Support bare-metal build for NXP LPC1114

Author: toyowata

targets/TARGET_NXP/TARGET_LPC11XX_11CXX/device/TOOLCHAIN_GCC_ARM/startup_LPC11xx.S

@@ -44,36 +44,7 @@
    aborting compilation, it is not the run time limit:
    Heap_Size + Stack_Size = 0x80 + 0x80 = 0x100
  */
-    .section .stack
-    .align 3
-#ifdef __STACK_SIZE
-    .equ    Stack_Size, __STACK_SIZE
-#else
-    .equ    Stack_Size, 0x80
-#endif
-    .globl    __StackTop
-    .globl    __StackLimit
-__StackLimit:
-    .space    Stack_Size
-    .size __StackLimit, . - __StackLimit
-__StackTop:
-    .size __StackTop, . - __StackTop
 
-    .section .heap
-    .align 3
-#ifdef __HEAP_SIZE
-    .equ    Heap_Size, __HEAP_SIZE
-#else
-    .equ    Heap_Size, 0x80
-#endif
-    .globl    __HeapBase
-    .globl    __HeapLimit
-__HeapBase:
-    .space    Heap_Size
-    .size __HeapBase, . - __HeapBase
-__HeapLimit:
-    .size __HeapLimit, . - __HeapLimit
-    
     .section .isr_vector
     .align 2
     .globl __isr_vector

targets/TARGET_NXP/TARGET_LPC11XX_11CXX/device/cmsis_nvic.c

@@ -60,8 +60,9 @@ void NVIC_SetVector(IRQn_Type IRQn, uint32_t vector) {
     static volatile uint32_t* vectors = (uint32_t*)NVIC_RAM_VECTOR_ADDRESS;
 
     // Copy and switch to dynamic vectors if first time called
-    if((LPC_SYSCON->SYSMEMREMAP & 0x3) != 0x1) {     
-      uint32_t *old_vectors = (uint32_t *)0;         // FLASH vectors are at 0x0
+    if((LPC_SYSCON->SYSMEMREMAP & 0x3) != 0x1) {
+      // Add volatile qualifier to avoid armclang aggressive optimization
+      volatile uint32_t *old_vectors = (uint32_t *)0;         // FLASH vectors are at 0x0
       for(i = 0; i < NVIC_NUM_VECTORS; i++) {    
             vectors[i] = old_vectors[i];
         }

targets/targets.json

@@ -334,9 +334,27 @@
             "SLEEP",
             "SPI",
             "SPISLAVE",
-            "STDIO_MESSAGES"
+            "STDIO_MESSAGES",
+            "USTICKER"
         ],
-        "default_lib": "small",
+        "overrides": {
+            "tickless-from-us-ticker": true,
+            "boot-stack-size": "0x400"
+        },
+        "supported_c_libs": {
+            "arm": [
+                "std",
+                "small"
+            ],
+            "gcc_arm": [
+                "std",
+                "small"
+            ],
+            "iar": [
+                "std"
+            ]
+        },
+        "c_lib": "small",
         "release_versions": [
             "2"
         ],