1/**************************************************************************
2 *
3 * Copyright 2008 VMware, Inc.
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
22 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27
28
29#include "bitscan.h"
30
31#ifdef HAVE___BUILTIN_FFS
32#elif defined(_MSC_VER) && (_M_IX86 || _M_ARM || _M_AMD64 || _M_IA64)
33#else
34int
35ffs(unsigned i)
36{
37   int bit = 0;
38   if (!i)
39      return bit;
40   if (!(i & 0xffff)) {
41      bit += 16;
42      i >>= 16;
43   }
44   if (!(i & 0xff)) {
45      bit += 8;
46      i >>= 8;
47   }
48   if (!(i & 0xf)) {
49      bit += 4;
50      i >>= 4;
51   }
52   if (!(i & 0x3)) {
53      bit += 2;
54      i >>= 2;
55   }
56   if (!(i & 0x1))
57      bit += 1;
58   return bit + 1;
59}
60#endif
61
62#ifdef HAVE___BUILTIN_FFSLL
63#elif defined(_MSC_VER) && (_M_AMD64 || _M_ARM || _M_IA64)
64#else
65int
66ffsll(uint64_t val)
67{
68   int bit;
69
70   bit = ffs((unsigned) (val & 0xffffffff));
71   if (bit != 0)
72      return bit;
73
74   bit = ffs((unsigned) (val >> 32));
75   if (bit != 0)
76      return 32 + bit;
77
78   return 0;
79}
80#endif
81