include/asm-cris/bitops.h

   1 /* asm/bitops.h for Linux/CRIS
   2  *
   3  * TODO: asm versions if speed is needed
   4  *
   5  * All bit operations return 0 if the bit was cleared before the
   6  * operation and != 0 if it was not.
   7  *
   8  * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
   9  */
  10
  11 #ifndef _CRIS_BITOPS_H
  12 #define _CRIS_BITOPS_H
  13
  14 /* Currently this is unsuitable for consumption outside the kernel.  */
  15 #ifdef __KERNEL__
  16
  17 #include <asm/arch/bitops.h>
  18 #include <asm/system.h>
  19 #include <asm/atomic.h>
  20 #include <linux/compiler.h>
  21
  22 /*
  23  * Some hacks to defeat gcc over-optimizations..
  24  */
  25 struct __dummy { unsigned long a[100]; };
  26 #define ADDR (*(struct __dummy *) addr)
  27 #define CONST_ADDR (*(const struct __dummy *) addr)
  28
  29 /*
  30  * set_bit - Atomically set a bit in memory
  31  * @nr: the bit to set
  32  * @addr: the address to start counting from
  33  *
  34  * This function is atomic and may not be reordered.  See __set_bit()
  35  * if you do not require the atomic guarantees.
  36  * Note that @nr may be almost arbitrarily large; this function is not
  37  * restricted to acting on a single-word quantity.
  38  */
  39
  40 #define set_bit(nr, addr)    (void)test_and_set_bit(nr, addr)
  41
  42 #define __set_bit(nr, addr)    (void)__test_and_set_bit(nr, addr)
  43
  44 /*
  45  * clear_bit - Clears a bit in memory
  46  * @nr: Bit to clear
  47  * @addr: Address to start counting from
  48  *
  49  * clear_bit() is atomic and may not be reordered.  However, it does
  50  * not contain a memory barrier, so if it is used for locking purposes,
  51  * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit()
  52  * in order to ensure changes are visible on other processors.
  53  */
  54
  55 #define clear_bit(nr, addr)  (void)test_and_clear_bit(nr, addr)
  56
  57 #define __clear_bit(nr, addr)  (void)__test_and_clear_bit(nr, addr)
  58
  59 /*
  60  * change_bit - Toggle a bit in memory
  61  * @nr: Bit to change
  62  * @addr: Address to start counting from
  63  *
  64  * change_bit() is atomic and may not be reordered.
  65  * Note that @nr may be almost arbitrarily large; this function is not
  66  * restricted to acting on a single-word quantity.
  67  */
  68
  69 #define change_bit(nr, addr) (void)test_and_change_bit(nr, addr)
  70
  71 /*
  72  * __change_bit - Toggle a bit in memory
  73  * @nr: the bit to change
  74  * @addr: the address to start counting from
  75  *
  76  * Unlike change_bit(), this function is non-atomic and may be reordered.
  77  * If it's called on the same region of memory simultaneously, the effect
  78  * may be that only one operation succeeds.
  79  */
  80
  81 #define __change_bit(nr, addr) (void)__test_and_change_bit(nr, addr)
  82
  83 /**
  84  * test_and_set_bit - Set a bit and return its old value
  85  * @nr: Bit to set
  86  * @addr: Address to count from
  87  *
  88  * This operation is atomic and cannot be reordered.
  89  * It also implies a memory barrier.
  90  */
  91
  92 static inline int test_and_set_bit(int nr, volatile unsigned long *addr)
  93 {
  94         unsigned int mask, retval;
  95         unsigned long flags;
  96         unsigned int *adr = (unsigned int *)addr;
  97
  98         adr += nr >> 5;
  99         mask = 1 << (nr & 0x1f);
 100         cris_atomic_save(addr, flags);
 101         retval = (mask & *adr) != 0;
 102         *adr |= mask;
 103         cris_atomic_restore(addr, flags);
 104         local_irq_restore(flags);
 105         return retval;
 106 }
 107
 108 static inline int __test_and_set_bit(int nr, volatile unsigned long *addr)
 109 {
 110         unsigned int mask, retval;
 111         unsigned int *adr = (unsigned int *)addr;
 112
 113         adr += nr >> 5;
 114         mask = 1 << (nr & 0x1f);
 115         retval = (mask & *adr) != 0;
 116         *adr |= mask;
 117         return retval;
 118 }
 119
 120 /*
 121  * clear_bit() doesn't provide any barrier for the compiler.
 122  */
 123 #define smp_mb__before_clear_bit()      barrier()
 124 #define smp_mb__after_clear_bit()       barrier()
 125
 126 /**
 127  * test_and_clear_bit - Clear a bit and return its old value
 128  * @nr: Bit to clear
 129  * @addr: Address to count from
 130  *
 131  * This operation is atomic and cannot be reordered.
 132  * It also implies a memory barrier.
 133  */
 134
 135 static inline int test_and_clear_bit(int nr, volatile unsigned long *addr)
 136 {
 137         unsigned int mask, retval;
 138         unsigned long flags;
 139         unsigned int *adr = (unsigned int *)addr;
 140
 141         adr += nr >> 5;
 142         mask = 1 << (nr & 0x1f);
 143         cris_atomic_save(addr, flags);
 144         retval = (mask & *adr) != 0;
 145         *adr &= ~mask;
 146         cris_atomic_restore(addr, flags);
 147         return retval;
 148 }
 149
 150 /**
 151  * __test_and_clear_bit - Clear a bit and return its old value
 152  * @nr: Bit to clear
 153  * @addr: Address to count from
 154  *
 155  * This operation is non-atomic and can be reordered.
 156  * If two examples of this operation race, one can appear to succeed
 157  * but actually fail.  You must protect multiple accesses with a lock.
 158  */
 159
 160 static inline int __test_and_clear_bit(int nr, volatile unsigned long *addr)
 161 {
 162         unsigned int mask, retval;
 163         unsigned int *adr = (unsigned int *)addr;
 164
 165         adr += nr >> 5;
 166         mask = 1 << (nr & 0x1f);
 167         retval = (mask & *adr) != 0;
 168         *adr &= ~mask;
 169         return retval;
 170 }
 171 /**
 172  * test_and_change_bit - Change a bit and return its old value
 173  * @nr: Bit to change
 174  * @addr: Address to count from
 175  *
 176  * This operation is atomic and cannot be reordered.
 177  * It also implies a memory barrier.
 178  */
 179
 180 static inline int test_and_change_bit(int nr, volatile unsigned long *addr)
 181 {
 182         unsigned int mask, retval;
 183         unsigned long flags;
 184         unsigned int *adr = (unsigned int *)addr;
 185         adr += nr >> 5;
 186         mask = 1 << (nr & 0x1f);
 187         cris_atomic_save(addr, flags);
 188         retval = (mask & *adr) != 0;
 189         *adr ^= mask;
 190         cris_atomic_restore(addr, flags);
 191         return retval;
 192 }
 193
 194 /* WARNING: non atomic and it can be reordered! */
 195
 196 static inline int __test_and_change_bit(int nr, volatile unsigned long *addr)
 197 {
 198         unsigned int mask, retval;
 199         unsigned int *adr = (unsigned int *)addr;
 200
 201         adr += nr >> 5;
 202         mask = 1 << (nr & 0x1f);
 203         retval = (mask & *adr) != 0;
 204         *adr ^= mask;
 205
 206         return retval;
 207 }
 208
 209 /**
 210  * test_bit - Determine whether a bit is set
 211  * @nr: bit number to test
 212  * @addr: Address to start counting from
 213  *
 214  * This routine doesn't need to be atomic.
 215  */
 216
 217 static inline int test_bit(int nr, const volatile unsigned long *addr)
 218 {
 219         unsigned int mask;
 220         unsigned int *adr = (unsigned int *)addr;
 221
 222         adr += nr >> 5;
 223         mask = 1 << (nr & 0x1f);
 224         return ((mask & *adr) != 0);
 225 }
 226
 227 /*
 228  * Find-bit routines..
 229  */
 230
 231 /*
 232  * Since we define it "external", it collides with the built-in
 233  * definition, which doesn't have the same semantics.  We don't want to
 234  * use -fno-builtin, so just hide the name ffs.
 235  */
 236 #define ffs kernel_ffs
 237
 238 /*
 239  * fls: find last bit set.
 240  */
 241
 242 #define fls(x) generic_fls(x)
 243 #define fls64(x)   generic_fls64(x)
 244
 245 /*
 246  * hweightN - returns the hamming weight of a N-bit word
 247  * @x: the word to weigh
 248  *
 249  * The Hamming Weight of a number is the total number of bits set in it.
 250  */
 251
 252 #define hweight32(x) generic_hweight32(x)
 253 #define hweight16(x) generic_hweight16(x)
 254 #define hweight8(x) generic_hweight8(x)
 255
 256 /**
 257  * find_next_zero_bit - find the first zero bit in a memory region
 258  * @addr: The address to base the search on
 259  * @offset: The bitnumber to start searching at
 260  * @size: The maximum size to search
 261  */
 262 static inline int find_next_zero_bit (const unsigned long * addr, int size, int offset)
 263 {
 264         unsigned long *p = ((unsigned long *) addr) + (offset >> 5);
 265         unsigned long result = offset & ~31UL;
 266         unsigned long tmp;
 267
 268         if (offset >= size)
 269                 return size;
 270         size -= result;
 271         offset &= 31UL;
 272         if (offset) {
 273                 tmp = *(p++);
 274                 tmp |= ~0UL >> (32-offset);
 275                 if (size < 32)
 276                         goto found_first;
 277                 if (~tmp)
 278                         goto found_middle;
 279                 size -= 32;
 280                 result += 32;
 281         }
 282         while (size & ~31UL) {
 283                 if (~(tmp = *(p++)))
 284                         goto found_middle;
 285                 result += 32;
 286                 size -= 32;
 287         }
 288         if (!size)
 289                 return result;
 290         tmp = *p;
 291
 292  found_first:
 293         tmp |= ~0UL >> size;
 294  found_middle:
 295         return result + ffz(tmp);
 296 }
 297
 298 /**
 299  * find_next_bit - find the first set bit in a memory region
 300  * @addr: The address to base the search on
 301  * @offset: The bitnumber to start searching at
 302  * @size: The maximum size to search
 303  */
 304 static __inline__ int find_next_bit(const unsigned long *addr, int size, int offset)
 305 {
 306         unsigned long *p = ((unsigned long *) addr) + (offset >> 5);
 307         unsigned long result = offset & ~31UL;
 308         unsigned long tmp;
 309
 310         if (offset >= size)
 311                 return size;
 312         size -= result;
 313         offset &= 31UL;
 314         if (offset) {
 315                 tmp = *(p++);
 316                 tmp &= (~0UL << offset);
 317                 if (size < 32)
 318                         goto found_first;
 319                 if (tmp)
 320                         goto found_middle;
 321                 size -= 32;
 322                 result += 32;
 323         }
 324         while (size & ~31UL) {
 325                 if ((tmp = *(p++)))
 326                         goto found_middle;
 327                 result += 32;
 328                 size -= 32;
 329         }
 330         if (!size)
 331                 return result;
 332         tmp = *p;
 333
 334 found_first:
 335         tmp &= (~0UL >> (32 - size));
 336         if (tmp == 0UL)        /* Are any bits set? */
 337                 return result + size; /* Nope. */
 338 found_middle:
 339         return result + __ffs(tmp);
 340 }
 341
 342 /**
 343  * find_first_zero_bit - find the first zero bit in a memory region
 344  * @addr: The address to start the search at
 345  * @size: The maximum size to search
 346  *
 347  * Returns the bit-number of the first zero bit, not the number of the byte
 348  * containing a bit.
 349  */
 350
 351 #define find_first_zero_bit(addr, size) \
 352         find_next_zero_bit((addr), (size), 0)
 353 #define find_first_bit(addr, size) \
 354         find_next_bit((addr), (size), 0)
 355
 356 #define ext2_set_bit                 test_and_set_bit
 357 #define ext2_set_bit_atomic(l,n,a)   test_and_set_bit(n,a)
 358 #define ext2_clear_bit               test_and_clear_bit
 359 #define ext2_clear_bit_atomic(l,n,a) test_and_clear_bit(n,a)
 360 #define ext2_test_bit                test_bit
 361 #define ext2_find_first_zero_bit     find_first_zero_bit
 362 #define ext2_find_next_zero_bit      find_next_zero_bit
 363
 364 /* Bitmap functions for the minix filesystem.  */
 365 #define minix_set_bit(nr,addr) test_and_set_bit(nr,addr)
 366 #define minix_clear_bit(nr,addr) test_and_clear_bit(nr,addr)
 367 #define minix_test_bit(nr,addr) test_bit(nr,addr)
 368 #define minix_find_first_zero_bit(addr,size) find_first_zero_bit(addr,size)
 369
 370 static inline int sched_find_first_bit(const unsigned long *b)
 371 {
 372         if (unlikely(b[0]))
 373                 return __ffs(b[0]);
 374         if (unlikely(b[1]))
 375                 return __ffs(b[1]) + 32;
 376         if (unlikely(b[2]))
 377                 return __ffs(b[2]) + 64;
 378         if (unlikely(b[3]))
 379                 return __ffs(b[3]) + 96;
 380         if (b[4])
 381                 return __ffs(b[4]) + 128;
 382         return __ffs(b[5]) + 32 + 128;
 383 }
 384
 385 #endif /* __KERNEL__ */
 386
 387 #endif /* _CRIS_BITOPS_H */