1 files changed, 44 insertions, 0 deletions
diff --git a/StdLib/LibC/Main/bswap64.c b/StdLib/LibC/Main/bswap64.c
new file mode 100644
index 0000000000..29e6916ea6
--- /dev/null
+++ b/StdLib/LibC/Main/bswap64.c
@@ -0,0 +1,44 @@
+/*  $NetBSD: bswap64.c,v 1.1 2005/12/20 19:28:51 christos Exp $    */
+
+/*
+ * Written by Manuel Bouyer <bouyer@NetBSD.org>.
+ * Public domain.
+ */
+
+//#include <sys/cdefs.h>
+//#if defined(LIBC_SCCS) && !defined(lint)
+//__RCSID("$NetBSD: bswap64.c,v 1.1 2005/12/20 19:28:51 christos Exp $");
+//#endif /* LIBC_SCCS and not lint */
+
+//#include <sys/types.h>
+//#include <machine/bswap.h>
+
+#undef bswap64
+
+UINT64
+bswap64(UINT64 x)
+{
+#ifndef _LP64
+  /*
+   * Assume we have wide enough registers to do it without touching
+   * memory.
+   */
+  return  ( (x << 56) & 0xff00000000000000UL ) |
+    ( (x << 40) & 0x00ff000000000000UL ) |
+    ( (x << 24) & 0x0000ff0000000000UL ) |
+    ( (x <<  8) & 0x000000ff00000000UL ) |
+    ( (x >>  8) & 0x00000000ff000000UL ) |
+    ( (x >> 24) & 0x0000000000ff0000UL ) |
+    ( (x >> 40) & 0x000000000000ff00UL ) |
+    ( (x >> 56) & 0x00000000000000ffUL );
+#else
+  /*
+   * Split the operation in two 32bit steps.
+   */
+  u_int32_t tl, th;
+
+  th = bswap32((u_int32_t)(x & 0x00000000ffffffffULL));
+  tl = bswap32((u_int32_t)((x >> 32) & 0x00000000ffffffffULL));
+  return ((u_int64_t)th << 32) | tl;
+#endif
+}