[EFR32] Make RTX using ARMCC aware of reserved stack and heap

Author: stevew817

targets/TARGET_Silicon_Labs/mbed_rtx.h

@@ -23,6 +23,20 @@
 #define OS_CLOCK                  REFERENCE_FREQUENCY
 #endif
 
+#if defined(__CC_ARM)
+extern uint32_t HEAP$$Base;
+extern uint32_t HEAP$$Limit;
+extern uint32_t STACK$$Limit;
+extern uint32_t STACK$$Base;
+#ifndef INITIAL_SP
+#define INITIAL_SP            ((uint32_t)&STACK$$Limit)
+#endif
+#define ISR_STACK_START       ((uint32_t)&STACK$$Base)
+#define ISR_STACK_SIZE        ((uint32_t) ((uint32_t)&STACK$$Limit - (uint32_t)&STACK$$Base))
+#define HEAP_START            ((unsigned char*) ((uint32_t)&HEAP$$Base))
+#define HEAP_SIZE             ((uint32_t) ((uint32_t)&HEAP$$Limit - (uint32_t)&HEAP$$Base))
+#endif
+
 #if defined(TARGET_EFM32GG_STK3700)
 
 #ifndef INITIAL_SP