Directly inline x86-64 asm into bswap.h

1 files changed, 12 insertions, 2 deletions

diff --git a/src/utils/bswap.h b/src/utils/bswap.h
index e38d3c6fa..8fb5ed12f 100644
--- a/src/utils/bswap.h
+++ b/src/utils/bswap.h
@@ -3,8 +3,8 @@
 * (C) 1999-2008 Jack Lloyd                       *
 *************************************************/
 
-#ifndef BOTAN_BSWAP_H__
-#define BOTAN_BSWAP_H__
+#ifndef BOTAN_BYTE_SWAP_H__
+#define BOTAN_BYTE_SWAP_H__
 
 #include <botan/types.h>
 #include <botan/rotate.h>
@@ -21,17 +21,27 @@ inline u16bit reverse_bytes(u16bit input)
 
 inline u32bit reverse_bytes(u32bit input)
    {
+#if defined(BOTAN_TARGET_ARCH_IS_AMD64)
+   asm("bswapl %0" : "=r" (input) : "0" (input));
+   return input;
+#else
    input = ((input & 0xFF00FF00) >> 8) | ((input & 0x00FF00FF) << 8);
    return rotate_left(input, 16);
+#endif
    }
 
 inline u64bit reverse_bytes(u64bit input)
    {
+#if defined(BOTAN_TARGET_ARCH_IS_AMD64)
+   asm("bswapq %0" : "=r" (input) : "0" (input));
+   return input;
+#else
    u32bit hi = ((input >> 40) & 0x00FF00FF) | ((input >> 24) & 0xFF00FF00);
    u32bit lo = ((input & 0xFF00FF00) >> 8) | ((input & 0x00FF00FF) << 8);
    hi = (hi << 16) | (hi >> 16);
    lo = (lo << 16) | (lo >> 16);
    return (static_cast<u64bit>(lo) << 32) | hi;
+#endif
    }
 
 }