diff options
Diffstat (limited to 'StdLib/LibC/Main/bswap64.c')
-rw-r--r-- | StdLib/LibC/Main/bswap64.c | 44 |
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
+}
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