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
  25 #ifdef CONFIG_SMP
  26 # error SMP not supported on this architecture
  27 #endif
  28
  29 #define smp_mb__before_clear_bit()      barrier()
  30 #define smp_mb__after_clear_bit()       barrier()
  31
  32 #include <asm-generic/bitops/atomic.h>
  33 #include <asm-generic/bitops/non-atomic.h>
  34
  35 #if XCHAL_HAVE_NSA
  36
  37 static inline unsigned long __cntlz (unsigned long x)
  38 {
  39         int lz;
  40         asm ("nsau %0, %1" : "=r" (lz) : "r" (x));
  41         return lz;
  42 }
  43
  44 /*
  45  * ffz: Find first zero in word. Undefined if no zero exists.
  46  * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
  47  */
  48
  49 static inline int ffz(unsigned long x)
  50 {
  51         return 31 - __cntlz(~x & -~x);
  52 }
  53
  54 /*
  55  * __ffs: Find first bit set in word. Return 0 for bit 0
  56  */
  57
  58 static inline int __ffs(unsigned long x)
  59 {
  60         return 31 - __cntlz(x & -x);
  61 }
  62
  63 /*
  64  * ffs: Find first bit set in word. This is defined the same way as
  65  * the libc and compiler builtin ffs routines, therefore
  66  * differs in spirit from the above ffz (man ffs).
  67  */
  68
  69 static inline int ffs(unsigned long x)
  70 {
  71         return 32 - __cntlz(x & -x);
  72 }
  73
  74 /*
  75  * fls: Find last (most-significant) bit set in word.
  76  * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
  77  */
  78
  79 static inline int fls (unsigned int x)
  80 {
  81         return 32 - __cntlz(x);
  82 }
  83
  84 /**
  85  * __fls - find last (most-significant) set bit in a long word
  86  * @word: the word to search
  87  *
  88  * Undefined if no set bit exists, so code should check against 0 first.
  89  */
  90 static inline unsigned long __fls(unsigned long word)
  91 {
  92         return 31 - __cntlz(word);
  93 }
  94 #else
  95
  96 /* Use the generic implementation if we don't have the nsa/nsau instructions. */
  97
  98 # include <asm-generic/bitops/ffs.h>
  99 # include <asm-generic/bitops/__ffs.h>
 100 # include <asm-generic/bitops/ffz.h>
 101 # include <asm-generic/bitops/fls.h>
 102 # include <asm-generic/bitops/__fls.h>
 103
 104 #endif
 105
 106 #include <asm-generic/bitops/fls64.h>
 107 #include <asm-generic/bitops/find.h>
 108 #include <asm-generic/bitops/le.h>
 109
 110 #include <asm-generic/bitops/ext2-atomic-setbit.h>
 111
 112 #include <asm-generic/bitops/hweight.h>
 113 #include <asm-generic/bitops/lock.h>
 114 #include <asm-generic/bitops/sched.h>
 115
 116 #endif  /* __KERNEL__ */
 117
 118 #endif  /* _XTENSA_BITOPS_H */