In this unusual case, (len + 1) is zero, the allocation in vstr_init
succeeds (allocating 1 byte), and then the caller is likely to erroneously
access outside the allocated region, for instance with a memset().
This could be triggered with os.urandom(-1) after it was converted to use
mp_obj_new_bytes_of_zeros.
PacketBuffer facilitates packet oriented BLE protocols such as BLE
MIDI and the Apple Media Service.
This also adds PHY, MTU and connection event extension negotiation
to speed up data transfer when possible.
By having an order-only dependency on the directory itself, the directory
is sure to be created before the rule to create a .mo file is.
This fixes a low-freqency error on github actions such as
> msgfmt: error while opening "build/genhdr/en_US.mo" for writing: No such file or directory
These s16-s21 registers are used by gcc so need to be saved. Future
versions of gcc (beyond v9.1.0), or other compilers, may eventually need
additional registers saved/restored.
See issue #4844.
Recent versions of gcc perform optimisations which can lead to the
following code from the MP_NLR_JUMP_HEAD macro being omitted:
top->ret_val = val; \
MP_NLR_RESTORE_PYSTACK(top); \
*_top_ptr = top->prev; \
This is noticeable (at least) in the unix coverage on x86-64 built with gcc
9.1.0. This is because the nlr_jump function is marked as no-return, so
gcc deduces that the above code has no effect.
Adding MP_UNREACHABLE tells the compiler that the asm code may branch
elsewhere, and so it cannot optimise away the code.
Protocols are nice, but there is no way for C code to verify whether
a type's "protocol" structure actually implements some particular
protocol. As a result, you can pass an object that implements the
"vfs" protocol to one that expects the "stream" protocol, and the
opposite of awesomeness ensues.
This patch adds an OPTIONAL (but enabled by default) protocol identifier
as the first member of any protocol structure. This identifier is
simply a unique QSTR chosen by the protocol designer and used by each
protocol implementer. When checking for protocol support, instead of
just checking whether the object's type has a non-NULL protocol field,
use `mp_proto_get` which implements the protocol check when possible.
The existing protocols are now named:
protocol_framebuf
protocol_i2c
protocol_pin
protocol_stream
protocol_spi
protocol_vfs
(most of these are unused in CP and are just inherited from MP; vfs and
stream are definitely used though)
I did not find any crashing examples, but here's one to give a flavor of what
is improved, using `micropython_coverage`. Before the change,
the vfs "ioctl" protocol is invoked, and the result is not intelligible
as json (but it could have resulted in a hard fault, potentially):
>>> import uos, ujson
>>> u = uos.VfsPosix('/tmp')
>>> ujson.load(u)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ValueError: syntax error in JSON
After the change, the vfs object is correctly detected as not supporting
the stream protocol:
>>> ujson.load(p)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
OSError: stream operation not supported
If a translation only has unicode code points 255 and below, the "values"
array can be 8 bits instead of 16 bits. This reclaims some code size,
e.g., in a local build, trinket_m0 / en_US reclaimed 112 bytes and de_DE
reclaimed 104 bytes. However, languages like zh_Latn_pinyin, which use
code points above 255, did not benefit.
By treating each unicode code-point as a single entity for huffman
compression, the overall compression rate can be somewhat improved
without changing the algorithm. On the decompression side, when
compressed values above 127 are encountered, they need to be
converted from a 16-bit Unicode code point into a UTF-8 byte
sequence.
Doing this returns approximately 1.5kB of flash storage with the
zh_Latn_pinyin translation. (292 -> 1768 bytes remaining in my build
of trinket_m0)
Other "more ASCII" translations benefit less, and in fact
zh_Latn_pinyin is no longer the most constrained translation!
(de_DE 1156 -> 1384 bytes free in flash, I didn't check others
before pushing for CI)
English is slightly pessimized, 2840 -> 2788 bytes, probably mostly
because the "values" array was changed from uint8_t to uint16_t,
which is strictly not required for an all-ASCII translation. This
could probably be avoided in this case, but as English is not the
most constrained translation it doesn't really matter.
Testing performed: built for feather nRF52840 express and trinket m0
in English and zh_Latn_pinyin; ran and verified the localized
messages such as
Àn xià rènhé jiàn jìnrù REPL. Shǐyòng CTRL-D chóngxīn jiāzài.
and
Press any key to enter the REPL. Use CTRL-D to reload.
were properly displayed.
When adding the ability for boards to turn on the `@micropython.native`, `viper`, and `asm_thumb` decorators it was pointed out that it's somewhat awkward to write libraries and drivers that can take advantage of this since the decorators raise `SyntaxErrors` if they aren't enabled. In the case of `viper` and `asm_thumb` this behavior makes sense as they require writing non-normative code. Drivers could have a normal and viper/thumb implementation and implement them as such:
```python
try:
import _viper_impl as _impl
except SyntaxError:
import _python_impl as _impl
def do_thing():
return _impl.do_thing()
```
For `native`, however, this behavior and the pattern to work around it is less than ideal. Since `native` code should also be valid Python code (although not necessarily the other way around) using the pattern above means *duplicating* the Python implementation and adding `@micropython.native` in the code. This is an unnecessary maintenance burden.
This commit *modifies* the behavior of the `@micropython.native` decorator. On boards with `CIRCUITPY_ENABLE_MPY_NATIVE` turned on it operates as usual. On boards with it turned off it does *nothing*- it doesn't raise a `SyntaxError` and doesn't apply optimizations. This means we can write our drivers/libraries once and take advantage of speedups on boards where they are enabled.
This improves performance of running python code by 34%, based
on the "pystone" benchmark on metro m4 express at 5000 passes
(1127.65 -> 1521.6 passes/second).
In addition, by instrumenting the tick function and monitoring on an
oscilloscope, the time actually spent in run_background_tasks() on
the metro m4 decreases from average 43% to 0.5%. (however, there's
some additional overhead that is moved around and not accounted for
in that "0.5%" figure, each time supervisor_run_background_tasks_if_tick
is called but no tick has occurred)
On the CPB, it increases pystone from 633 to 769, a smaller percentage
increase of 21%. I did not measure the time actually spent in
run_background_tasks() on CPB.
Testing performed: on metro m4 and cpb, run pystone adapted from python3.4
(change time.time to time.monotonic for sub-second resolution)
Besides running a 5000 pass test, I also ran a 50-pass test while
scoping how long an output pin was set. Average: 34.59ms or 1445/s on m4,
67.61ms or 739/s on cbp, both matching the other pystone result reasonably
well.
import pystone
import board
import digitalio
import time
d = digitalio.DigitalInOut(board.D13)
d.direction = digitalio.Direction.OUTPUT
while True:
d.value = 0
time.sleep(.01)
d.value = 1
pystone.main(50)
This code is shared by most parts, except where not all the #ifdefs
inside the tick function were present in all ports. This mostly would
have broken gamepad tick support on non-samd ports.
The "ms32" and "ms64" variants of the tick functions are introduced
because there is no 64-bit atomic read. Disabling interrupts avoids
a low probability bug where milliseconds could be off by ~49.5 days
once every ~49.5 days (2^32 ms).
Avoiding disabling interrupts when only the low 32 bits are needed is a minor
optimization.
Testing performed: on metro m4 express, USB still works and
time.monotonic_ns() still counts up
To benefit from gcc's "once-only headers" implementation, the
"wrapper-#ifndef" must be the first non-comment part of the file,
according to the manual for various gcc/cpp versions.
This PR refines the _bleio API. It was originally motivated by
the addition of a new CircuitPython service that enables reading
and modifying files on the device. Moving the BLE lifecycle outside
of the VM motivated a number of changes to remove heap allocations
in some APIs.
It also motivated unifying connection initiation to the Adapter class
rather than the Central and Peripheral classes which have been removed.
Adapter now handles the GAP portion of BLE including advertising, which
has moved but is largely unchanged, and scanning, which has been enhanced
to return an iterator of filtered results.
Once a connection is created (either by us (aka Central) or a remote
device (aka Peripheral)) it is represented by a new Connection class.
This class knows the current connection state and can discover and
instantiate remote Services along with their Characteristics and
Descriptors.
Relates to #586
If kw_args is NULL then memcpy() gets a NULL source argument.
This is undefined behavior under the C standard, even if 0 bytes
are being copied.
This problem was found using clang 7's scan-build static analyzer.
Left shift of negative numbers is undefined in the "C" standard. Multiplying
by 128 has the intended effect (in the absence of integer overflow, anyway),
can be implemented using the same shift instruction, but does not invoke
undefined behavior.
This problem was found using clang 7's scan-build static analyzer.
The remaining assignment was added in upstream micropython; the
deleted assignment was added in circuitpython as part of the long-lived
object area feature. During the merge, the redundant assignment
was not removed.
(since collected is a local variable and no pointers to it escape,
it doesn't seem possible for the placement of the assignment before
or after GC_ENTER() is important)
This diagnostic was found by clang 7's scan-build static analyzer.
Left shift of negative numbers is undefined in the "C" standard. Multiplying
by 256 has the intended effect (in the absence of integer overflow, anyway),
can be implemented using the same shift instruction, but does not invoke
undefined behavior.
This problem was found using clang 7's scan-build static analyzer.
While finding sources of clicks and buzzes in nrf i2sout, I identified
this site as one which could be long running. Reproducer code was to
play a 22.05kHz sample and repeatedly print `os.listdir('')`
While finding sources of clicks and buzzes in nrf i2sout, I identified
this site as one which could be long running. Reproducer code was to
play a 22.05kHz sample and repeatedly print `os.listdir('')`
Scott Shawcroft
Dan Halbert
Steve Theodore
Roy Hooper
Hierophect
Jeff Epler
Scott Shawcroft
Marius-450
Damien George
Thea Flowers
David Grimes
Jerry Needell
sommersoft