diff --git a/sim/FreeRTOS.cpp b/sim/FreeRTOS.cpp
index d64e194..5647495 100644
--- a/sim/FreeRTOS.cpp
+++ b/sim/FreeRTOS.cpp
@@ -36,6 +36,10 @@ void vPortFree( void *pv ) {
   return free(pv);
 }
 
+size_t xPortGetHeapSize(void) {
+  return configTOTAL_HEAP_SIZE;
+}
+
 size_t xPortGetFreeHeapSize(void) {
   return currentFreeHeap;
 }
diff --git a/sim/FreeRTOS.h b/sim/FreeRTOS.h
index 868ff80..625c53e 100644
--- a/sim/FreeRTOS.h
+++ b/sim/FreeRTOS.h
@@ -86,6 +86,7 @@ void NVIC_SystemReset(void);
 
 #define configTOTAL_HEAP_SIZE                   (1024 * 40)
 
+size_t xPortGetHeapSize(void);
 size_t xPortGetFreeHeapSize(void);
 size_t xPortGetMinimumEverFreeHeapSize(void);