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Merge pull request #10934 from gschorcht/cpu_atmega_common_heap

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cpu/atmega_common: make remaining RAM available as heap
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Sebastian Meiling 2019-04-15 13:17:57 +02:00 committed by GitHub
commit d08a6132bf
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1 changed files with 19 additions and 0 deletions
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19
cpu/atmega_common/thread_arch.c
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@ -203,6 +203,12 @@ void cpu_switch_context_exit(void)
__enter_thread_mode();
}
#define STACK_POINTER ((char *)AVR_STACK_POINTER_REG)
extern size_t __malloc_margin;
extern char * __malloc_heap_start;
extern char * __malloc_heap_end;
extern char *__brkval;
/**
* @brief Set the MCU into Thread-Mode and load the initial task from the stack and run it
*/
@ -210,6 +216,19 @@ void NORETURN __enter_thread_mode(void) __attribute__((naked));
void NORETURN __enter_thread_mode(void)
{
irq_enable();
/*
* Save the current stack pointer to __malloc_heap_end. Since
* context_restore is always inline, there is no function call and the
* current stack pointer is the lowest possible stack address outside the
* thread-mode. Therefore, it can be considered as the top of the heap.
*/
__malloc_heap_end = STACK_POINTER - __malloc_margin;
/* __brkval has to be initialized if necessary */
if (__brkval == NULL) {
__brkval = __malloc_heap_start;
}
__context_restore();
__asm__ volatile ("ret");