linux-old/include/asm-ia64/bitops.h
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   1#ifndef _ASM_IA64_BITOPS_H
   2#define _ASM_IA64_BITOPS_H
   3
   4/*
   5 * Copyright (C) 1998-2003 Hewlett-Packard Co
   6 *      David Mosberger-Tang <davidm@hpl.hp.com>
   7 */
   8
   9#include <linux/types.h>
  10
  11#include <asm/intrinsics.h>
  12
  13/**
  14 * set_bit - Atomically set a bit in memory
  15 * @nr: the bit to set
  16 * @addr: the address to start counting from
  17 *
  18 * This function is atomic and may not be reordered.  See __set_bit()
  19 * if you do not require the atomic guarantees.
  20 * Note that @nr may be almost arbitrarily large; this function is not
  21 * restricted to acting on a single-word quantity.
  22 *
  23 * The address must be (at least) "long" aligned.
  24 * Note that there are driver (e.g., eepro100) which use these operations to operate on
  25 * hw-defined data-structures, so we can't easily change these operations to force a
  26 * bigger alignment.
  27 *
  28 * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
  29 */
  30static __inline__ void
  31set_bit (int nr, volatile void *addr)
  32{
  33        __u32 bit, old, new;
  34        volatile __u32 *m;
  35        CMPXCHG_BUGCHECK_DECL
  36
  37        m = (volatile __u32 *) addr + (nr >> 5);
  38        bit = 1 << (nr & 31);
  39        do {
  40                CMPXCHG_BUGCHECK(m);
  41                old = *m;
  42                new = old | bit;
  43        } while (cmpxchg_acq(m, old, new) != old);
  44}
  45
  46/**
  47 * __set_bit - Set a bit in memory
  48 * @nr: the bit to set
  49 * @addr: the address to start counting from
  50 *
  51 * Unlike set_bit(), this function is non-atomic and may be reordered.
  52 * If it's called on the same region of memory simultaneously, the effect
  53 * may be that only one operation succeeds.
  54 */
  55static __inline__ void
  56__set_bit (int nr, volatile void *addr)
  57{
  58        *((__u32 *) addr + (nr >> 5)) |= (1 << (nr & 31));
  59}
  60
  61/*
  62 * clear_bit() has "acquire" semantics.
  63 */
  64#define smp_mb__before_clear_bit()      smp_mb()
  65#define smp_mb__after_clear_bit()       do { /* skip */; } while (0)
  66
  67/**
  68 * clear_bit - Clears a bit in memory
  69 * @nr: Bit to clear
  70 * @addr: Address to start counting from
  71 *
  72 * clear_bit() is atomic and may not be reordered.  However, it does
  73 * not contain a memory barrier, so if it is used for locking purposes,
  74 * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit()
  75 * in order to ensure changes are visible on other processors.
  76 */
  77static __inline__ void
  78clear_bit (int nr, volatile void *addr)
  79{
  80        __u32 mask, old, new;
  81        volatile __u32 *m;
  82        CMPXCHG_BUGCHECK_DECL
  83
  84        m = (volatile __u32 *) addr + (nr >> 5);
  85        mask = ~(1 << (nr & 31));
  86        do {
  87                CMPXCHG_BUGCHECK(m);
  88                old = *m;
  89                new = old & mask;
  90        } while (cmpxchg_acq(m, old, new) != old);
  91}
  92
  93/**
  94 * change_bit - Toggle a bit in memory
  95 * @nr: Bit to clear
  96 * @addr: Address to start counting from
  97 *
  98 * change_bit() is atomic and may not be reordered.
  99 * Note that @nr may be almost arbitrarily large; this function is not
 100 * restricted to acting on a single-word quantity.
 101 */
 102static __inline__ void
 103change_bit (int nr, volatile void *addr)
 104{
 105        __u32 bit, old, new;
 106        volatile __u32 *m;
 107        CMPXCHG_BUGCHECK_DECL
 108
 109        m = (volatile __u32 *) addr + (nr >> 5);
 110        bit = (1 << (nr & 31));
 111        do {
 112                CMPXCHG_BUGCHECK(m);
 113                old = *m;
 114                new = old ^ bit;
 115        } while (cmpxchg_acq(m, old, new) != old);
 116}
 117
 118/**
 119 * __change_bit - Toggle a bit in memory
 120 * @nr: the bit to set
 121 * @addr: the address to start counting from
 122 *
 123 * Unlike change_bit(), this function is non-atomic and may be reordered.
 124 * If it's called on the same region of memory simultaneously, the effect
 125 * may be that only one operation succeeds.
 126 */
 127static __inline__ void
 128__change_bit (int nr, volatile void *addr)
 129{
 130        *((__u32 *) addr + (nr >> 5)) ^= (1 << (nr & 31));
 131}
 132
 133/**
 134 * test_and_set_bit - Set a bit and return its old value
 135 * @nr: Bit to set
 136 * @addr: Address to count from
 137 *
 138 * This operation is atomic and cannot be reordered.  
 139 * It also implies a memory barrier.
 140 */
 141static __inline__ int
 142test_and_set_bit (int nr, volatile void *addr)
 143{
 144        __u32 bit, old, new;
 145        volatile __u32 *m;
 146        CMPXCHG_BUGCHECK_DECL
 147
 148        m = (volatile __u32 *) addr + (nr >> 5);
 149        bit = 1 << (nr & 31);
 150        do {
 151                CMPXCHG_BUGCHECK(m);
 152                old = *m;
 153                new = old | bit;
 154        } while (cmpxchg_acq(m, old, new) != old);
 155        return (old & bit) != 0;
 156}
 157
 158/**
 159 * __test_and_set_bit - Set a bit and return its old value
 160 * @nr: Bit to set
 161 * @addr: Address to count from
 162 *
 163 * This operation is non-atomic and can be reordered.  
 164 * If two examples of this operation race, one can appear to succeed
 165 * but actually fail.  You must protect multiple accesses with a lock.
 166 */
 167static __inline__ int
 168__test_and_set_bit (int nr, volatile void *addr)
 169{
 170        __u32 *p = (__u32 *) addr + (nr >> 5);
 171        __u32 m = 1 << (nr & 31);
 172        int oldbitset = (*p & m) != 0;
 173
 174        *p |= m;
 175        return oldbitset;
 176}
 177
 178/**
 179 * test_and_clear_bit - Clear a bit and return its old value
 180 * @nr: Bit to set
 181 * @addr: Address to count from
 182 *
 183 * This operation is atomic and cannot be reordered.  
 184 * It also implies a memory barrier.
 185 */
 186static __inline__ int
 187test_and_clear_bit (int nr, volatile void *addr)
 188{
 189        __u32 mask, old, new;
 190        volatile __u32 *m;
 191        CMPXCHG_BUGCHECK_DECL
 192
 193        m = (volatile __u32 *) addr + (nr >> 5);
 194        mask = ~(1 << (nr & 31));
 195        do {
 196                CMPXCHG_BUGCHECK(m);
 197                old = *m;
 198                new = old & mask;
 199        } while (cmpxchg_acq(m, old, new) != old);
 200        return (old & ~mask) != 0;
 201}
 202
 203/**
 204 * __test_and_clear_bit - Clear a bit and return its old value
 205 * @nr: Bit to set
 206 * @addr: Address to count from
 207 *
 208 * This operation is non-atomic and can be reordered.  
 209 * If two examples of this operation race, one can appear to succeed
 210 * but actually fail.  You must protect multiple accesses with a lock.
 211 */
 212static __inline__ int
 213__test_and_clear_bit(int nr, volatile void * addr)
 214{
 215        __u32 *p = (__u32 *) addr + (nr >> 5);
 216        __u32 m = 1 << (nr & 31);
 217        int oldbitset = *p & m;
 218
 219        *p &= ~m;
 220        return oldbitset;
 221}
 222
 223/**
 224 * test_and_change_bit - Change a bit and return its new value
 225 * @nr: Bit to set
 226 * @addr: Address to count from
 227 *
 228 * This operation is atomic and cannot be reordered.  
 229 * It also implies a memory barrier.
 230 */
 231static __inline__ int
 232test_and_change_bit (int nr, volatile void *addr)
 233{
 234        __u32 bit, old, new;
 235        volatile __u32 *m;
 236        CMPXCHG_BUGCHECK_DECL
 237
 238        m = (volatile __u32 *) addr + (nr >> 5);
 239        bit = (1 << (nr & 31));
 240        do {
 241                CMPXCHG_BUGCHECK(m);
 242                old = *m;
 243                new = old ^ bit;
 244        } while (cmpxchg_acq(m, old, new) != old);
 245        return (old & bit) != 0;
 246}
 247
 248/*
 249 * WARNING: non atomic version.
 250 */
 251static __inline__ int
 252__test_and_change_bit (int nr, void *addr)
 253{
 254        __u32 old, bit = (1 << (nr & 31));
 255        __u32 *m = (__u32 *) addr + (nr >> 5);
 256
 257        old = *m;
 258        *m = old ^ bit;
 259        return (old & bit) != 0;
 260}
 261
 262static __inline__ int
 263test_bit (int nr, const volatile void *addr)
 264{
 265        return 1 & (((const volatile __u32 *) addr)[nr >> 5] >> (nr & 31));
 266}
 267
 268/**
 269 * ffz - find the first zero bit in a memory region
 270 * @x: The address to start the search at
 271 *
 272 * Returns the bit-number (0..63) of the first (least significant) zero bit, not
 273 * the number of the byte containing a bit.  Undefined if no zero exists, so
 274 * code should check against ~0UL first...
 275 */
 276static inline unsigned long
 277ffz (unsigned long x)
 278{
 279        unsigned long result;
 280
 281        __asm__ ("popcnt %0=%1" : "=r" (result) : "r" (x & (~x - 1)));
 282        return result;
 283}
 284
 285/**
 286 * __ffs - find first bit in word.
 287 * @x: The word to search
 288 *
 289 * Undefined if no bit exists, so code should check against 0 first.
 290 */
 291static __inline__ unsigned long
 292__ffs (unsigned long x)
 293{
 294        unsigned long result;
 295
 296        __asm__ ("popcnt %0=%1" : "=r" (result) : "r" ((x - 1) & ~x));
 297        return result;
 298}
 299
 300#ifdef __KERNEL__
 301
 302/*
 303 * find_last_zero_bit - find the last zero bit in a 64 bit quantity
 304 * @x: The value to search
 305 */
 306static inline unsigned long
 307ia64_fls (unsigned long x)
 308{
 309        long double d = x;
 310        long exp;
 311
 312        __asm__ ("getf.exp %0=%1" : "=r"(exp) : "f"(d));
 313        return exp - 0xffff;
 314}
 315
 316/*
 317 * ffs: find first bit set. This is defined the same way as the libc and compiler builtin
 318 * ffs routines, therefore differs in spirit from the above ffz (man ffs): it operates on
 319 * "int" values only and the result value is the bit number + 1.  ffs(0) is defined to
 320 * return zero.
 321 */
 322#define ffs(x)  __builtin_ffs(x)
 323
 324/*
 325 * hweightN: returns the hamming weight (i.e. the number
 326 * of bits set) of a N-bit word
 327 */
 328static __inline__ unsigned long
 329hweight64 (unsigned long x)
 330{
 331        unsigned long result;
 332        __asm__ ("popcnt %0=%1" : "=r" (result) : "r" (x));
 333        return result;
 334}
 335
 336#define hweight32(x) hweight64 ((x) & 0xfffffffful)
 337#define hweight16(x) hweight64 ((x) & 0xfffful)
 338#define hweight8(x)  hweight64 ((x) & 0xfful)
 339
 340#endif /* __KERNEL__ */
 341
 342/*
 343 * Find next zero bit in a bitmap reasonably efficiently..
 344 */
 345static inline unsigned long
 346find_next_zero_bit (void *addr, unsigned long size, unsigned long offset)
 347{
 348        unsigned long *p = ((unsigned long *) addr) + (offset >> 6);
 349        unsigned long result = offset & ~63UL;
 350        unsigned long tmp;
 351
 352        if (offset >= size)
 353                return size;
 354        size -= result;
 355        offset &= 63UL;
 356        if (offset) {
 357                tmp = *(p++);
 358                tmp |= ~0UL >> (64-offset);
 359                if (size < 64)
 360                        goto found_first;
 361                if (~tmp)
 362                        goto found_middle;
 363                size -= 64;
 364                result += 64;
 365        }
 366        while (size & ~63UL) {
 367                if (~(tmp = *(p++)))
 368                        goto found_middle;
 369                result += 64;
 370                size -= 64;
 371        }
 372        if (!size)
 373                return result;
 374        tmp = *p;
 375found_first:
 376        tmp |= ~0UL << size;
 377        if (tmp == ~0UL)                /* any bits zero? */
 378                return result + size;   /* nope */
 379found_middle:
 380        return result + ffz(tmp);
 381}
 382
 383/*
 384 * The optimizer actually does good code for this case..
 385 */
 386#define find_first_zero_bit(addr, size) find_next_zero_bit((addr), (size), 0)
 387
 388#ifdef __KERNEL__
 389
 390#define ext2_set_bit                 test_and_set_bit
 391#define ext2_clear_bit               test_and_clear_bit
 392#define ext2_test_bit                test_bit
 393#define ext2_find_first_zero_bit     find_first_zero_bit
 394#define ext2_find_next_zero_bit      find_next_zero_bit
 395
 396/* Bitmap functions for the minix filesystem.  */
 397#define minix_test_and_set_bit(nr,addr)         test_and_set_bit(nr,addr)
 398#define minix_set_bit(nr,addr)                  set_bit(nr,addr)
 399#define minix_test_and_clear_bit(nr,addr)       test_and_clear_bit(nr,addr)
 400#define minix_test_bit(nr,addr)                 test_bit(nr,addr)
 401#define minix_find_first_zero_bit(addr,size)    find_first_zero_bit(addr,size)
 402
 403#endif /* __KERNEL__ */
 404
 405#endif /* _ASM_IA64_BITOPS_H */
 406
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