +2.960% (+/-0.01%)
core_import_mpy_single.py 68.67 -> 67.16 : -1.51 = -2.199% (+/-0.01%)
core_qstr.py 64.16 -> 64.12 : -0.04 = -0.062% (+/-0.00%)
core_yield_from.py 362.58 -> 354.50 : -8.08 = -2.228% (+/-0.00%)
misc_aes.py 429.69 -> 405.59 : -24.10 = -5.609% (+/-0.01%)
misc_mandel.py 3485.13 -> 3416.51 : -68.62 = -1.969% (+/-0.00%)
misc_pystone.py 2496.53 -> 2405.56 : -90.97 = -3.644% (+/-0.01%)
misc_raytrace.py 381.47 -> 374.01 : -7.46 = -1.956% (+/-0.01%)
viper_call0.py 576.73 -> 572.49 : -4.24 = -0.735% (+/-0.04%)
viper_call1a.py 550.37 -> 546.21 : -4.16 = -0.756% (+/-0.09%)
viper_call1b.py 438.23 -> 435.68 : -2.55 = -0.582% (+/-0.06%)
viper_call1c.py 442.84 -> 440.04 : -2.80 = -0.632% (+/-0.08%)
viper_call2a.py 536.31 -> 532.35 : -3.96 = -0.738% (+/-0.06%)
viper_call2b.py 382.34 -> 377.07 : -5.27 = -1.378% (+/-0.03%)
And for unix on x64:
diff of scores (higher is better)
N=2000 M=2000 baseline -> this-commit diff diff% (error%)
bm_chaos.py 13594.20 -> 13073.84 : -520.36 = -3.828% (+/-5.44%)
bm_fannkuch.py 60.63 -> 59.58 : -1.05 = -1.732% (+/-3.01%)
bm_fft.py 112009.15 -> 111603.32 : -405.83 = -0.362% (+/-4.03%)
bm_float.py 246202.55 -> 247923.81 : +1721.26 = +0.699% (+/-2.79%)
bm_hexiom.py 615.65 -> 617.21 : +1.56 = +0.253% (+/-1.64%)
bm_nqueens.py 215807.95 -> 215600.96 : -206.99 = -0.096% (+/-3.52%)
bm_pidigits.py 8246.74 -> 8422.82 : +176.08 = +2.135% (+/-3.64%)
misc_aes.py 16133.00 -> 16452.74 : +319.74 = +1.982% (+/-1.50%)
misc_mandel.py 128146.69 -> 130796.43 : +2649.74 = +2.068% (+/-3.18%)
misc_pystone.py 83811.49 -> 83124.85 : -686.64 = -0.819% (+/-1.03%)
misc_raytrace.py 21688.02 -> 21385.10 : -302.92 = -1.397% (+/-3.20%)
The code size change is (firmware with a lot of frozen code benefits the
most):
bare-arm: +396 +0.697%
minimal x86: +1595 +0.979% [incl +32(data)]
unix x64: +2408 +0.470% [incl +800(data)]
unix nanbox: +1396 +0.309% [incl -96(data)]
stm32: -1256 -0.318% PYBV10
cc3200: +288 +0.157%
esp8266: -260 -0.037% GENERIC
esp32: -216 -0.014% GENERIC[incl -1072(data)]
nrf: +116 +0.067% pca10040
rp2: -664 -0.135% PICO
samd: +844 +0.607% ADAFRUIT_ITSYBITSY_M4_EXPRESS
As part of this change the .mpy file format version is bumped to version 6.
And mpy-tool.py has been improved to provide a good visualisation of the
contents of .mpy files.
In summary: this commit changes the bytecode to use qstr indirection, and
reworks the .mpy file format to be simpler and allow .mpy files to be
executed in-place. Performance is not impacted too much. Eventually it
will be possible to store such .mpy files in a linear, read-only, memory-
mappable filesystem so they can be executed from flash/ROM. This will
essentially be able to replace frozen code for most applications.
Signed-off-by: Damien George <damien@micropython.org>
The mp_sys_path_obj and mp_sys_argv_obj objects are only used by the
runtime and accessible from Python if MICROPY_PY_SYS is enabled. So
exclude them from the runtime state if this option is disabled.
Signed-off-by: Damien George <damien@micropython.org>
If MICROPY_PY_SYS_PATH_ARGV_DEFAULTS is enabled (which it is by default)
then sys.path and sys.argv will be initialised and populated with default
values. This keeps all bare-metal ports aligned.
Signed-off-by: Damien George <damien@micropython.org>
This feature is not enabled on any port, it's not in CPython's io module,
and functionality is better suited to the micropython-lib implementation of
pkg_resources.
This makes it possible for cooperative multitasking systems to keep running
event loops during garbage collector operations.
For example, this can be used to ensure that a motor control loop runs
approximately each 5 ms. Without this hook, the loop time can jump to
about 15 ms.
Addresses #3475.
Signed-off-by: Laurens Valk <laurens@pybricks.com>
This is an stm32-specific feature that's accessed via the pyb module, so
not something that will be widely enabled.
Signed-off-by: Damien George <damien@micropython.org>
Some of these will later be moved to CORE or BASIC, but EXTRA is a good
starting point based on what stm32 uses.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
This commit removes all parts of code associated with the existing
MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE optimisation option, including the
-mcache-lookup-bc option to mpy-cross.
This feature originally provided a significant performance boost for Unix,
but wasn't able to be enabled for MCU targets (due to frozen bytecode), and
added significant extra complexity to generating and distributing .mpy
files.
The equivalent performance gain is now provided by the combination of
MICROPY_OPT_LOAD_ATTR_FAST_PATH and MICROPY_OPT_MAP_LOOKUP_CACHE (which has
been enabled on the unix port in the previous commit).
It's hard to provide precise performance numbers, but tests have been run
on a wide variety of architectures (x86-64, ARM Cortex, Aarch64, RISC-V,
xtensa) and they all generally agree on the qualitative improvements seen
by the combination of MICROPY_OPT_LOAD_ATTR_FAST_PATH and
MICROPY_OPT_MAP_LOOKUP_CACHE.
For example, on a "quiet" Linux x64 environment (i3-5010U @ 2.10GHz) the
change from CACHE_MAP_LOOKUP_IN_BYTECODE, to LOAD_ATTR_FAST_PATH combined
with MAP_LOOKUP_CACHE is:
diff of scores (higher is better)
N=2000 M=2000 bccache -> attrmapcache diff diff% (error%)
bm_chaos.py 13742.56 -> 13905.67 : +163.11 = +1.187% (+/-3.75%)
bm_fannkuch.py 60.13 -> 61.34 : +1.21 = +2.012% (+/-2.11%)
bm_fft.py 113083.20 -> 114793.68 : +1710.48 = +1.513% (+/-1.57%)
bm_float.py 256552.80 -> 243908.29 : -12644.51 = -4.929% (+/-1.90%)
bm_hexiom.py 521.93 -> 625.41 : +103.48 = +19.826% (+/-0.40%)
bm_nqueens.py 197544.25 -> 217713.12 : +20168.87 = +10.210% (+/-3.01%)
bm_pidigits.py 8072.98 -> 8198.75 : +125.77 = +1.558% (+/-3.22%)
misc_aes.py 17283.45 -> 16480.52 : -802.93 = -4.646% (+/-0.82%)
misc_mandel.py 99083.99 -> 128939.84 : +29855.85 = +30.132% (+/-5.88%)
misc_pystone.py 83860.10 -> 82592.56 : -1267.54 = -1.511% (+/-2.27%)
misc_raytrace.py 21490.40 -> 22227.23 : +736.83 = +3.429% (+/-1.88%)
This shows that the new optimisations are at least as good as the existing
inline-bytecode-caching, and are sometimes much better (because the new
ones apply caching to a wider variety of map lookups).
The new optimisations can also benefit code generated by the native
emitter, because they apply to the runtime rather than the generated code.
The improvement for the native emitter when LOAD_ATTR_FAST_PATH and
MAP_LOOKUP_CACHE are enabled is (same Linux environment as above):
diff of scores (higher is better)
N=2000 M=2000 native -> nat-attrmapcache diff diff% (error%)
bm_chaos.py 14130.62 -> 15464.68 : +1334.06 = +9.441% (+/-7.11%)
bm_fannkuch.py 74.96 -> 76.16 : +1.20 = +1.601% (+/-1.80%)
bm_fft.py 166682.99 -> 168221.86 : +1538.87 = +0.923% (+/-4.20%)
bm_float.py 233415.23 -> 265524.90 : +32109.67 = +13.756% (+/-2.57%)
bm_hexiom.py 628.59 -> 734.17 : +105.58 = +16.796% (+/-1.39%)
bm_nqueens.py 225418.44 -> 232926.45 : +7508.01 = +3.331% (+/-3.10%)
bm_pidigits.py 6322.00 -> 6379.52 : +57.52 = +0.910% (+/-5.62%)
misc_aes.py 20670.10 -> 27223.18 : +6553.08 = +31.703% (+/-1.56%)
misc_mandel.py 138221.11 -> 152014.01 : +13792.90 = +9.979% (+/-2.46%)
misc_pystone.py 85032.14 -> 105681.44 : +20649.30 = +24.284% (+/-2.25%)
misc_raytrace.py 19800.01 -> 23350.73 : +3550.72 = +17.933% (+/-2.79%)
In summary, compared to MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE, the new
MICROPY_OPT_LOAD_ATTR_FAST_PATH and MICROPY_OPT_MAP_LOOKUP_CACHE options:
- are simpler;
- take less code size;
- are faster (generally);
- work with code generated by the native emitter;
- can be used on embedded targets with a small and constant RAM overhead;
- allow the same .mpy bytecode to run on all targets.
See #7680 for further discussion. And see also #7653 for a discussion
about simplifying mpy-cross options.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
The existing inline bytecode caching optimisation, selected by
MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE, reserves an extra byte in the
bytecode after certain opcodes, which at runtime stores a map index of the
likely location of this field when looking up the qstr. This scheme is
incompatible with bytecode-in-ROM, and doesn't work with native generated
code. It also stores bytecode in .mpy files which is of a different format
to when the feature is disabled, making generation of .mpy files more
complex.
This commit provides an alternative optimisation via an approach that adds
a global cache for map offsets, then all mp_map_lookup operations use it.
It's less precise than bytecode caching, but allows the cache to be
independent and external to the bytecode that is executing. It also works
for the native emitter and adds a similar performance boost on top of the
gain already provided by the native emitter.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
When the LOAD_ATTR opcode is executed there are quite a few different cases
that have to be handled, but the common case is accessing a member on an
instance type. Typically, built-in types provide methods which is why this
is common.
Fortunately, for this specific case, if the member is found in the member
map then there's no further processing.
This optimisation does a relatively cheap check (type is instance) and then
forwards directly to the member map lookup, falling back to the regular
path if necessary.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
This is the beginning of a set of changes to simplify enabling/disabling
features. The goals are:
- Remove redundancy from mpconfigport.h (never set a value to the default
-- make it clear exactly what's being enabled).
- Improve consistency between ports. All "similar" ports (i.e. approx same
flash size) should get the same features.
- Simplify mpconfigport.h -- just get default/sensible options for the size
of the port.
- Make it easy for defining constrained boards (e.g. STM32F0/L0), they can
just set a lower level.
This commit makes a step towards this and defines the "core" level as the
current default feature set, and a "minimal" level to turn off everything.
And a few placeholder levels are added for where the other ports will
roughly land.
This is a no-op change for all ports.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
The zephyr port doesn't support SoftI2C so it's not enabled, and the legacy
I2C constructor check can be removed.
Signed-off-by: Damien George <damien@micropython.org>
Jim Mussared