include/ust/processor.h

   1 /* Copyright (C) 2009  Pierre-Marc Fournier
   2  *
   3  * This library is free software; you can redistribute it and/or
   4  * modify it under the terms of the GNU Lesser General Public
   5  * License as published by the Free Software Foundation; either
   6  * version 2.1 of the License, or (at your option) any later version.
   7  *
   8  * This library is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * Lesser General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU Lesser General Public
  14  * License along with this library; if not, write to the Free Software
  15  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
  16  */
  17
  18 #ifndef UST_PROCESSOR_H
  19 #define UST_PROCESSOR_H
  20
  21 #define ____cacheline_aligned __attribute__((aligned(CAA_CACHE_LINE_SIZE)))
  22
  23 #ifdef __i386
  24
  25 static inline int fls(int x)
  26 {
  27         int r;
  28         asm("bsrl %1,%0\n\t"
  29             "cmovzl %2,%0"
  30             : "=&r" (r) : "rm" (x), "rm" (-1));
  31         return r + 1;
  32 }
  33
  34 #elif defined(__x86_64)
  35
  36 static inline int fls(int x)
  37 {
  38         int r;
  39         asm("bsrl %1,%0\n\t"
  40             "cmovzl %2,%0"
  41             : "=&r" (r) : "rm" (x), "rm" (-1));
  42         return r + 1;
  43 }
  44
  45 #elif defined(__PPC__)
  46
  47 static __inline__ int fls(unsigned int x)
  48 {
  49         int lz;
  50
  51         asm ("cntlzw %0,%1" : "=r" (lz) : "r" (x));
  52         return 32 - lz;
  53 }
  54
  55 #else /* arch-agnostic */
  56
  57 static __inline__ int fls(unsigned int x)
  58 {
  59         int r = 32;
  60
  61         if (!x)
  62                 return 0;
  63         if (!(x & 0xFFFF0000U)) {
  64                 x <<= 16;
  65                 r -= 16;
  66         }
  67         if (!(x & 0xFF000000U)) {
  68                 x <<= 8;
  69                 r -= 8;
  70         }
  71         if (!(x & 0xF0000000U)) {
  72                 x <<= 4;
  73                 r -= 4;
  74         }
  75         if (!(x & 0xC0000000U)) {
  76                 x <<= 2;
  77                 r -= 2;
  78         }
  79         if (!(x & 0x80000000U)) {
  80                 x <<= 1;
  81                 r -= 1;
  82         }
  83         return r;
  84 }
  85
  86 #endif
  87
  88 #endif /* UST_PROCESSOR_H */