include/asm-xtensa/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 - 2005 Tensilica Inc.
  11  */
  12
  13 #ifndef _XTENSA_BITOPS_H
  14 #define _XTENSA_BITOPS_H
  15
  16 #ifdef __KERNEL__
  17
  18 #include <asm/processor.h>
  19 #include <asm/byteorder.h>
  20 #include <asm/system.h>
  21
  22 #ifdef CONFIG_SMP
  23 # error SMP not supported on this architecture
  24 #endif
  25
  26 #define smp_mb__before_clear_bit()      barrier()
  27 #define smp_mb__after_clear_bit()       barrier()
  28
  29 #include <asm-generic/bitops/atomic.h>
  30 #include <asm-generic/bitops/non-atomic.h>
  31
  32 #if XCHAL_HAVE_NSA
  33
  34 static __inline__ int __cntlz (unsigned long x)
  35 {
  36         int lz;
  37         asm ("nsau %0, %1" : "=r" (lz) : "r" (x));
  38         return 31 - lz;
  39 }
  40
  41 #else
  42
  43 static __inline__ int __cntlz (unsigned long x)
  44 {
  45         unsigned long sum, x1, x2, x4, x8, x16;
  46         x1  = x & 0xAAAAAAAA;
  47         x2  = x & 0xCCCCCCCC;
  48         x4  = x & 0xF0F0F0F0;
  49         x8  = x & 0xFF00FF00;
  50         x16 = x & 0xFFFF0000;
  51         sum = x2 ? 2 : 0;
  52         sum += (x16 != 0) * 16;
  53         sum += (x8 != 0) * 8;
  54         sum += (x4 != 0) * 4;
  55         sum += (x1 != 0);
  56
  57         return sum;
  58 }
  59
  60 #endif
  61
  62 /*
  63  * ffz: Find first zero in word. Undefined if no zero exists.
  64  * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
  65  */
  66
  67 static __inline__ int ffz(unsigned long x)
  68 {
  69         if ((x = ~x) == 0)
  70                 return 32;
  71         return __cntlz(x & -x);
  72 }
  73
  74 /*
  75  * __ffs: Find first bit set in word. Return 0 for bit 0
  76  */
  77
  78 static __inline__ int __ffs(unsigned long x)
  79 {
  80         return __cntlz(x & -x);
  81 }
  82
  83 /*
  84  * ffs: Find first bit set in word. This is defined the same way as
  85  * the libc and compiler builtin ffs routines, therefore
  86  * differs in spirit from the above ffz (man ffs).
  87  */
  88
  89 static __inline__ int ffs(unsigned long x)
  90 {
  91         return __cntlz(x & -x) + 1;
  92 }
  93
  94 /*
  95  * fls: Find last (most-significant) bit set in word.
  96  * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
  97  */
  98
  99 static __inline__ int fls (unsigned int x)
 100 {
 101         return __cntlz(x);
 102 }
 103 #include <asm-generic/bitops/fls64.h>
 104 #include <asm-generic/bitops/find.h>
 105 #include <asm-generic/bitops/ext2-non-atomic.h>
 106
 107 #ifdef __XTENSA_EL__
 108 # define ext2_set_bit_atomic(lock,nr,addr) test_and_set_bit((nr),(addr))
 109 # define ext2_clear_bit_atomic(lock,nr,addr) test_and_clear_bit((nr),(addr))
 110 #elif defined(__XTENSA_EB__)
 111 # define ext2_set_bit_atomic(lock,nr,addr) test_and_set_bit((nr) ^ 0x18, (addr))
 112 # define ext2_clear_bit_atomic(lock,nr,addr) test_and_clear_bit((nr)^0x18,(addr))
 113 #else
 114 # error processor byte order undefined!
 115 #endif
 116
 117 #include <asm-generic/bitops/hweight.h>
 118 #include <asm-generic/bitops/sched.h>
 119 #include <asm-generic/bitops/minix.h>
 120
 121 #endif  /* __KERNEL__ */
 122
 123 #endif  /* _XTENSA_BITOPS_H */