GCC 9 and sufficiently-new Clang (including ARM Compiler 6.13) give us
access to the C++20 (draft) `is_constant_evaluated` test. Allows us to
restrict code to compile-time only.
This is particularly useful when using assembler intrinsics, which the
compiler cannot optimise or compile-time evaluate. It allows us to write
something like
constexpr uint32_t reverse_bits(uint32_t x)
{
if (is_constant_evaluated(x)) {
// C code to do calculation here
return x;
} else {
// an assembler intrinsic that cannot be optimised
return __RBIT(x);
}
}
This can then be totally compile-time given a constant input.
(In this example, ultimately it would be a good idea to include this
functionality in CMSIS's GCC `__RBIT`, which needs it because GCC
requires use of assembler. Clang implements `__RBIT` as a built-in,
meaning it can already compute it at compile-time, so does not benefit.).
- By default, Mbed OS build tools use standard C library for all supported toolchains.
It is possible to use smaller C libraries by overriding the "target.default_lib" option
with "small". This option is only currently supported for the GCC_ARM toolchain.
This override config option is now extended in the build tool for ARM toolchain.
- Add configuration option to specify libraries supported for each toolchain per targets.
- Move __aeabi_assert function from rtos to retarget code so it’s available for bare metal.
- Use 2 memory region model for ARM toolchain scatter file for the following targets:
NUCLEO_F207ZG, STM32F411xE, STM32F429xI, NUCLEO_L073RZ, STM32F303xE
- Add a warning message in the build tools to deprecate uARM toolchain.
- NewLib-Nano C library is not supporting floating-point and printf with %hhd,%hhu,%hhX,%lld,%llu,%llX
format specifier so skipping those green tea test cases.
* Deprecate RawSerial.
* Introduce UnbufferedSerial to provide unbuffered I/O by implementing
with a FileHandle interface for I/O streams.
* Add Greentea test for the UnbufferedSerial class.
Added missing mbed_error_initialize function call in bare metal boot code which is used
to retrieve the crash report from RAM in case of any previous abnormal re-boot but this function call is present in RTOS boot code.
For consistency with `std::shared_ptr`, and `mbed::Callback`, and as a
potential optimisation aid, give `SharedPtr` a distinct constructor for
`nullptr`.
* Make mbed_error use bitwise MbedCRC call rather than local
implementation.
* Remove use of POLY_32BIT_REV_ANSI from LittleFS.
* Move some MbedCRC instances closer to use - construction cost is
trivial, and visibility aids compiler optimisation.
If the fault handler was hit before the stdio console was used and
initialised, the initialisation code caused a "mutex in ISR" trap,
stopping the register dump from happening.
Temporarily set the `error_in_progress` flag at the top of the fault
handler, and restore it before calling `mbed_error`. Take the
opportunity to suppress fault dumps on recursive crashes, much as is
done inside `mbed_error`.
Build successfully when `platform.stdio-convert-tty-newlines` or
`platform.stdio-convert-newlines` are set to `true` by ensuring
`isatty()` is also included when `platform.stdio-minimal-console-only`
is set to `true`.
* Make mbed_error use bitwise MbedCRC call rather than local
implementation.
* Remove use of POLY_32BIT_REV_ANSI from LittleFS.
* Move some MbedCRC instances closer to use - construction cost is
trivial, and visibility aids compiler optimisation.
The retarget code allocates an array of FileHandle* for console and file
handling (filehandles). A tiny target only needs a console (putc/getc).
There is no need for file handling.
The POSIX layer and the array of FileHandle* is not required for small
targets that only need a console ; this code is optionally compiled
out if the configuration parameter platform.stdio-minimal-console-only is
set to `"true"`.
Kevin Bracey
Martin Kojtal
Hugues Kamba
Heath Petersen
Rajkumar Kanagaraj
Anna Bridge
Antti Kauppila
Filip Jagodzinski
Przemyslaw Stekiel
Philipp Steiner
Marcin Tomczyk