mesa/gallium: Move u_bit_scan{,64} from gallium to util.
[mesa.git] / src / util / bitscan.c
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,
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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.
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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
34 int
35 ffs(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
65 int
66 ffsll(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