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-rw-r--r--src/util/bitscan.c80
1 files changed, 80 insertions, 0 deletions
diff --git a/src/util/bitscan.c b/src/util/bitscan.c
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+++ b/src/util/bitscan.c
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+/**************************************************************************
+ *
+ * Copyright 2008 VMware, Inc.
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+
+#include "bitscan.h"
+
+#ifdef HAVE___BUILTIN_FFS
+#elif defined(_MSC_VER) && (_M_IX86 || _M_ARM || _M_AMD64 || _M_IA64)
+#else
+int
+ffs(unsigned i)
+{
+ int bit = 0;
+ if (!i)
+ return bit;
+ if (!(i & 0xffff)) {
+ bit += 16;
+ i >>= 16;
+ }
+ if (!(i & 0xff)) {
+ bit += 8;
+ i >>= 8;
+ }
+ if (!(i & 0xf)) {
+ bit += 4;
+ i >>= 4;
+ }
+ if (!(i & 0x3)) {
+ bit += 2;
+ i >>= 2;
+ }
+ if (!(i & 0x1))
+ bit += 1;
+ return bit + 1;
+}
+#endif
+
+#ifdef HAVE___BUILTIN_FFSLL
+#elif defined(_MSC_VER) && (_M_AMD64 || _M_ARM || _M_IA64)
+#else
+int
+ffsll(uint64_t val)
+{
+ int bit;
+
+ bit = ffs((unsigned) (val & 0xffffffff));
+ if (bit != 0)
+ return bit;
+
+ bit = ffs((unsigned) (val >> 32));
+ if (bit != 0)
+ return 32 + bit;
+
+ return 0;
+}
+#endif