release/src-rt-6.x.4708/linux/linux-2.6.36/arch/xtensa/include/asm/bitops.h

   1 /*
   2  * include/asm-xtensa/bitops.h
   3  *
   4  * Atomic operations that C can't guarantee us.Useful for resource counting etc.
   5  *
   6  * This file is subject to the terms and conditions of the GNU General Public
   7  * License.  See the file "COPYING" in the main directory of this archive
   8  * for more details.
   9  *
  10  * Copyright (C) 2001 - 2007 Tensilica Inc.
  11  */
  12
  13 #ifndef _XTENSA_BITOPS_H
  14 #define _XTENSA_BITOPS_H
  15
  16 #ifdef __KERNEL__
  17
  18 #ifndef _LINUX_BITOPS_H
  19 #error only <linux/bitops.h> can be included directly
  20 #endif
  21
  22 #include <asm/processor.h>
  23 #include <asm/byteorder.h>
  24 #include <asm/system.h>
  25
  26 #ifdef CONFIG_SMP
  27 # error SMP not supported on this architecture
  28 #endif
  29
  30 #define smp_mb__before_clear_bit()      barrier()
  31 #define smp_mb__after_clear_bit()       barrier()
  32
  33 #include <asm-generic/bitops/atomic.h>
  34 #include <asm-generic/bitops/non-atomic.h>
  35
  36 #if XCHAL_HAVE_NSA
  37
  38 static inline unsigned long __cntlz (unsigned long x)
  39 {
  40         int lz;
  41         asm ("nsau %0, %1" : "=r" (lz) : "r" (x));
  42         return lz;
  43 }
  44
  45 /*
  46  * ffz: Find first zero in word. Undefined if no zero exists.
  47  * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
  48  */
  49
  50 static inline int ffz(unsigned long x)
  51 {
  52         return 31 - __cntlz(~x & -~x);
  53 }
  54
  55 /*
  56  * __ffs: Find first bit set in word. Return 0 for bit 0
  57  */
  58
  59 static inline int __ffs(unsigned long x)
  60 {
  61         return 31 - __cntlz(x & -x);
  62 }
  63
  64 /*
  65  * ffs: Find first bit set in word. This is defined the same way as
  66  * the libc and compiler builtin ffs routines, therefore
  67  * differs in spirit from the above ffz (man ffs).
  68  */
  69
  70 static inline int ffs(unsigned long x)
  71 {
  72         return 32 - __cntlz(x & -x);
  73 }
  74
  75 /*
  76  * fls: Find last (most-significant) bit set in word.
  77  * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
  78  */
  79
  80 static inline int fls (unsigned int x)
  81 {
  82         return 32 - __cntlz(x);
  83 }
  84
  85 /**
  86  * __fls - find last (most-significant) set bit in a long word
  87  * @word: the word to search
  88  *
  89  * Undefined if no set bit exists, so code should check against 0 first.
  90  */
  91 static inline unsigned long __fls(unsigned long word)
  92 {
  93         return 31 - __cntlz(word);
  94 }
  95 #else
  96
  97 /* Use the generic implementation if we don't have the nsa/nsau instructions. */
  98
  99 # include <asm-generic/bitops/ffs.h>
 100 # include <asm-generic/bitops/__ffs.h>
 101 # include <asm-generic/bitops/ffz.h>
 102 # include <asm-generic/bitops/fls.h>
 103 # include <asm-generic/bitops/__fls.h>
 104
 105 #endif
 106
 107 #include <asm-generic/bitops/fls64.h>
 108 #include <asm-generic/bitops/find.h>
 109 #include <asm-generic/bitops/ext2-non-atomic.h>
 110
 111 #ifdef __XTENSA_EL__
 112 # define ext2_set_bit_atomic(lock,nr,addr)                              \
 113         test_and_set_bit((nr), (unsigned long*)(addr))
 114 # define ext2_clear_bit_atomic(lock,nr,addr)                            \
 115         test_and_clear_bit((nr), (unsigned long*)(addr))
 116 #elif defined(__XTENSA_EB__)
 117 # define ext2_set_bit_atomic(lock,nr,addr)                              \
 118         test_and_set_bit((nr) ^ 0x18, (unsigned long*)(addr))
 119 # define ext2_clear_bit_atomic(lock,nr,addr)                            \
 120         test_and_clear_bit((nr) ^ 0x18, (unsigned long*)(addr))
 121 #else
 122 # error processor byte order undefined!
 123 #endif
 124
 125 #include <asm-generic/bitops/hweight.h>
 126 #include <asm-generic/bitops/lock.h>
 127 #include <asm-generic/bitops/sched.h>
 128 #include <asm-generic/bitops/minix.h>
 129
 130 #endif  /* __KERNEL__ */
 131
 132 #endif  /* _XTENSA_BITOPS_H */