newlib: implement __atomic_load/__atomic_store functions

components/newlib/stdatomic.c

@@ -9,6 +9,7 @@
 #include "sdkconfig.h"
 #include <stdbool.h>
 #include <stdint.h>
+#include <string.h>
 #include "soc/soc_caps.h"
 #include "freertos/FreeRTOS.h"
 
@@ -494,3 +495,18 @@ ATOMIC_LOAD(8, long long unsigned int)
 ATOMIC_STORE(8, long long unsigned int)
 
 #endif // !HAS_ATOMICS_64
+
+// Clang generates calls to the __atomic_load/__atomic_store functions for object size more then 4 bytes
+void CLANG_ATOMIC_SUFFIX( __atomic_load ) (int size, void *src, void *dest, int model) {
+    unsigned state = _ATOMIC_ENTER_CRITICAL();
+    memcpy(dest, src, size);
+    _ATOMIC_EXIT_CRITICAL(state);
+}
+CLANG_DECLARE_ALIAS( __atomic_load )
+
+void CLANG_ATOMIC_SUFFIX( __atomic_store ) (int size, void *dest, void *src, int model) {
+    unsigned state = _ATOMIC_ENTER_CRITICAL();
+    memcpy(dest, src, size);
+    _ATOMIC_EXIT_CRITICAL(state);
+}
+CLANG_DECLARE_ALIAS( __atomic_store)