diff --git a/components/driver/cas.h b/components/driver/cas.h
deleted file mode 100644
index 31a32f1d0c..0000000000
--- a/components/driver/cas.h
+++ /dev/null
@@ -1,23 +0,0 @@
-
-#ifndef __CAS_H__
-#define __CAS_H__
-
-#include "sdkconfig.h"
-#include "freertos/FreeRTOS.h"
-#include "freertos/portmacro.h"
-
-#define __cas_temp_sync_compare_and_swap_test(ptr, expected, desired) ({\
-    bool ret = false;\
-    unsigned state = portENTER_CRITICAL_NESTED(); \
-    if (*ptr == expected) { \
-        *ptr = desired; \
-        ret = true;\
-    }\
-    portEXIT_CRITICAL_NESTED(state); \
-    ret; \
-})
-
-#define __sync_bool_compare_and_swap(ptr, expected, desired) __cas_temp_sync_compare_and_swap_test(ptr, expected, desired)
-
-
-#endif
\ No newline at end of file
diff --git a/components/xtensa/CMakeLists.txt b/components/xtensa/CMakeLists.txt
index 4127650bbd..e44679ebf3 100644
--- a/components/xtensa/CMakeLists.txt
+++ b/components/xtensa/CMakeLists.txt
@@ -3,6 +3,7 @@ if(NOT BOOTLOADER_BUILD)
     if(IDF_TARGET STREQUAL "esp32")
         list(APPEND COMPONENT_SRCS "trax.c")
     endif()
+    list(APPEND COMPONENT_SRCS "stdatomic.c")
 endif()
 
 set(COMPONENT_ADD_INCLUDEDIRS "include" "${IDF_TARGET}/include")
diff --git a/components/xtensa/stdatomic.c b/components/xtensa/stdatomic.c
new file mode 100644
index 0000000000..a4a9c383bf
--- /dev/null
+++ b/components/xtensa/stdatomic.c
@@ -0,0 +1,47 @@
+// Copyright 2015-2019 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//replacement for gcc built-in functions
+
+#include "sdkconfig.h"
+#include "freertos/FreeRTOS.h"
+#include "freertos/portmacro.h"
+#include "xtensa/config/core-isa.h"
+
+
+#define CMP_EXCHANGE(n, type) bool __atomic_compare_exchange_ ## n (type* mem, type* expect, type desired, int success, int failure) \
+{ \
+    bool ret = false; \
+    unsigned state = portENTER_CRITICAL_NESTED(); \
+    if (*mem == *expect) { \
+        ret = true; \
+        *mem = desired; \
+    } else { \
+        *expect = *mem; \
+    } \
+    portEXIT_CRITICAL_NESTED(state); \
+    return ret; \
+}
+
+//this piece of code should only be compiled if the cpu doesn't support atomic compare and swap (s32c1i)
+#if XCHAL_HAVE_S32C1I == 0
+
+#pragma GCC diagnostic ignored "-Wbuiltin-declaration-mismatch"
+
+CMP_EXCHANGE(1, uint8_t)
+CMP_EXCHANGE(2, uint16_t)
+CMP_EXCHANGE(4, uint32_t)
+CMP_EXCHANGE(8, uint64_t)
+
+#endif
\ No newline at end of file