include/asm-arm26/bitops.h

   1 /*
   2  * Copyright 1995, Russell King.
   3  *
   4  * Based on the arm32 version by RMK (and others). Their copyrights apply to
   5  * Those parts.
   6  * Modified for arm26 by Ian Molton on 25/11/04
   7  *
   8  * bit 0 is the LSB of an "unsigned long" quantity.
   9  *
  10  * Please note that the code in this file should never be included
  11  * from user space.  Many of these are not implemented in assembler
  12  * since they would be too costly.  Also, they require privileged
  13  * instructions (which are not available from user mode) to ensure
  14  * that they are atomic.
  15  */
  16
  17 #ifndef __ASM_ARM_BITOPS_H
  18 #define __ASM_ARM_BITOPS_H
  19
  20 #ifdef __KERNEL__
  21
  22 #include <linux/compiler.h>
  23 #include <asm/system.h>
  24
  25 #define smp_mb__before_clear_bit()      do { } while (0)
  26 #define smp_mb__after_clear_bit()       do { } while (0)
  27
  28 /*
  29  * These functions are the basis of our bit ops.
  30  *
  31  * First, the atomic bitops. These use native endian.
  32  */
  33 static inline void ____atomic_set_bit(unsigned int bit, volatile unsigned long *p)
  34 {
  35         unsigned long flags;
  36         unsigned long mask = 1UL << (bit & 31);
  37
  38         p += bit >> 5;
  39
  40         local_irq_save(flags);
  41         *p |= mask;
  42         local_irq_restore(flags);
  43 }
  44
  45 static inline void ____atomic_clear_bit(unsigned int bit, volatile unsigned long *p)
  46 {
  47         unsigned long flags;
  48         unsigned long mask = 1UL << (bit & 31);
  49
  50         p += bit >> 5;
  51
  52         local_irq_save(flags);
  53         *p &= ~mask;
  54         local_irq_restore(flags);
  55 }
  56
  57 static inline void ____atomic_change_bit(unsigned int bit, volatile unsigned long *p)
  58 {
  59         unsigned long flags;
  60         unsigned long mask = 1UL << (bit & 31);
  61
  62         p += bit >> 5;
  63
  64         local_irq_save(flags);
  65         *p ^= mask;
  66         local_irq_restore(flags);
  67 }
  68
  69 static inline int
  70 ____atomic_test_and_set_bit(unsigned int bit, volatile unsigned long *p)
  71 {
  72         unsigned long flags;
  73         unsigned int res;
  74         unsigned long mask = 1UL << (bit & 31);
  75
  76         p += bit >> 5;
  77
  78         local_irq_save(flags);
  79         res = *p;
  80         *p = res | mask;
  81         local_irq_restore(flags);
  82
  83         return res & mask;
  84 }
  85
  86 static inline int
  87 ____atomic_test_and_clear_bit(unsigned int bit, volatile unsigned long *p)
  88 {
  89         unsigned long flags;
  90         unsigned int res;
  91         unsigned long mask = 1UL << (bit & 31);
  92
  93         p += bit >> 5;
  94
  95         local_irq_save(flags);
  96         res = *p;
  97         *p = res & ~mask;
  98         local_irq_restore(flags);
  99
 100         return res & mask;
 101 }
 102
 103 static inline int
 104 ____atomic_test_and_change_bit(unsigned int bit, volatile unsigned long *p)
 105 {
 106         unsigned long flags;
 107         unsigned int res;
 108         unsigned long mask = 1UL << (bit & 31);
 109
 110         p += bit >> 5;
 111
 112         local_irq_save(flags);
 113         res = *p;
 114         *p = res ^ mask;
 115         local_irq_restore(flags);
 116
 117         return res & mask;
 118 }
 119
 120 /*
 121  * Now the non-atomic variants.  We let the compiler handle all
 122  * optimisations for these.  These are all _native_ endian.
 123  */
 124 static inline void __set_bit(int nr, volatile unsigned long *p)
 125 {
 126         p[nr >> 5] |= (1UL << (nr & 31));
 127 }
 128
 129 static inline void __clear_bit(int nr, volatile unsigned long *p)
 130 {
 131         p[nr >> 5] &= ~(1UL << (nr & 31));
 132 }
 133
 134 static inline void __change_bit(int nr, volatile unsigned long *p)
 135 {
 136         p[nr >> 5] ^= (1UL << (nr & 31));
 137 }
 138
 139 static inline int __test_and_set_bit(int nr, volatile unsigned long *p)
 140 {
 141         unsigned long oldval, mask = 1UL << (nr & 31);
 142
 143         p += nr >> 5;
 144
 145         oldval = *p;
 146         *p = oldval | mask;
 147         return oldval & mask;
 148 }
 149
 150 static inline int __test_and_clear_bit(int nr, volatile unsigned long *p)
 151 {
 152         unsigned long oldval, mask = 1UL << (nr & 31);
 153
 154         p += nr >> 5;
 155
 156         oldval = *p;
 157         *p = oldval & ~mask;
 158         return oldval & mask;
 159 }
 160
 161 static inline int __test_and_change_bit(int nr, volatile unsigned long *p)
 162 {
 163         unsigned long oldval, mask = 1UL << (nr & 31);
 164
 165         p += nr >> 5;
 166
 167         oldval = *p;
 168         *p = oldval ^ mask;
 169         return oldval & mask;
 170 }
 171
 172 /*
 173  * This routine doesn't need to be atomic.
 174  */
 175 static inline int __test_bit(int nr, const volatile unsigned long * p)
 176 {
 177         return (p[nr >> 5] >> (nr & 31)) & 1UL;
 178 }
 179
 180 /*
 181  * Little endian assembly bitops.  nr = 0 -> byte 0 bit 0.
 182  */
 183 extern void _set_bit_le(int nr, volatile unsigned long * p);
 184 extern void _clear_bit_le(int nr, volatile unsigned long * p);
 185 extern void _change_bit_le(int nr, volatile unsigned long * p);
 186 extern int _test_and_set_bit_le(int nr, volatile unsigned long * p);
 187 extern int _test_and_clear_bit_le(int nr, volatile unsigned long * p);
 188 extern int _test_and_change_bit_le(int nr, volatile unsigned long * p);
 189 extern int _find_first_zero_bit_le(void * p, unsigned size);
 190 extern int _find_next_zero_bit_le(void * p, int size, int offset);
 191 extern int _find_first_bit_le(const unsigned long *p, unsigned size);
 192 extern int _find_next_bit_le(const unsigned long *p, int size, int offset);
 193
 194 /*
 195  * The __* form of bitops are non-atomic and may be reordered.
 196  */
 197 #define ATOMIC_BITOP_LE(name,nr,p)              \
 198         (__builtin_constant_p(nr) ?             \
 199          ____atomic_##name(nr, p) :             \
 200          _##name##_le(nr,p))
 201
 202 #define NONATOMIC_BITOP(name,nr,p)              \
 203         (____nonatomic_##name(nr, p))
 204
 205 /*
 206  * These are the little endian, atomic definitions.
 207  */
 208 #define set_bit(nr,p)                   ATOMIC_BITOP_LE(set_bit,nr,p)
 209 #define clear_bit(nr,p)                 ATOMIC_BITOP_LE(clear_bit,nr,p)
 210 #define change_bit(nr,p)                ATOMIC_BITOP_LE(change_bit,nr,p)
 211 #define test_and_set_bit(nr,p)          ATOMIC_BITOP_LE(test_and_set_bit,nr,p)
 212 #define test_and_clear_bit(nr,p)        ATOMIC_BITOP_LE(test_and_clear_bit,nr,p)
 213 #define test_and_change_bit(nr,p)       ATOMIC_BITOP_LE(test_and_change_bit,nr,p)
 214 #define test_bit(nr,p)                  __test_bit(nr,p)
 215 #define find_first_zero_bit(p,sz)       _find_first_zero_bit_le(p,sz)
 216 #define find_next_zero_bit(p,sz,off)    _find_next_zero_bit_le(p,sz,off)
 217 #define find_first_bit(p,sz)            _find_first_bit_le(p,sz)
 218 #define find_next_bit(p,sz,off)         _find_next_bit_le(p,sz,off)
 219
 220 #define WORD_BITOFF_TO_LE(x)            ((x))
 221
 222 /*
 223  * ffz = Find First Zero in word. Undefined if no zero exists,
 224  * so code should check against ~0UL first..
 225  */
 226 static inline unsigned long ffz(unsigned long word)
 227 {
 228         int k;
 229
 230         word = ~word;
 231         k = 31;
 232         if (word & 0x0000ffff) { k -= 16; word <<= 16; }
 233         if (word & 0x00ff0000) { k -= 8;  word <<= 8;  }
 234         if (word & 0x0f000000) { k -= 4;  word <<= 4;  }
 235         if (word & 0x30000000) { k -= 2;  word <<= 2;  }
 236         if (word & 0x40000000) { k -= 1; }
 237         return k;
 238 }
 239
 240 /*
 241  * ffz = Find First Zero in word. Undefined if no zero exists,
 242  * so code should check against ~0UL first..
 243  */
 244 static inline unsigned long __ffs(unsigned long word)
 245 {
 246         int k;
 247
 248         k = 31;
 249         if (word & 0x0000ffff) { k -= 16; word <<= 16; }
 250         if (word & 0x00ff0000) { k -= 8;  word <<= 8;  }
 251         if (word & 0x0f000000) { k -= 4;  word <<= 4;  }
 252         if (word & 0x30000000) { k -= 2;  word <<= 2;  }
 253         if (word & 0x40000000) { k -= 1; }
 254         return k;
 255 }
 256
 257 /*
 258  * fls: find last bit set.
 259  */
 260
 261 #define fls(x) generic_fls(x)
 262
 263 /*
 264  * ffs: find first bit set. This is defined the same way as
 265  * the libc and compiler builtin ffs routines, therefore
 266  * differs in spirit from the above ffz (man ffs).
 267  */
 268
 269 #define ffs(x) generic_ffs(x)
 270
 271 /*
 272  * Find first bit set in a 168-bit bitmap, where the first
 273  * 128 bits are unlikely to be set.
 274  */
 275 static inline int sched_find_first_bit(unsigned long *b)
 276 {
 277         unsigned long v;
 278         unsigned int off;
 279
 280         for (off = 0; v = b[off], off < 4; off++) {
 281                 if (unlikely(v))
 282                         break;
 283         }
 284         return __ffs(v) + off * 32;
 285 }
 286
 287 /*
 288  * hweightN: returns the hamming weight (i.e. the number
 289  * of bits set) of a N-bit word
 290  */
 291
 292 #define hweight32(x) generic_hweight32(x)
 293 #define hweight16(x) generic_hweight16(x)
 294 #define hweight8(x) generic_hweight8(x)
 295
 296 /*
 297  * Ext2 is defined to use little-endian byte ordering.
 298  * These do not need to be atomic.
 299  */
 300 #define ext2_set_bit(nr,p)                      \
 301                 __test_and_set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
 302 #define ext2_set_bit_atomic(lock,nr,p)          \
 303                 test_and_set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
 304 #define ext2_clear_bit(nr,p)                    \
 305                 __test_and_clear_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
 306 #define ext2_clear_bit_atomic(lock,nr,p)        \
 307                 test_and_clear_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
 308 #define ext2_test_bit(nr,p)                     \
 309                 __test_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
 310 #define ext2_find_first_zero_bit(p,sz)          \
 311                 _find_first_zero_bit_le(p,sz)
 312 #define ext2_find_next_zero_bit(p,sz,off)       \
 313                 _find_next_zero_bit_le(p,sz,off)
 314
 315 /*
 316  * Minix is defined to use little-endian byte ordering.
 317  * These do not need to be atomic.
 318  */
 319 #define minix_set_bit(nr,p)                     \
 320                 __set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
 321 #define minix_test_bit(nr,p)                    \
 322                 __test_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
 323 #define minix_test_and_set_bit(nr,p)            \
 324                 __test_and_set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
 325 #define minix_test_and_clear_bit(nr,p)          \
 326                 __test_and_clear_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
 327 #define minix_find_first_zero_bit(p,sz)         \
 328                 _find_first_zero_bit_le(p,sz)
 329
 330 #endif /* __KERNEL__ */
 331
 332 #endif /* _ARM_BITOPS_H */