diff --git a/library/alignment.h b/library/alignment.h
index 86e7821..3c5fa23 100644
--- a/library/alignment.h
+++ b/library/alignment.h
@@ -158,6 +158,11 @@
 #define MBEDTLS_BSWAP64 _byteswap_uint64
 #endif /* defined(_MSC_VER) */
 
+/* Detect armcc built-in byteswap routine */
+#if defined(__ARMCC_VERSION) && (__ARMCC_VERSION >= 410000)
+#define MBEDTLS_BSWAP32 __rev
+#endif
+
 /*
  * Where compiler built-ins are not present, fall back to C code that the
  * compiler may be able to detect and transform into the relevant bswap or