Commit Graph

64 Commits

Author SHA1 Message Date
Jim Mussared
f5f9edf645 all: Rename UMODULE to MODULE in preprocessor/Makefile vars.
This work was funded through GitHub Sponsors.

Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
2023-06-08 17:54:11 +10:00
Jim Mussared
7f5d5c7271 all: Rename mod_umodule*, ^umodule* to remove the "u" prefix.
This work was funded through GitHub Sponsors.

Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
2023-06-08 17:54:07 +10:00
Jim Mussared
dfe232d000 py/builtinimport: Remove weak links.
In order to keep "import umodule" working, the existing mechanism is
replaced with a simple fallback to drop the "u".

This makes importing of built-ins no longer touch the filesystem, which
makes a typical built-in import take ~0.15ms rather than 3-5ms.

(Weak links were added in c14a81662c)

This work was funded through GitHub Sponsors.

Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
2023-06-08 17:54:04 +10:00
Damien George
38243cd8e0 extmod/machine_pwm: Remove PWM_INIT and PWM_DUTY_U16_NS config options.
All ports that enable MICROPY_PY_MACHINE_PWM now enable these two
sub-options, so remove these sub-options altogether to force consistency in
new ports that implement machine.PWM.

Signed-off-by: Damien George <damien@micropython.org>
2023-05-04 13:19:19 +10:00
Damien George
a3c427898e nrf/modules/utime: Use extmod version of time module.
API additions;
- time.sleep() is added
- time.ticks_cpu() is added, but it just returns 0

No API or functional change to existing time functions.

Signed-off-by: Damien George <damien@micropython.org>
2023-04-27 15:11:51 +10:00
robert-hh
be686e634e rp2: Allow disabling USB via MICROPY_HW_ENABLE_USBDEV config.
Previously, setting MICROPY_HW_ENABLE_USBDEV to 0 caused build errors.  The
change affects the nrf and samd ports as well, so MICROPY_HW_ENABLE_USBDEV
had to be explicitly enabled there.

The configuration options MICROPY_HW_ENABLE_USBDEV and
MICROPY_HW_ENABLE_UART_REPL are independent, and can be enabled or disabled
by a board.

Signed-off-by: Damien George <damien@micropython.org>
2023-03-20 22:33:45 +11:00
robert-hh
e3b877826c nrf/modules/machine/soft_pwm: Add PWM for nrf51x boards using soft PWM.
Using extmod/machine_pwm.c for the Python bindings and the existing
softpwm.c driver, by just adding the interface.

Properties:
- Frequency range 1-3906 Hz.
- All PWM outputs run at the same frequency but can have different duty
  cycles.
- Limited to the P0.x pins.

Since it uses the existing softpwm.c mechanism, it will be affected by
playing music with the music class.
2023-03-10 10:44:02 +11:00
robert-hh
a1f838cdf1 nrf/modules/machine/pwm: Use extmod/machine_pwm.c for PWM module.
This is a breaking change, making the hardware PWM on the nrf port
compatible with the other ports providing machine.PWM.

Frequency range 4Hz - ~5.4 MHz.  The base clock range is 125kHz to 16 MHz,
and the divider range is 3 - 32767.

The hardware supports up to four outputs per PWM device with different duty
cycles, but only one output is (and was) supported.
2023-03-10 10:43:55 +11:00
robert-hh
0baf6c80d9 nrf/mpconfigport: Enable seeding of the PRNG by the hardware RNG.
A suitable function already existed, so just the declaration was needed.
2023-01-28 15:23:26 +11:00
Damien George
e8f5cfe0e1 nrf: Rename MICROPY_PY_MACHINE_TIMER to MICROPY_PY_MACHINE_TIMER_NRF.
So that it doesn't clash with the extmod version.

Also make the default for this enabled, so that most boards do not need to
configure it.

Signed-off-by: Damien George <damien@micropython.org>
2022-10-27 14:30:58 +11:00
Damien George
8f4c108025 all: Remove MICROPY_PY_IO_FILEIO config option.
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>
2022-08-18 11:54:17 +10:00
Jim Mussared
092784da19 ports: Remove unused mp_type_{fileio/textio} macros in mpconfigport.h.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
2022-07-26 18:07:22 +10:00
robert-hh
80339f1a33 ports: Adapt mimxrt, nrf and rp2 ports to work with latest TinyUSB.
rp2: change tud_task() to tud_task_ext().

mimxrt: use lib/tinyusb/src/portable/chipidea/ci_hs/dcd_ci_hs.c instead of
lib/tinyusb/src/portable/nxp/transdimension/dcd_transdimension.c.

nrf: add a definition for the changed tud_task().  tud_task() is changed
to tud_task_ext(), and the #define for backward compatibility is in
src/device/usbd.h.

The items I know which are fixed with this version:
- Fix for the SAMD USB lock-up.
- Support the MIMXRT11XX series of MCUs.
- Fix a wrong pin definition for MIMXRT1050_EVKB.

Tested with the MIMXRT boards, rp2 Pico, SAMD boards, nrf board.
2022-07-19 11:27:21 +10:00
David Lechner
8a69c54211 nrf: Use MP_REGISTER_ROOT_POINTER().
This uses MP_REGISTER_ROOT_POINTER() to register all port-specific root
pointers for the nrf port.

Signed-off-by: David Lechner <david@pybricks.com>
2022-07-18 13:50:34 +10:00
David Lechner
81dbea1ce3 shared/readline: Use MP_REGISTER_ROOT_POINTER().
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>
2022-07-18 13:48:49 +10:00
robert-hh
be6f0f3b3b nrf/mpconfigport: Call tud_task() in MICROPY_EVENT_POLL_HOOK.
So that the interrupt character can interrupt a long-running loop, like a
sleep.
2022-07-17 00:12:34 +10:00
iabdalkader
262f4a4855 nrf/mpconfigport: Remove obsolete module declarations.
External module declarations are no longer used/needed after the
introduction of MP_REGISTER_MODULE.
2022-07-15 22:54:25 +10:00
iabdalkader
425d8fc0d6 nrf: Enable optional support for Arduino 1200bps touch.
Individual boards must enable it via MICROPY_HW_USB_CDC_1200BPS_TOUCH.
2022-06-23 14:33:40 +10:00
iabdalkader
d8f5669532 nrf/modmachine: Add machine.bootloader() and make it customisable. 2022-06-17 13:37:44 +10:00
iabdalkader
921dd94676 nrf/main: Add startup and early-init board hook macros.
Following stm32 for naming and location of the hooks.  Also allow a board
to provide custom .c files to implement code for these hooks.
2022-06-17 13:23:45 +10:00
Andrew Leech
494e8ba722 nrf/mpconfigport: Fix MICROPY_VFS IO build support. 2022-06-03 12:39:43 +10:00
Andrew Leech
c5878dd1f9 nrf/mpconfigport: Enable extra features as defined by ROM levels.
This commit enables extra features from the ROM levels and further
simplifies mpconfigport.h.  The changes are:

- NRF51822 & BLUETOOTH_SD -> MICROPY_CONFIG_ROM_LEVEL_MINIMUM
    - no changes

- NRF51822 -> MICROPY_CONFIG_ROM_LEVEL_CORE_FEATURES
    - MICROPY_PY_IO = 1

- NRF52832 -> MICROPY_CONFIG_ROM_LEVEL_BASIC_FEATURES
    - MICROPY_PY_IO = 1

- NRF52840, NRF9160 -> MICROPY_CONFIG_ROM_LEVEL_EXTRA_FEATURES
    - MICROPY_COMP_MODULE_CONST = 1
    - MICROPY_COMP_TRIPLE_TUPLE_ASSIGN = 1
    - MICROPY_OPT_MPZ_BITWISE = 1
    - MICROPY_PY_ALL_SPECIAL_METHODS = 1
    - MICROPY_PY_BUILTINS_EXECFILE = 1
    - MICROPY_PY_BUILTINS_SLICE_ATTRS = 1
    - MICROPY_PY_BUILTINS_STR_CENTER = 1
    - MICROPY_PY_BUILTINS_STR_PARTITION = 1
    - MICROPY_PY_BUILTINS_STR_SPLITLINES = 1
    - MICROPY_PY_CMATH = 1
    - MICROPY_PY_COLLECTIONS_ORDEREDDICT = 1
    - MICROPY_PY_FRAMEBUF = 1
    - MICROPY_PY_IO = 1
    - MICROPY_PY_MATH_SPECIAL_FUNCTIONS = 1
    - MICROPY_PY_SYS_STDIO_BUFFER = 1
    - MICROPY_PY_UCTYPES = 1
    - MICROPY_PY_UHEAPQ = 1
    - MICROPY_PY_UJSON = 1
    - MICROPY_PY_URE = 1
    - MICROPY_PY_UZLIB = 1
    - MICROPY_REPL_EMACS_KEYS = 1
2022-06-03 12:37:12 +10:00
Andrew Leech
13f5d38f2e nrf/mpconfigport: Set MICROPY_CONFIG_ROM_LEVEL defines for each MCU.
This commit is a no-op change to simplify existing config.
2022-06-03 12:36:40 +10:00
Damien George
6e71cde6aa ports: Use default VFS config for import_stat and builtin_open.
For ports with MICROPY_VFS and MICROPY_PY_IO enabled their configuration
can now be simplified to use the defaults for mp_import_stat and
mp_builtin_open.

This commit makes no functional change, except for the following minor
points:
- the built-in "open" is removed from the minimal port (it previously did
  nothing)
- the duplicate built-in "input" is removed from the esp32 port
- qemu-arm now delegates to VFS import/open

Signed-off-by: Damien George <damien@micropython.org>
2022-05-25 13:04:45 +10:00
Jim Mussared
f67ac90fa9 nrf: Make port-specific modules use MP_REGISTER_MODULE.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
2022-05-18 20:57:09 +10:00
Damien George
fbd47fc46c ports: Consolidate inclusion of umachine module in built-ins.
The inclusion of `umachine` in the list of built-in modules is now done
centrally in py/objmodule.c.  Enabling MICROPY_PY_MACHINE will include this
module.

As part of this, all ports now have `umachine` as the core module name
(previously some had only `machine` as the name).

Signed-off-by: Damien George <damien@micropython.org>
2022-02-03 10:08:54 +11:00
Jim Mussared
b326edf68c all: Remove MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE.
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>
2021-09-16 16:04:03 +10:00
Damien George
122d901ef1 extmod/machine_i2c: Make SoftI2C configurable via macro option.
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>
2021-09-02 13:11:23 +10:00
Daniel Mizyrycki
8f45f5ee4f nrf: Set .mpy features consistent with documentation and other ports.
This allows nrf devices to load .mpy files.  And nrf52840 and nrf9160 based
boards also support compiling and loading native code.
2021-08-13 23:22:54 +10:00
Daniel Mizyrycki
8645b7c23b nrf: Enable source line on tracebacks. 2021-08-09 15:09:33 +10:00
Glenn Ruben Bakke
f99aa82e85 nrf/mpconfigport.h: Enable MICROPY_PY_IO_FILEIO when an FS is enabled.
Enable MICROPY_PY_IO_FILEIO if MICROPY_VFS_FAT, MICROPY_VFS_LFS1
or MICROPY_VFS2 has been enabled.
2021-08-08 23:09:26 +10:00
Glenn Ruben Bakke
c9b72ba694 nrf/mpconfigport.h: Tune FAT FS configuration.
Disable MICROPY_FATFS_MULTI_PARTITION configuration because there is no
partition table in the flash for FATFS to read.

Also, set MICROPY_FATFS_MAX_SS to the size of a flash page.  For nrf51 the
value 1024 is set.  For nrf52/nrf91 the value 4096 is set.
2021-08-08 23:09:26 +10:00
Glenn Ruben Bakke
85cad50266 nrf/mpconfigport.h: Expose nrf module when MICROPY_PY_NRF is set. 2021-08-08 23:09:26 +10:00
Zoltán Vörös
8c02b94946 nrf: Add more math sources to Makefile, and enable log2 implementation.
This commit adds a few math functions to the source list in the Makefile,
and implements the log2f function, so that ulab can be compiled on the nrf
boards.  It also addresses part of #5162.
2021-06-08 16:39:47 +10:00
Bruno Martins
94fb5e7f5a nrf: Add machine.memXX, and allow boards to customise some features. 2021-05-18 12:01:51 +10:00
Damien George
ad4656b861 all: Rename BYTES_PER_WORD to MP_BYTES_PER_OBJ_WORD.
The "word" referred to by BYTES_PER_WORD is actually the size of mp_obj_t
which is not always the same as the size of a pointer on the target
architecture.  So rename this config value to better reflect what it
measures, and also prefix it with MP_.

For uses of BYTES_PER_WORD in setting the stack limit this has been
changed to sizeof(void *), because the stack usually grows with
machine-word sized values (eg an nlr_buf_t has many machine words in it).

Signed-off-by: Damien George <damien@micropython.org>
2021-02-04 22:46:42 +11:00
Damien George
7c44354592 ports: Remove def of MP_PLAT_PRINT_STRN if it's the same as the default.
To simplify config, there's no need to specify MP_PLAT_PRINT_STRN if it's
the same as the default definition in py/mpconfig.h.

Signed-off-by: Damien George <damien@micropython.org>
2021-02-04 22:39:17 +11:00
Damien George
aaed33896b extmod/machine_i2c: Remove "id" arg in SoftI2C constructor.
The SoftI2C constructor is now used soley to create SoftI2C instances, it
can no longer delegate to create a hardware-based I2C instance.

Signed-off-by: Damien George <damien@micropython.org>
2020-10-01 12:57:10 +10:00
Damien George
27e117307d nrf: Remove unnecessary includes of mpconfigport.h and its header guard.
The mpconfigport.h file is an internal header and should only ever be
included once by mpconfig.h.

Signed-off-by: Damien George <damien@micropython.org>
2020-09-09 00:13:34 +10:00
Glenn Ruben Bakke
caaaa2b1f4 nrf: Enable more features for all targets.
Enabling the following features for all targets, except for nrf51
targets compiled to be used with SoftDevice:

- MICROPY_PY_ARRAY_SLICE_ASSIGN
- MICROPY_PY_SYS_STDFILES
- MICROPY_PY_UBINASCII
2020-07-22 12:54:20 +02:00
Glenn Ruben Bakke
0a79e18398 nrf: Split mpconfigport.h into multiple files.
Splitting mpconfigport.h into multiple device specific
files in order to facilitate variations between devices.

Due to the fact that the devices might have variations in
features and also variations in flash size it makes sense
that some devices offers more functionality than others
without being limited by restricted devices.

For example more micropython features can be activated for
nrf52840 with 1MB flash, compared to nrf51 with 256KB.
2020-07-22 12:54:20 +02:00
Martin Fischer
59ed3bdd9f nrf: Enable nrf tick support on all boards by default.
Having time.ticks_ms/us/add/diff is very useful and used by many drivers,
libraries and components.
2020-07-08 23:47:08 +10:00
Martin Fischer
15574cd665 nrf: Add support for time.ticks_xxx functions using RTC1.
This commit adds time.ticks_ms/us support using RTC1 as the timebase.  It
also adds the time.ticks_add/diff helper functions.  This feature can be
enabled using MICROPY_PY_TIME_TICKS.  If disabled the system uses the
legacy sleep methods and does not have any ticks functions.

In addition support for MICROPY_EVENT_POLL_HOOK was added to the
time.sleep_ms(x) function, making this function more power efficient and
allows support for select.poll/asyncio.  To support this, the RTC's CCR0
was used to schedule a ~1msec event to wakeup the CPU.

Some important notes about the RTC timebase:

- Since the granularity of RTC1's ticks are approx 30usec, time.ticks_us is
not perfect, does not have 1us resolution, but is otherwise quite usable.
For tighter measurments the ticker's 1MHz counter should be used.

- time.ticks_ms(x) should *not* be called in an IRQ with higher prio than
the RTC overflow irq (3).  If so it introduces a race condition and
possibly leads to wrong tick calculations.

See #6171 and #6202.
2020-07-08 23:47:02 +10:00
Damien George
69661f3343 all: Reformat C and Python source code with tools/codeformat.py.
This is run with uncrustify 0.70.1, and black 19.10b0.
2020-02-28 10:33:03 +11:00
Damien George
ac8383a95d nrf: Use MICROPY_HW_ENABLE_RNG instead of MICROPY_PY_RANDOM_HW_RNG.
The "random" module no longer uses the hardware RNG (the extmod version of
this module has a pseudo-random number generator), so the config option
MICROPY_PY_RANDOM_HW_RNG is no longer meaningful.  This commit replaces it
with MICROPY_HW_ENABLE_RNG, which controls whether the hardware RNG is
included in the build.
2020-02-18 12:43:16 +11:00
Damien George
6ad3bb1e12 nrf: Remove custom "random" module and use extmod version instead.
Hardware RNG code is moved to drivers/rng.[ch].
2020-02-18 12:43:16 +11:00
Yonatan Goldschmidt
61d2b40ad5 lib/utils/pyexec: Introduce MICROPY_REPL_INFO, wrap debug prints in it.
For the 3 ports that already make use of this feature (stm32, nrf and
teensy) this doesn't make any difference, it just allows to disable it from
now on.

For other ports that use pyexec, this decreases code size because the debug
printing code is dead (it can't be enabled) but the compiler can't deduce
that, so code is still emitted.
2019-12-28 00:05:39 +11:00
Damien George
799b6d1e0c extmod: Consolidate FAT FS config to MICROPY_VFS_FAT across all ports.
This commit removes the Makefile-level MICROPY_FATFS config and moves the
MICROPY_VFS_FAT config to the Makefile level to replace it.  It also moves
the include of the oofatfs source files in the build from each port to a
central place in extmod/extmod.mk.

For a port to enabled VFS FAT support it should now set MICROPY_VFS_FAT=1
at the level of the Makefile.  This will include the relevant oofatfs files
in the build and set MICROPY_VFS_FAT=1 at the C (preprocessor) level.
2019-11-11 11:37:38 +11:00
Damien George
d2384efa80 py: Automatically provide weak links from "foo" to "ufoo" module name.
This commit implements automatic module weak links for all built-in
modules, by searching for "ufoo" in the built-in module list if "foo"
cannot be found.  This means that all modules named "ufoo" are always
available as "foo".  Also, a port can no longer add any other weak links,
which makes strict the definition of a weak link.

It saves some code size (about 100-200 bytes) on ports that previously had
lots of weak links.

Some changes from the previous behaviour:
- It doesn't intern the non-u module names (eg "foo" is not interned),
  which saves code size, but will mean that "import foo" creates a new qstr
  (namely "foo") in RAM (unless the importing module is frozen).
- help('modules') no longer lists non-u module names, only the u-variants;
  this reduces duplication in the help listing.

Weak links are effectively the same as having a set of symbolic links on
the filesystem that is searched last.  So an "import foo" will search
built-in modules first, then all paths in sys.path, then weak links last,
importing "ufoo" if it exists.  Thus a file called "foo.py" somewhere in
sys.path will still have precedence over the weak link of "foo" to "ufoo".

See issues: #1740, #4449, #5229, #5241.
2019-10-22 15:30:52 +11:00
Damien George
50d5114fcd nrf/mpconfigport.h: Enable MICROPY_KBD_EXCEPTION by default. 2019-05-22 12:47:48 +10:00