Posted on July 07, 2015 at 22:32
I'm using FreeRTOS on STM32F4 with ARM-GCC and i need to do some interrupt/task protection for a simple flag checking and clearing function. Here's an example:
int
flag;
// Some code sets flag to 1 sometimes
int
checkFlagOnce(
void
)
{
int
status = 0;
if
(osMutexWait(Mutex, osWaitForever) == osOK)
{
status = flag;
flag = 0;
(
void
)osMutexRelease(Mutex);
}
return
status;
}
However the mutex code seems to be bit of an overkill. So i was thinking if the Cortex M4 has some special instruction (and ARM-GCC has a intrinsic function) which reads/checks and clears memory atomically?
I checked the instruction set at ARM site but i couldn't find anything like that so i'm double checking.
Or does somebody have a better idea how this could be done fast and simple?
...except global interrupts disabling/enabling.
#cortex-instruction
