Use faster byte swapping when compiling with MSVC

sschuberth · gitster · commit 0fcabdeb52b7 · 2009-10-30T09:37:48.000-07:00
When compiling with MSVC on x86-compatible, use an intrinsic for byte swapping.
In contrast to the GCC path, we do not prefer inline assembly here as it is not
supported for the x64 platform.

Signed-off-by: Sebastian Schuberth &lt;sschuberth@gmail.com&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
diff --git a/compat/bswap.h b/compat/bswap.h
@@ -28,6 +28,16 @@ static inline uint32_t default_swab32(uint32_t val)
 	} \
 	__res; })
 
+#elif defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64))
+
+#include <stdlib.h>
+
+#define bswap32(x) _byteswap_ulong(x)
+
+#endif
+
+#ifdef bswap32
+
 #undef ntohl
 #undef htonl
 #define ntohl(x) bswap32(x)
