1 #ifndef _I386_BITOPS_H 2 #define _I386_BITOPS_H 3 4 /* 5 * Copyright 1992, Linus Torvalds. 6 */ 7 8 9 /* 10 * These have to be done with inline assembly: that way the bit-setting 11 * is guaranteed to be atomic. All bit operations return 0 if the bit 12 * was cleared before the operation and != 0 if it was not. 13 * 14 * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1). 15 */ 16 17 #include <asm-generic/bitops/fls.h> 18 #include <asm-generic/bitops/__fls.h> 19 #include <asm-generic/bitops/fls64.h> 20 21 #ifdef CONFIG_SMP 22 #define LOCK_PREFIX "lock ; " 23 #else 24 #define LOCK_PREFIX "" 25 #endif 26 27 #define ADDR (*(volatile long *) 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 static __inline__ void set_bit(int nr, volatile void * addr) 40 { 41 __asm__ __volatile__( LOCK_PREFIX 42 "btsl %1,%0" 43 :"=m" (ADDR) 44 :"Ir" (nr)); 45 } 46 47 /** 48 * __set_bit - Set a bit in memory 49 * @nr: the bit to set 50 * @addr: the address to start counting from 51 * 52 * Unlike set_bit(), this function is non-atomic and may be reordered. 53 * If it's called on the same region of memory simultaneously, the effect 54 * may be that only one operation succeeds. 55 */ 56 static __inline__ void __set_bit(int nr, volatile void * addr) 57 { 58 __asm__( 59 "btsl %1,%0" 60 :"=m" (ADDR) 61 :"Ir" (nr)); 62 } 63 64 /** 65 * clear_bit - Clears a bit in memory 66 * @nr: Bit to clear 67 * @addr: Address to start counting from 68 * 69 * clear_bit() is atomic and may not be reordered. However, it does 70 * not contain a memory barrier, so if it is used for locking purposes, 71 * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit() 72 * in order to ensure changes are visible on other processors. 73 */ 74 static __inline__ void clear_bit(int nr, volatile void * addr) 75 { 76 __asm__ __volatile__( LOCK_PREFIX 77 "btrl %1,%0" 78 :"=m" (ADDR) 79 :"Ir" (nr)); 80 } 81 #define smp_mb__before_clear_bit() barrier() 82 #define smp_mb__after_clear_bit() barrier() 83 84 /** 85 * __change_bit - Toggle a bit in memory 86 * @nr: the bit to set 87 * @addr: the address to start counting from 88 * 89 * Unlike change_bit(), this function is non-atomic and may be reordered. 90 * If it's called on the same region of memory simultaneously, the effect 91 * may be that only one operation succeeds. 92 */ 93 static __inline__ void __change_bit(int nr, volatile void * addr) 94 { 95 __asm__ __volatile__( 96 "btcl %1,%0" 97 :"=m" (ADDR) 98 :"Ir" (nr)); 99 } 100 101 /** 102 * change_bit - Toggle a bit in memory 103 * @nr: Bit to clear 104 * @addr: Address to start counting from 105 * 106 * change_bit() is atomic and may not be reordered. 107 * Note that @nr may be almost arbitrarily large; this function is not 108 * restricted to acting on a single-word quantity. 109 */ 110 static __inline__ void change_bit(int nr, volatile void * addr) 111 { 112 __asm__ __volatile__( LOCK_PREFIX 113 "btcl %1,%0" 114 :"=m" (ADDR) 115 :"Ir" (nr)); 116 } 117 118 /** 119 * test_and_set_bit - Set a bit and return its old value 120 * @nr: Bit to set 121 * @addr: Address to count from 122 * 123 * This operation is atomic and cannot be reordered. 124 * It also implies a memory barrier. 125 */ 126 static __inline__ int test_and_set_bit(int nr, volatile void * addr) 127 { 128 int oldbit; 129 130 __asm__ __volatile__( LOCK_PREFIX 131 "btsl %2,%1\n\tsbbl %0,%0" 132 :"=r" (oldbit),"=m" (ADDR) 133 :"Ir" (nr) : "memory"); 134 return oldbit; 135 } 136 137 /** 138 * __test_and_set_bit - Set a bit and return its old value 139 * @nr: Bit to set 140 * @addr: Address to count from 141 * 142 * This operation is non-atomic and can be reordered. 143 * If two examples of this operation race, one can appear to succeed 144 * but actually fail. You must protect multiple accesses with a lock. 145 */ 146 static __inline__ int __test_and_set_bit(int nr, volatile void * addr) 147 { 148 int oldbit; 149 150 __asm__( 151 "btsl %2,%1\n\tsbbl %0,%0" 152 :"=r" (oldbit),"=m" (ADDR) 153 :"Ir" (nr)); 154 return oldbit; 155 } 156 157 /** 158 * test_and_clear_bit - Clear a bit and return its old value 159 * @nr: Bit to set 160 * @addr: Address to count from 161 * 162 * This operation is atomic and cannot be reordered. 163 * It also implies a memory barrier. 164 */ 165 static __inline__ int test_and_clear_bit(int nr, volatile void * addr) 166 { 167 int oldbit; 168 169 __asm__ __volatile__( LOCK_PREFIX 170 "btrl %2,%1\n\tsbbl %0,%0" 171 :"=r" (oldbit),"=m" (ADDR) 172 :"Ir" (nr) : "memory"); 173 return oldbit; 174 } 175 176 /** 177 * __test_and_clear_bit - Clear a bit and return its old value 178 * @nr: Bit to set 179 * @addr: Address to count from 180 * 181 * This operation is non-atomic and can be reordered. 182 * If two examples of this operation race, one can appear to succeed 183 * but actually fail. You must protect multiple accesses with a lock. 184 */ 185 static __inline__ int __test_and_clear_bit(int nr, volatile void * addr) 186 { 187 int oldbit; 188 189 __asm__( 190 "btrl %2,%1\n\tsbbl %0,%0" 191 :"=r" (oldbit),"=m" (ADDR) 192 :"Ir" (nr)); 193 return oldbit; 194 } 195 196 /* WARNING: non atomic and it can be reordered! */ 197 static __inline__ int __test_and_change_bit(int nr, volatile void * addr) 198 { 199 int oldbit; 200 201 __asm__ __volatile__( 202 "btcl %2,%1\n\tsbbl %0,%0" 203 :"=r" (oldbit),"=m" (ADDR) 204 :"Ir" (nr) : "memory"); 205 return oldbit; 206 } 207 208 /** 209 * test_and_change_bit - Change a bit and return its new value 210 * @nr: Bit to set 211 * @addr: Address to count from 212 * 213 * This operation is atomic and cannot be reordered. 214 * It also implies a memory barrier. 215 */ 216 static __inline__ int test_and_change_bit(int nr, volatile void * addr) 217 { 218 int oldbit; 219 220 __asm__ __volatile__( LOCK_PREFIX 221 "btcl %2,%1\n\tsbbl %0,%0" 222 :"=r" (oldbit),"=m" (ADDR) 223 :"Ir" (nr) : "memory"); 224 return oldbit; 225 } 226 227 #if 0 /* Fool kernel-doc since it doesn't do macros yet */ 228 /** 229 * test_bit - Determine whether a bit is set 230 * @nr: bit number to test 231 * @addr: Address to start counting from 232 */ 233 static int test_bit(int nr, const volatile void * addr); 234 #endif 235 236 static __inline__ int constant_test_bit(int nr, const volatile void * addr) 237 { 238 return ((1UL << (nr & 31)) & (((const volatile unsigned int *) addr)[nr >> 5])) != 0; 239 } 240 241 static __inline__ int variable_test_bit(int nr, volatile void * addr) 242 { 243 int oldbit; 244 245 __asm__ __volatile__( 246 "btl %2,%1\n\tsbbl %0,%0" 247 :"=r" (oldbit) 248 :"m" (ADDR),"Ir" (nr)); 249 return oldbit; 250 } 251 252 #define test_bit(nr,addr) \ 253 (__builtin_constant_p(nr) ? \ 254 constant_test_bit((nr),(addr)) : \ 255 variable_test_bit((nr),(addr))) 256 257 /** 258 * find_first_zero_bit - find the first zero bit in a memory region 259 * @addr: The address to start the search at 260 * @size: The maximum size to search 261 * 262 * Returns the bit-number of the first zero bit, not the number of the byte 263 * containing a bit. 264 */ 265 static __inline__ int find_first_zero_bit(void * addr, unsigned size) 266 { 267 int d0, d1, d2; 268 int res; 269 270 if (!size) 271 return 0; 272 /* This looks at memory. Mark it volatile to tell gcc not to move it around */ 273 __asm__ __volatile__( 274 "movl $-1,%%eax\n\t" 275 "xorl %%edx,%%edx\n\t" 276 "repe; scasl\n\t" 277 "je 1f\n\t" 278 "xorl -4(%%edi),%%eax\n\t" 279 "subl $4,%%edi\n\t" 280 "bsfl %%eax,%%edx\n" 281 "1:\tsubl %%ebx,%%edi\n\t" 282 "shll $3,%%edi\n\t" 283 "addl %%edi,%%edx" 284 :"=d" (res), "=&c" (d0), "=&D" (d1), "=&a" (d2) 285 :"1" ((size + 31) >> 5), "2" (addr), "b" (addr)); 286 return res; 287 } 288 289 /** 290 * find_next_zero_bit - find the first zero bit in a memory region 291 * @addr: The address to base the search on 292 * @offset: The bitnumber to start searching at 293 * @size: The maximum size to search 294 */ 295 static __inline__ int find_next_zero_bit (void * addr, int size, int offset) 296 { 297 unsigned long * p = ((unsigned long *) addr) + (offset >> 5); 298 int set = 0, bit = offset & 31, res; 299 300 if (bit) { 301 /* 302 * Look for zero in first byte 303 */ 304 __asm__("bsfl %1,%0\n\t" 305 "jne 1f\n\t" 306 "movl $32, %0\n" 307 "1:" 308 : "=r" (set) 309 : "r" (~(*p >> bit))); 310 if (set < (32 - bit)) 311 return set + offset; 312 set = 32 - bit; 313 p++; 314 } 315 /* 316 * No zero yet, search remaining full bytes for a zero 317 */ 318 res = find_first_zero_bit (p, size - 32 * (p - (unsigned long *) addr)); 319 return (offset + set + res); 320 } 321 322 /** 323 * ffz - find first zero in word. 324 * @word: The word to search 325 * 326 * Undefined if no zero exists, so code should check against ~0UL first. 327 */ 328 static __inline__ unsigned long ffz(unsigned long word) 329 { 330 __asm__("bsfl %1,%0" 331 :"=r" (word) 332 :"r" (~word)); 333 return word; 334 } 335 336 #ifdef __KERNEL__ 337 338 /** 339 * __ffs - find first set bit in word 340 * @word: The word to search 341 * 342 * Undefined if no bit exists, so code should check against 0 first. 343 */ 344 static inline unsigned long __ffs(unsigned long word) 345 { 346 __asm__("rep; bsf %1,%0" 347 : "=r" (word) 348 : "rm" (word)); 349 return word; 350 } 351 352 /** 353 * ffs - find first bit set 354 * @x: the word to search 355 * 356 * This is defined the same way as 357 * the libc and compiler builtin ffs routines, therefore 358 * differs in spirit from the above ffz (man ffs). 359 */ 360 static __inline__ int ffs(int x) 361 { 362 int r; 363 364 __asm__("bsfl %1,%0\n\t" 365 "jnz 1f\n\t" 366 "movl $-1,%0\n" 367 "1:" : "=r" (r) : "rm" (x)); 368 369 return r+1; 370 } 371 #define PLATFORM_FFS 372 373 static inline int __ilog2(unsigned int x) 374 { 375 return generic_fls(x) - 1; 376 } 377 378 /** 379 * hweightN - returns the hamming weight of a N-bit word 380 * @x: the word to weigh 381 * 382 * The Hamming Weight of a number is the total number of bits set in it. 383 */ 384 385 #define hweight32(x) generic_hweight32(x) 386 #define hweight16(x) generic_hweight16(x) 387 #define hweight8(x) generic_hweight8(x) 388 389 #endif /* __KERNEL__ */ 390 391 #ifdef __KERNEL__ 392 393 #define ext2_set_bit __test_and_set_bit 394 #define ext2_clear_bit __test_and_clear_bit 395 #define ext2_test_bit test_bit 396 #define ext2_find_first_zero_bit find_first_zero_bit 397 #define ext2_find_next_zero_bit find_next_zero_bit 398 399 /* Bitmap functions for the minix filesystem. */ 400 #define minix_test_and_set_bit(nr,addr) __test_and_set_bit(nr,addr) 401 #define minix_set_bit(nr,addr) __set_bit(nr,addr) 402 #define minix_test_and_clear_bit(nr,addr) __test_and_clear_bit(nr,addr) 403 #define minix_test_bit(nr,addr) test_bit(nr,addr) 404 #define minix_find_first_zero_bit(addr,size) find_first_zero_bit(addr,size) 405 406 #endif /* __KERNEL__ */ 407 408 #endif /* _I386_BITOPS_H */ 409