src/string/generic/ffsll.c

   1 /*-
   2  * Copyright (c) 1990, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #include <TargetConditionals.h>
  31 #include <sys/cdefs.h>
  32 __FBSDID("$FreeBSD: src/lib/libc/string/ffsll.c,v 1.1 2008/11/03 10:22:19 kib Exp $");
  33
  34 #include <strings.h>
  35
  36 /*
  37  * Find First Set bit
  38  */
  39 int
  40 ffsll(long long mask)
  41 {
  42 #if __has_builtin(__builtin_ffsll)
  43         return __builtin_ffsll(mask);
  44 #elif __has_builtin(__builtin_ctzll)
  45         if (mask == 0)
  46                 return (0);
  47
  48         return __builtin_ctzll(mask) + 1;
  49 #else
  50         int bit;
  51
  52         if (mask == 0)
  53                 return (0);
  54         for (bit = 1; !(mask & 1); bit++)
  55                 mask = (unsigned long long)mask >> 1;
  56         return (bit);
  57 #endif
  58 }
  59
  60 #if VARIANT_DYLD && TARGET_OS_SIMULATOR
  61 int
  62 ffsl(long mask)
  63 {
  64 #if __has_builtin(__builtin_ffsl)
  65         return __builtin_ffsl(mask);
  66 #elif __has_builtin(__builtin_ctzl)
  67         if (mask == 0)
  68                 return (0);
  69
  70         return __builtin_ctzl(mask) + 1;
  71 #else
  72         int bit;
  73
  74         if (mask == 0)
  75                 return (0);
  76         for (bit = 1; !(mask & 1); bit++)
  77                 mask = (unsigned long)mask >> 1;
  78         return (bit);
  79 #endif
  80 }
  81
  82 int
  83 ffs(int mask)
  84 {
  85 #if __has_builtin(__builtin_ffs)
  86         return __builtin_ffs(mask);
  87 #elif __has_builtin(__builtin_ctz)
  88         if (mask == 0)
  89                 return (0);
  90
  91         return __builtin_ctz(mask) + 1;
  92 #else
  93         int bit;
  94
  95         if (mask == 0)
  96                 return (0);
  97         for (bit = 1; !(mask & 1); bit++)
  98                 mask = (unsigned)mask >> 1;
  99         return (bit);
 100 #endif
 101 }
 102 #endif
 103