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Optimize _sbrk_r when no increment is needed #14

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Optimize _sbrk_r when no increment is needed #14

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6 changes: 5 additions & 1 deletion heap_useNewlib_NXP.c
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Original file line number Diff line number Diff line change
Expand Up @@ -140,6 +140,11 @@ static int heapBytesRemaining = (int)&HEAP_SIZE; // that's (&__HeapLimit)-(&__He
//! _sbrk_r version supporting reentrant newlib (depends upon above symbols defined by linker control file).
void * _sbrk_r(struct _reent *pReent, int incr) {
static char *currentHeapEnd = &__HeapBase;
char *previousHeapEnd = currentHeapEnd;
if(0 == incr) {
// don't suspend all tasks if nothing has to change
return (char *) previousHeapEnd;
}
vTaskSuspendAll(); // Note: safe to use before FreeRTOS scheduler started, but not within an ISR
if (currentHeapEnd + incr > &__HeapLimit) {
// Ooops, no more memory available...
Expand All @@ -159,7 +164,6 @@ void * _sbrk_r(struct _reent *pReent, int incr) {
return (char *)-1; // the malloc-family routine that called sbrk will return 0
}
// 'incr' of memory is available: update accounting and return it.
char *previousHeapEnd = currentHeapEnd;
currentHeapEnd += incr;
heapBytesRemaining -= incr;
#ifndef NDEBUG
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6 changes: 5 additions & 1 deletion heap_useNewlib_ST.c
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Original file line number Diff line number Diff line change
Expand Up @@ -169,6 +169,11 @@ void * _sbrk_r(struct _reent *pReent, int incr) {
char* limit = (xTaskGetSchedulerState()==taskSCHEDULER_NOT_STARTED) ?
stack_ptr : // Before scheduler is started, limit is stack pointer (risky!)
&__HeapLimit-ISR_STACK_LENGTH_BYTES; // Once running, OK to reuse all remaining RAM except ISR stack (MSP) stack
char *previousHeapEnd = currentHeapEnd;
if(0 == incr) {
// don't go into a critical section if nothing has to change
return (char *) previousHeapEnd;
}
DRN_ENTER_CRITICAL_SECTION(usis);
if (currentHeapEnd + incr > limit) {
// Ooops, no more memory available...
Expand All @@ -190,7 +195,6 @@ void * _sbrk_r(struct _reent *pReent, int incr) {
return (char *)-1; // the malloc-family routine that called sbrk will return 0
}
// 'incr' of memory is available: update accounting and return it.
char *previousHeapEnd = currentHeapEnd;
currentHeapEnd += incr;
heapBytesRemaining -= incr;
#ifndef NDEBUG
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