The standard is 9 years old now, it is well supported in all mayor compilers.
In fact, features of the 'new' standard are already used in RIOT (std_atomic).
Let's make it the default and adapt the Makefiles accordingly.
clang/LLVM is a bit more finicky with what target triples it accepts compared
to GCC. However, the GCC target triple is needed to properly locate the C
libraries. In case a locally installed GCC toolchain uses a technically not
fully correct target triple, it might be impossible to build with LLVM.
The solution here is to allow specifying a TARGET_ARCH_LLVM target triple
(which defaults to TARGET_ARCH), which is passed to clang. For locating the
C lib, still TARGET_ARCH is used.
FEATURES_CONFLICTING previously was declared prior to the function it is
calling, resulting in empty output during the first dependency resolution
iteration. This fixes the order so that the conflicting features are detected
right from the first recursion.
Previously, FEATURES_REQUIRED_ANY didn't honor the order of the alternatives
provided, if none of the features were already in used and multiple options
are provided. This fixes this.
RISC-V support semihosting in very similar way as the cortex-m
microcontrollers. The code calls a breakpoint instruction and the
attached debugger reads/writes registers and memory for stdio.
The RISC-V architecture doesn't support a call number with the EBREAK
instruction, to allow the debugger to detect a semihosting break point,
the EBREAK instruction is wrapped in a SLLI and SRAI instruction. These
use x0 as output register, making them NOP instructions.
One caveat when using this is that the RISC-V core traps the EBREAK
instruction with trap code 3 when no debugger is attached. Restarting
the application with the debugger attached avoids this.
These targets cannot be used in an automated testing workflow without
complex configuration or extend rights.
- Add new 'test-as-root' target for tests that require to be root or
start an external daemon as root
- Add new 'test-with-config' target for tests that require a specific
configuration to succeed (module configuration or hardware
configuration)
This commit makes overflow of signed integers to behave as expected by at 90%
of the C developers, even though overflow of signed integers are strictly
undefined behavior.
Note: Please do not add code relying on a specific behavior for the overflow of
signed integers, even though `-fwrpav` will make that code work. This is
intended to mitigate the risk of bugs in overflow checks being exploited,
not to encourage adding new bugs.
See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=30475 for details and see
http://c-faq.com/misc/intovf.html on how to implement overflow checks properly.
The driver uses the netdev interface. Due to the limited
capabilities of the transceiver (32 byte FIFO and no source address in the layer2 frame),
it relies on 6LowPAN compression and adds the source address to the frame for that.
