All Questions
65
questions
2
votes
0
answers
82
views
Embedded C++ - Header-only library optimization level
I mainly develop firmware for ARM Cortex M using gcc and I am migrating from C to C++ and even though I am overall happy with the transition, there are some things that I just can't get right.
...
- 31
0
votes
0
answers
46
views
TensorFlow Lite makefile for Texas Instruments CC1352P7 Board with ARM Cortex M4F multiprotocol
I am trying to use tensorflow lite to deploy a model on MCU Texas Instruments CC1352P7 having
ARM Cortex M4F protocol.
However, when trying to generate the makefile in my command line, I get the ...
- 91
0
votes
1
answer
309
views
Cortex-M4: atomic read and write of uint64_t
I read several times, that Cortex-M4 does not support LDRD/STRD instructions. But when I try with gcc 13.2 I get these instructions. E.g. x3 = x1 for uint64_t gives:
ldrd r2, [r0] @ x1.0_1, ...
- 5,292
1
vote
0
answers
89
views
Cortex-M4: LDRD or VLDR.64 to move uint64_t
The following code produces
volatile uint64_t x1;
volatile uint64_t x3;
int main(){
while(true) {
x3 = x1;
}
}
uses LDRD/STRD to transfer the double word. In outher situations, where ...
- 5,292
2
votes
1
answer
229
views
How to write atomic RMW-sequences on Cortex-M4 in C++
In the following example are 4 versions to atomically increment (or use other form of rmw-statements) on a variable a1 or a2 (depending on the version). The variable a1 or a2 may be shared with some ...
- 5,292
2
votes
2
answers
354
views
Floating point subtraction using sign bit flip and add
Taking double subtraction code from this question Replacing __aeabi_dsub to save space (-flto issues) and adjusting it slightly (both for double and float values):
extern "C" double ...
- 16.1k
0
votes
1
answer
1k
views
Undefined reference to _fini and __dso_handle when compiling c++ for arm cortex M3
I am trying to compile the c++ code for arm cortex-m3. When I use static variable of any class, which has custom destructors (like std::function<> for example), I get the following errors:
/...
- 2,813
0
votes
1
answer
209
views
Casting to double pointer on Arm Cortex-M3
I am using an Arm Cortex-M3 processor. I receive binary data in an unsigned char array, which must be cast into a suitable variable to be used for further computation:
unsigned char gps[24] = { 0xFA, ...
0
votes
2
answers
208
views
Fastest way of resizing (rescaling) a 1D vector by an arbitrary factor
I have the following code that does the resizing of a 1D vector with nearest neighbor interpolation in a similar fashion you'd also resize an image. Another term would be resampling, but there seems ...
- 433
0
votes
0
answers
99
views
Arm Cortex G++ I am writing a edma serial driver for a cortex M7+ I am trying to use c++, want to know if it is possible
I am writing a cortex M7+ edma serial driver. I want to do it in c++ I have it working in c from the examples from the manufacturer. One of the problems I am having a few problems. I know how to call ...
- 29
0
votes
1
answer
395
views
ARM ACLE support in gcc
I'm writing an application where I'd like to detect whether a function is called from an ISR. Ignoring the specifics of the application it is targeting a Cortex M0. In an effort to avoid having to use ...
- 363
0
votes
1
answer
602
views
exceptions not working cross compiling with clang and cmake for arm cortex m4, and "got" section is generated
I have been trying lately to compile firmware with Clang and CMake, using Toolchain files, for C++. I can get it normally working without exceptions. A problem arises when I use exceptions.
LLVM ...
- 606
3
votes
0
answers
272
views
GCC, GDB, and is_stmt
I'm using GNU Arm Embedded Toolchain 10.3 to cross-compile for a Cortex-M0+ target, and using the accompanying GDB to debug.
I want to set a breakpoint on the following line of code:
if (...
- 5,231
15
votes
5
answers
2k
views
Dynamic memory allocation in STD
Working a lot with microcontrollers and C++ it is important for me to know that I do not perform dynamic memory allocations. However I would like to get the most out of the STD lib. What would be the ...
- 1,510
1
vote
2
answers
1k
views
How to create C++ task class (a worker) with Keil's CMSIS RTOS2 thread and timer C funtions?
How do I map C++ class concept to C functions osTimerNew() and osThreadNew() ?
How to use a C++ member function as a Keil RTOS2 osTimerNew() and osThreadNew() callback implementation.
Thanks
- 502