Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | #ifndef _I386_BITOPS_H |
| 2 | #define _I386_BITOPS_H |
| 3 | |
| 4 | /* |
| 5 | * Copyright 1992, Linus Torvalds. |
| 6 | */ |
| 7 | |
| 8 | #include <linux/config.h> |
| 9 | #include <linux/compiler.h> |
| 10 | |
| 11 | /* |
| 12 | * These have to be done with inline assembly: that way the bit-setting |
| 13 | * is guaranteed to be atomic. All bit operations return 0 if the bit |
| 14 | * was cleared before the operation and != 0 if it was not. |
| 15 | * |
| 16 | * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1). |
| 17 | */ |
| 18 | |
| 19 | #ifdef CONFIG_SMP |
| 20 | #define LOCK_PREFIX "lock ; " |
| 21 | #else |
| 22 | #define LOCK_PREFIX "" |
| 23 | #endif |
| 24 | |
| 25 | #define ADDR (*(volatile long *) addr) |
| 26 | |
| 27 | /** |
| 28 | * set_bit - Atomically set a bit in memory |
| 29 | * @nr: the bit to set |
| 30 | * @addr: the address to start counting from |
| 31 | * |
| 32 | * This function is atomic and may not be reordered. See __set_bit() |
| 33 | * if you do not require the atomic guarantees. |
| 34 | * |
| 35 | * Note: there are no guarantees that this function will not be reordered |
| 36 | * on non x86 architectures, so if you are writting portable code, |
| 37 | * make sure not to rely on its reordering guarantees. |
| 38 | * |
| 39 | * Note that @nr may be almost arbitrarily large; this function is not |
| 40 | * restricted to acting on a single-word quantity. |
| 41 | */ |
| 42 | static inline void set_bit(int nr, volatile unsigned long * addr) |
| 43 | { |
| 44 | __asm__ __volatile__( LOCK_PREFIX |
| 45 | "btsl %1,%0" |
Andi Kleen | 92934bc | 2006-01-11 22:42:32 +0100 | [diff] [blame] | 46 | :"+m" (ADDR) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 47 | :"Ir" (nr)); |
| 48 | } |
| 49 | |
| 50 | /** |
| 51 | * __set_bit - Set a bit in memory |
| 52 | * @nr: the bit to set |
| 53 | * @addr: the address to start counting from |
| 54 | * |
| 55 | * Unlike set_bit(), this function is non-atomic and may be reordered. |
| 56 | * If it's called on the same region of memory simultaneously, the effect |
| 57 | * may be that only one operation succeeds. |
| 58 | */ |
| 59 | static inline void __set_bit(int nr, volatile unsigned long * addr) |
| 60 | { |
| 61 | __asm__( |
| 62 | "btsl %1,%0" |
Andi Kleen | 92934bc | 2006-01-11 22:42:32 +0100 | [diff] [blame] | 63 | :"+m" (ADDR) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 64 | :"Ir" (nr)); |
| 65 | } |
| 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 | */ |
| 77 | static inline void clear_bit(int nr, volatile unsigned long * addr) |
| 78 | { |
| 79 | __asm__ __volatile__( LOCK_PREFIX |
| 80 | "btrl %1,%0" |
Andi Kleen | 92934bc | 2006-01-11 22:42:32 +0100 | [diff] [blame] | 81 | :"+m" (ADDR) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 82 | :"Ir" (nr)); |
| 83 | } |
| 84 | |
| 85 | static inline void __clear_bit(int nr, volatile unsigned long * addr) |
| 86 | { |
| 87 | __asm__ __volatile__( |
| 88 | "btrl %1,%0" |
Andi Kleen | 92934bc | 2006-01-11 22:42:32 +0100 | [diff] [blame] | 89 | :"+m" (ADDR) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 90 | :"Ir" (nr)); |
| 91 | } |
| 92 | #define smp_mb__before_clear_bit() barrier() |
| 93 | #define smp_mb__after_clear_bit() barrier() |
| 94 | |
| 95 | /** |
| 96 | * __change_bit - Toggle a bit in memory |
| 97 | * @nr: the bit to change |
| 98 | * @addr: the address to start counting from |
| 99 | * |
| 100 | * Unlike change_bit(), this function is non-atomic and may be reordered. |
| 101 | * If it's called on the same region of memory simultaneously, the effect |
| 102 | * may be that only one operation succeeds. |
| 103 | */ |
| 104 | static inline void __change_bit(int nr, volatile unsigned long * addr) |
| 105 | { |
| 106 | __asm__ __volatile__( |
| 107 | "btcl %1,%0" |
Andi Kleen | 92934bc | 2006-01-11 22:42:32 +0100 | [diff] [blame] | 108 | :"+m" (ADDR) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 109 | :"Ir" (nr)); |
| 110 | } |
| 111 | |
| 112 | /** |
| 113 | * change_bit - Toggle a bit in memory |
| 114 | * @nr: Bit to change |
| 115 | * @addr: Address to start counting from |
| 116 | * |
| 117 | * change_bit() is atomic and may not be reordered. It may be |
| 118 | * reordered on other architectures than x86. |
| 119 | * Note that @nr may be almost arbitrarily large; this function is not |
| 120 | * restricted to acting on a single-word quantity. |
| 121 | */ |
| 122 | static inline void change_bit(int nr, volatile unsigned long * addr) |
| 123 | { |
| 124 | __asm__ __volatile__( LOCK_PREFIX |
| 125 | "btcl %1,%0" |
Andi Kleen | 92934bc | 2006-01-11 22:42:32 +0100 | [diff] [blame] | 126 | :"+m" (ADDR) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 127 | :"Ir" (nr)); |
| 128 | } |
| 129 | |
| 130 | /** |
| 131 | * test_and_set_bit - Set a bit and return its old value |
| 132 | * @nr: Bit to set |
| 133 | * @addr: Address to count from |
| 134 | * |
| 135 | * This operation is atomic and cannot be reordered. |
| 136 | * It may be reordered on other architectures than x86. |
| 137 | * It also implies a memory barrier. |
| 138 | */ |
| 139 | static inline int test_and_set_bit(int nr, volatile unsigned long * addr) |
| 140 | { |
| 141 | int oldbit; |
| 142 | |
| 143 | __asm__ __volatile__( LOCK_PREFIX |
| 144 | "btsl %2,%1\n\tsbbl %0,%0" |
Andi Kleen | 92934bc | 2006-01-11 22:42:32 +0100 | [diff] [blame] | 145 | :"=r" (oldbit),"+m" (ADDR) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 146 | :"Ir" (nr) : "memory"); |
| 147 | return oldbit; |
| 148 | } |
| 149 | |
| 150 | /** |
| 151 | * __test_and_set_bit - Set a bit and return its old value |
| 152 | * @nr: Bit to set |
| 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 | static inline int __test_and_set_bit(int nr, volatile unsigned long * addr) |
| 160 | { |
| 161 | int oldbit; |
| 162 | |
| 163 | __asm__( |
| 164 | "btsl %2,%1\n\tsbbl %0,%0" |
Andi Kleen | 92934bc | 2006-01-11 22:42:32 +0100 | [diff] [blame] | 165 | :"=r" (oldbit),"+m" (ADDR) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 166 | :"Ir" (nr)); |
| 167 | return oldbit; |
| 168 | } |
| 169 | |
| 170 | /** |
| 171 | * test_and_clear_bit - Clear a bit and return its old value |
| 172 | * @nr: Bit to clear |
| 173 | * @addr: Address to count from |
| 174 | * |
| 175 | * This operation is atomic and cannot be reordered. |
| 176 | * It can be reorderdered on other architectures other than x86. |
| 177 | * It also implies a memory barrier. |
| 178 | */ |
| 179 | static inline int test_and_clear_bit(int nr, volatile unsigned long * addr) |
| 180 | { |
| 181 | int oldbit; |
| 182 | |
| 183 | __asm__ __volatile__( LOCK_PREFIX |
| 184 | "btrl %2,%1\n\tsbbl %0,%0" |
Andi Kleen | 92934bc | 2006-01-11 22:42:32 +0100 | [diff] [blame] | 185 | :"=r" (oldbit),"+m" (ADDR) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 186 | :"Ir" (nr) : "memory"); |
| 187 | return oldbit; |
| 188 | } |
| 189 | |
| 190 | /** |
| 191 | * __test_and_clear_bit - Clear a bit and return its old value |
| 192 | * @nr: Bit to clear |
| 193 | * @addr: Address to count from |
| 194 | * |
| 195 | * This operation is non-atomic and can be reordered. |
| 196 | * If two examples of this operation race, one can appear to succeed |
| 197 | * but actually fail. You must protect multiple accesses with a lock. |
| 198 | */ |
| 199 | static inline int __test_and_clear_bit(int nr, volatile unsigned long *addr) |
| 200 | { |
| 201 | int oldbit; |
| 202 | |
| 203 | __asm__( |
| 204 | "btrl %2,%1\n\tsbbl %0,%0" |
Andi Kleen | 92934bc | 2006-01-11 22:42:32 +0100 | [diff] [blame] | 205 | :"=r" (oldbit),"+m" (ADDR) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 206 | :"Ir" (nr)); |
| 207 | return oldbit; |
| 208 | } |
| 209 | |
| 210 | /* WARNING: non atomic and it can be reordered! */ |
| 211 | static inline int __test_and_change_bit(int nr, volatile unsigned long *addr) |
| 212 | { |
| 213 | int oldbit; |
| 214 | |
| 215 | __asm__ __volatile__( |
| 216 | "btcl %2,%1\n\tsbbl %0,%0" |
Andi Kleen | 92934bc | 2006-01-11 22:42:32 +0100 | [diff] [blame] | 217 | :"=r" (oldbit),"+m" (ADDR) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 218 | :"Ir" (nr) : "memory"); |
| 219 | return oldbit; |
| 220 | } |
| 221 | |
| 222 | /** |
| 223 | * test_and_change_bit - Change a bit and return its old value |
| 224 | * @nr: Bit to change |
| 225 | * @addr: Address to count from |
| 226 | * |
| 227 | * This operation is atomic and cannot be reordered. |
| 228 | * It also implies a memory barrier. |
| 229 | */ |
| 230 | static inline int test_and_change_bit(int nr, volatile unsigned long* addr) |
| 231 | { |
| 232 | int oldbit; |
| 233 | |
| 234 | __asm__ __volatile__( LOCK_PREFIX |
| 235 | "btcl %2,%1\n\tsbbl %0,%0" |
Andi Kleen | 92934bc | 2006-01-11 22:42:32 +0100 | [diff] [blame] | 236 | :"=r" (oldbit),"+m" (ADDR) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 237 | :"Ir" (nr) : "memory"); |
| 238 | return oldbit; |
| 239 | } |
| 240 | |
| 241 | #if 0 /* Fool kernel-doc since it doesn't do macros yet */ |
| 242 | /** |
| 243 | * test_bit - Determine whether a bit is set |
| 244 | * @nr: bit number to test |
| 245 | * @addr: Address to start counting from |
| 246 | */ |
| 247 | static int test_bit(int nr, const volatile void * addr); |
| 248 | #endif |
| 249 | |
Ingo Molnar | 652050a | 2006-01-14 13:21:30 -0800 | [diff] [blame] | 250 | static __always_inline int constant_test_bit(int nr, const volatile unsigned long *addr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 251 | { |
| 252 | return ((1UL << (nr & 31)) & (addr[nr >> 5])) != 0; |
| 253 | } |
| 254 | |
| 255 | static inline int variable_test_bit(int nr, const volatile unsigned long * addr) |
| 256 | { |
| 257 | int oldbit; |
| 258 | |
| 259 | __asm__ __volatile__( |
| 260 | "btl %2,%1\n\tsbbl %0,%0" |
| 261 | :"=r" (oldbit) |
| 262 | :"m" (ADDR),"Ir" (nr)); |
| 263 | return oldbit; |
| 264 | } |
| 265 | |
| 266 | #define test_bit(nr,addr) \ |
| 267 | (__builtin_constant_p(nr) ? \ |
| 268 | constant_test_bit((nr),(addr)) : \ |
| 269 | variable_test_bit((nr),(addr))) |
| 270 | |
| 271 | #undef ADDR |
| 272 | |
| 273 | /** |
| 274 | * find_first_zero_bit - find the first zero bit in a memory region |
| 275 | * @addr: The address to start the search at |
| 276 | * @size: The maximum size to search |
| 277 | * |
| 278 | * Returns the bit-number of the first zero bit, not the number of the byte |
| 279 | * containing a bit. |
| 280 | */ |
| 281 | static inline int find_first_zero_bit(const unsigned long *addr, unsigned size) |
| 282 | { |
| 283 | int d0, d1, d2; |
| 284 | int res; |
| 285 | |
| 286 | if (!size) |
| 287 | return 0; |
| 288 | /* This looks at memory. Mark it volatile to tell gcc not to move it around */ |
| 289 | __asm__ __volatile__( |
| 290 | "movl $-1,%%eax\n\t" |
| 291 | "xorl %%edx,%%edx\n\t" |
| 292 | "repe; scasl\n\t" |
| 293 | "je 1f\n\t" |
| 294 | "xorl -4(%%edi),%%eax\n\t" |
| 295 | "subl $4,%%edi\n\t" |
| 296 | "bsfl %%eax,%%edx\n" |
| 297 | "1:\tsubl %%ebx,%%edi\n\t" |
| 298 | "shll $3,%%edi\n\t" |
| 299 | "addl %%edi,%%edx" |
| 300 | :"=d" (res), "=&c" (d0), "=&D" (d1), "=&a" (d2) |
| 301 | :"1" ((size + 31) >> 5), "2" (addr), "b" (addr) : "memory"); |
| 302 | return res; |
| 303 | } |
| 304 | |
| 305 | /** |
| 306 | * find_next_zero_bit - find the first zero bit in a memory region |
| 307 | * @addr: The address to base the search on |
| 308 | * @offset: The bitnumber to start searching at |
| 309 | * @size: The maximum size to search |
| 310 | */ |
| 311 | int find_next_zero_bit(const unsigned long *addr, int size, int offset); |
| 312 | |
| 313 | /** |
Steven Rostedt | cd85c8b | 2005-07-28 08:45:06 -0400 | [diff] [blame] | 314 | * __ffs - find first bit in word. |
| 315 | * @word: The word to search |
| 316 | * |
| 317 | * Undefined if no bit exists, so code should check against 0 first. |
| 318 | */ |
| 319 | static inline unsigned long __ffs(unsigned long word) |
| 320 | { |
| 321 | __asm__("bsfl %1,%0" |
| 322 | :"=r" (word) |
| 323 | :"rm" (word)); |
| 324 | return word; |
| 325 | } |
| 326 | |
| 327 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 328 | * find_first_bit - find the first set bit in a memory region |
| 329 | * @addr: The address to start the search at |
| 330 | * @size: The maximum size to search |
| 331 | * |
| 332 | * Returns the bit-number of the first set bit, not the number of the byte |
| 333 | * containing a bit. |
| 334 | */ |
David Howells | d89c145 | 2006-01-06 00:11:59 -0800 | [diff] [blame] | 335 | static inline unsigned find_first_bit(const unsigned long *addr, unsigned size) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 336 | { |
David Howells | d89c145 | 2006-01-06 00:11:59 -0800 | [diff] [blame] | 337 | unsigned x = 0; |
Linus Torvalds | d6d2a2a | 2005-07-29 11:01:22 -0400 | [diff] [blame] | 338 | |
| 339 | while (x < size) { |
| 340 | unsigned long val = *addr++; |
| 341 | if (val) |
| 342 | return __ffs(val) + x; |
Steven Rostedt | cd85c8b | 2005-07-28 08:45:06 -0400 | [diff] [blame] | 343 | x += (sizeof(*addr)<<3); |
Linus Torvalds | d6d2a2a | 2005-07-29 11:01:22 -0400 | [diff] [blame] | 344 | } |
Steven Rostedt | cd85c8b | 2005-07-28 08:45:06 -0400 | [diff] [blame] | 345 | return x; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 346 | } |
| 347 | |
| 348 | /** |
| 349 | * find_next_bit - find the first set bit in a memory region |
| 350 | * @addr: The address to base the search on |
| 351 | * @offset: The bitnumber to start searching at |
| 352 | * @size: The maximum size to search |
| 353 | */ |
| 354 | int find_next_bit(const unsigned long *addr, int size, int offset); |
| 355 | |
| 356 | /** |
| 357 | * ffz - find first zero in word. |
| 358 | * @word: The word to search |
| 359 | * |
| 360 | * Undefined if no zero exists, so code should check against ~0UL first. |
| 361 | */ |
| 362 | static inline unsigned long ffz(unsigned long word) |
| 363 | { |
| 364 | __asm__("bsfl %1,%0" |
| 365 | :"=r" (word) |
| 366 | :"r" (~word)); |
| 367 | return word; |
| 368 | } |
| 369 | |
Stephen Hemminger | 3821af2 | 2005-12-21 19:30:53 -0800 | [diff] [blame] | 370 | #define fls64(x) generic_fls64(x) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 371 | |
| 372 | #ifdef __KERNEL__ |
| 373 | |
| 374 | /* |
| 375 | * Every architecture must define this function. It's the fastest |
| 376 | * way of searching a 140-bit bitmap where the first 100 bits are |
| 377 | * unlikely to be set. It's guaranteed that at least one of the 140 |
| 378 | * bits is cleared. |
| 379 | */ |
| 380 | static inline int sched_find_first_bit(const unsigned long *b) |
| 381 | { |
| 382 | if (unlikely(b[0])) |
| 383 | return __ffs(b[0]); |
| 384 | if (unlikely(b[1])) |
| 385 | return __ffs(b[1]) + 32; |
| 386 | if (unlikely(b[2])) |
| 387 | return __ffs(b[2]) + 64; |
| 388 | if (b[3]) |
| 389 | return __ffs(b[3]) + 96; |
| 390 | return __ffs(b[4]) + 128; |
| 391 | } |
| 392 | |
| 393 | /** |
| 394 | * ffs - find first bit set |
| 395 | * @x: the word to search |
| 396 | * |
| 397 | * This is defined the same way as |
| 398 | * the libc and compiler builtin ffs routines, therefore |
| 399 | * differs in spirit from the above ffz (man ffs). |
| 400 | */ |
| 401 | static inline int ffs(int x) |
| 402 | { |
| 403 | int r; |
| 404 | |
| 405 | __asm__("bsfl %1,%0\n\t" |
| 406 | "jnz 1f\n\t" |
| 407 | "movl $-1,%0\n" |
| 408 | "1:" : "=r" (r) : "rm" (x)); |
| 409 | return r+1; |
| 410 | } |
| 411 | |
| 412 | /** |
Stephen Hemminger | d832245 | 2006-01-06 00:12:12 -0800 | [diff] [blame] | 413 | * fls - find last bit set |
| 414 | * @x: the word to search |
| 415 | * |
| 416 | * This is defined the same way as ffs. |
| 417 | */ |
| 418 | static inline int fls(int x) |
| 419 | { |
| 420 | int r; |
| 421 | |
| 422 | __asm__("bsrl %1,%0\n\t" |
| 423 | "jnz 1f\n\t" |
| 424 | "movl $-1,%0\n" |
| 425 | "1:" : "=r" (r) : "rm" (x)); |
| 426 | return r+1; |
| 427 | } |
| 428 | |
| 429 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 430 | * hweightN - returns the hamming weight of a N-bit word |
| 431 | * @x: the word to weigh |
| 432 | * |
| 433 | * The Hamming Weight of a number is the total number of bits set in it. |
| 434 | */ |
| 435 | |
| 436 | #define hweight32(x) generic_hweight32(x) |
| 437 | #define hweight16(x) generic_hweight16(x) |
| 438 | #define hweight8(x) generic_hweight8(x) |
| 439 | |
| 440 | #endif /* __KERNEL__ */ |
| 441 | |
| 442 | #ifdef __KERNEL__ |
| 443 | |
| 444 | #define ext2_set_bit(nr,addr) \ |
| 445 | __test_and_set_bit((nr),(unsigned long*)addr) |
| 446 | #define ext2_set_bit_atomic(lock,nr,addr) \ |
| 447 | test_and_set_bit((nr),(unsigned long*)addr) |
| 448 | #define ext2_clear_bit(nr, addr) \ |
| 449 | __test_and_clear_bit((nr),(unsigned long*)addr) |
| 450 | #define ext2_clear_bit_atomic(lock,nr, addr) \ |
| 451 | test_and_clear_bit((nr),(unsigned long*)addr) |
| 452 | #define ext2_test_bit(nr, addr) test_bit((nr),(unsigned long*)addr) |
| 453 | #define ext2_find_first_zero_bit(addr, size) \ |
| 454 | find_first_zero_bit((unsigned long*)addr, size) |
| 455 | #define ext2_find_next_zero_bit(addr, size, off) \ |
| 456 | find_next_zero_bit((unsigned long*)addr, size, off) |
| 457 | |
| 458 | /* Bitmap functions for the minix filesystem. */ |
| 459 | #define minix_test_and_set_bit(nr,addr) __test_and_set_bit(nr,(void*)addr) |
| 460 | #define minix_set_bit(nr,addr) __set_bit(nr,(void*)addr) |
| 461 | #define minix_test_and_clear_bit(nr,addr) __test_and_clear_bit(nr,(void*)addr) |
| 462 | #define minix_test_bit(nr,addr) test_bit(nr,(void*)addr) |
| 463 | #define minix_find_first_zero_bit(addr,size) \ |
| 464 | find_first_zero_bit((void*)addr,size) |
| 465 | |
| 466 | #endif /* __KERNEL__ */ |
| 467 | |
| 468 | #endif /* _I386_BITOPS_H */ |