diff --git a/misc.h b/misc.h
index d6cd4212..28f2e972 100644
--- a/misc.h
+++ b/misc.h
@@ -1775,10 +1775,7 @@ inline byte ByteReverse(byte value)
 //! \details ByteReverse calls bswap if available. Otherwise the function performs a 8-bit rotate on the word16
 inline word16 ByteReverse(word16 value)
 {
-#if defined(CRYPTOPP_X86_ASM_AVAILABLE) && defined(CRYPTOPP_MOVBE_AVAILABLE)
-	__asm__ ("movbe %1, %0" : "=m" (value) : "q" (value));
-	return value;
-#elif defined(CRYPTOPP_BYTESWAP_AVAILABLE)
+#if defined(CRYPTOPP_BYTESWAP_AVAILABLE)
 	return bswap_16(value);
 #elif (_MSC_VER >= 1400) || (defined(_MSC_VER) && !defined(_DLL))
 	return _byteswap_ushort(value);
@@ -1792,10 +1789,7 @@ inline word16 ByteReverse(word16 value)
 //! \details ByteReverse calls bswap if available. Otherwise the function uses a combination of rotates on the word32
 inline word32 ByteReverse(word32 value)
 {
-#if defined(CRYPTOPP_X86_ASM_AVAILABLE) && defined(CRYPTOPP_MOVBE_AVAILABLE)
-	__asm__ ("movbe %1, %0" : "=m" (value) : "q" (value));
-	return value;
-#elif defined(__GNUC__) && defined(CRYPTOPP_X86_ASM_AVAILABLE)
+#if defined(__GNUC__) && defined(CRYPTOPP_X86_ASM_AVAILABLE)
 	__asm__ ("bswap %0" : "=r" (value) : "0" (value));
 	return value;
 #elif defined(CRYPTOPP_BYTESWAP_AVAILABLE)
@@ -1804,7 +1798,7 @@ inline word32 ByteReverse(word32 value)
 	return (word32)__lwbrx(&value,0);
 #elif (_MSC_VER >= 1400) || (defined(_MSC_VER) && !defined(_DLL))
 	return _byteswap_ulong(value);
-#elif CRYPTOPP_FAST_ROTATE(32)
+#elif CRYPTOPP_FAST_ROTATE(32) && !defined(__xlC__)
 	// 5 instructions with rotate instruction, 9 without
 	return (rotrFixed(value, 8U) & 0xff00ff00) | (rotlFixed(value, 8U) & 0x00ff00ff);
 #else
@@ -1819,10 +1813,7 @@ inline word32 ByteReverse(word32 value)
 //! \details ByteReverse calls bswap if available. Otherwise the function uses a combination of rotates on the word64
 inline word64 ByteReverse(word64 value)
 {
-#if defined(CRYPTOPP_X86_ASM_AVAILABLE) && defined(CRYPTOPP_MOVBE_AVAILABLE) && defined(__x86_64__)
-	__asm__ ("movbe %1, %0" : "=m" (value) : "q" (value));
-	return value;
-#elif defined(__GNUC__) && defined(CRYPTOPP_X86_ASM_AVAILABLE) && defined(__x86_64__)
+#if defined(__GNUC__) && defined(CRYPTOPP_X86_ASM_AVAILABLE) && defined(__x86_64__)
 	__asm__ ("bswap %0" : "=r" (value) : "0" (value));
 	return value;
 #elif defined(CRYPTOPP_BYTESWAP_AVAILABLE)