diff --git a/library/aria.c b/library/aria.c
index f6ad7f1..1d1daa1 100644
--- a/library/aria.c
+++ b/library/aria.c
@@ -85,11 +85,33 @@
  * Common compilers fail to translate this to minimal number of instructions,
  * so let's provide asm versions for common platforms with C fallback.
  */
-#if defined(MBEDTLS_HAVE_ASM) && defined(__GNUC__)
-#if defined(__i386__) || defined(__amd64__) || defined( __x86_64__)
+#if defined(MBEDTLS_HAVE_ASM)
+#if defined(__arm__)
+/* armcc5 --gnu defines __GNUC__ but doesn't support GNU's extended asm */
+#if defined(__GNUC__) && \
+    ( !defined(__ARMCC_VERSION) || __ARMCC_VERSION >= 6000000 )
+static inline uint32_t aria_p1( uint32_t x )
+{
+    uint32_t r;
+    asm( "rev16 %0, %1" : "=l" (r) : "l" (x) );
+    return( r );
+}
+#define ARIA_P1 aria_p1
+#elif defined(__ARMCC_VERSION) && __ARMCC_VERSION < 6000000
+static __inline uint32_t aria_p1( uint32_t x )
+{
+    uint32_t r;
+    __asm( "rev16 r, x" );
+    return( r );
+}
+#define ARIA_P1 aria_p1
+#endif
+#endif /* arm */
+#if defined(__GNUC__) && \
+    defined(__i386__) || defined(__amd64__) || defined( __x86_64__)
 /* I couldn't find an Intel equivalent of ret16, so two instructions */
 #define ARIA_P1(x) ARIA_P2( ARIA_P3( x ) )
-#endif
+#endif /* x86 gnuc */
 #endif /* MBEDTLS_HAVE_ASM && GNUC */
 #if !defined(ARIA_P1)
 #define ARIA_P1(x) ((((x) >> 8) & 0x00FF00FF) ^ (((x) & 0x00FF00FF) << 8))
@@ -112,15 +134,37 @@
  * Some compilers fail to translate this to a single instruction,
  * so let's provide asm versions for common platforms with C fallback.
  */
-#if defined(MBEDTLS_HAVE_ASM) && defined(__GNUC__)
-#if defined(__i386__) || defined(__amd64__) || defined( __x86_64__)
+#if defined(MBEDTLS_HAVE_ASM)
+#if defined(__arm__)
+/* armcc5 --gnu defines __GNUC__ but doesn't support GNU's extended asm */
+#if defined(__GNUC__) && \
+    ( !defined(__ARMCC_VERSION) || __ARMCC_VERSION >= 6000000 )
+static inline uint32_t aria_p3( uint32_t x )
+{
+    uint32_t r;
+    asm( "rev %0, %1" : "=l" (r) : "l" (x) );
+    return( r );
+}
+#define ARIA_P3 aria_p3
+#elif defined(__ARMCC_VERSION) && __ARMCC_VERSION < 6000000
+static __inline uint32_t aria_p3( uint32_t x )
+{
+    uint32_t r;
+    __asm( "rev r, x" );
+    return( r );
+}
+#define ARIA_P3 aria_p3
+#endif
+#endif /* arm */
+#if defined(__GNUC__) && \
+    defined(__i386__) || defined(__amd64__) || defined( __x86_64__)
 static inline uint32_t aria_p3( uint32_t x )
 {
     asm( "bswap %0" : "=r" (x) : "0" (x) );
     return( x );
 }
 #define ARIA_P3 aria_p3
-#endif
+#endif /* x86 gnuc */
 #endif /* MBEDTLS_HAVE_ASM && GNUC */
 #if !defined(ARIA_P3)
 #define ARIA_P3(x) ARIA_P2( ARIA_P1 ( x ) )