Querying free heap memory

Now that we’ve got functions like uxTaskGetStackHighWaterMark for helping us to fine tune the stack sizes, it would be nice to have a function that returns the available heap memory as well. It’s presently just guess work unless we patch heap_1.c (or whatever) to find out how much memory has actually been allocated.

Querying free heap memory

This could be done through some more hook macros that allow you to track the amount of heap taken and returned. I think this was suggested on this forum before. It would not tell you anything about heap fragmentation though.

Querying free heap memory

Use this function to walk the heap.  It also shows free ROM and RAM.  It’s written for the STR750 with a version 4 IAR compiler. #pragma segment = "ROM0_START" #pragma segment = "ROM0_TOP" #pragma segment = "ROM0_END" #pragma segment = "RAM_START" #pragma segment = "RAM_TOP" #pragma segment = "RAM_END" #pragma segment = "HEAP" typedef struct FREE FREE; struct FREE {                          // Heap free block list structure:    uint32_t sulSize;                   //    Free block size    FREE *spsNext;                      //    Pointer to the next free block }; extern FREE __data_Aldata;             // Heap information structure void ShowHeap (void) {    FREE *xpsFree;                      // Free heap block    long *xplStack;                     // Stack pointer    long xlRomSize;                     // ROM size    long xlRamSize;                     // RAM size    long xlMemory;    long xlHeapTotal;    long xlHeapFree;    long xlHeapUsed; // The heap is walked to find the amount of free memory available.    xlHeapFree = 0;    xpsFree = &__data_Aldata;    while (xpsFree->spsNext) {       xpsFree = xpsFree->spsNext;       xlHeapFree += xpsFree->sulSize;    }    xlHeapTotal = (long) __sfe ("HEAP") – (long) __sfb ("HEAP");    xlHeapUsed = xlHeapTotal – xlHeapFree; // Header    printf ("Heap             | Free stack         | Free memoryrn");    xlRomSize = (long) __sfb ("ROM0_END") – (long) __sfb ("ROM0_START") + 1;    xlRamSize = (long) __sfb ("RAM_END") – (long) __sfb ("RAM_START") + 1; // Used heap, FIQ stack, and free flash    for (xplStack = (long *) &Stack_FIQ;          xplStack < (long *) &StackTop_FIQ && *xplStack == RAM_TEST;          ++xplStack);    xlMemory = (long) __sfb ("ROM0_END") – (long) __sfb ("ROM0_TOP") + 1;    printf ("   Used:  %5d  |    FIQ: %5d      |    Flash:    %6d (%d%%)rn",          xlHeapUsed, 4 * (xplStack – (long *) &Stack_FIQ), xlMemory,          100 * xlMemory / xlRomSize); // Free heap, IRQ stack, and free RAM    for (xplStack = (long *) &Stack_IRQ;          xplStack < (long *) &StackTop_IRQ && *xplStack == RAM_TEST;          ++xplStack);    xlMemory = (int) __sfe ("RAM_END") – (int) __sfb ("RAM_TOP") + 1;    printf ("   Free:  %5d  |    IRQ: %5d      |    RAM:      %6d (%d%%)rn",          xlHeapFree, 4 * (xplStack – (long *) &Stack_IRQ), xlMemory,          100 * xlMemory / xlRamSize); // Total heap, SVC stack, and free heap + RAM    for (xplStack = (long *) &Stack_SVC;          xplStack < (long *) &StackTop_SVC && *xplStack == RAM_TEST;          ++xplStack);    printf ("   TOTAL: %5d  |    SVC: %5d      |    Heap+RAM: %6d (%d%%)rn",          xlHeapTotal, 4 * (xplStack – (long *) &Stack_SVC),          xlMemory + xlHeapFree, 100 * (xlMemory + xlHeapFree) / xlRamSize); }