1 /* 2 * This file is subject to the terms and conditions of the GNU General Public 3 * License. See the file "COPYING" in the main directory of this archive 4 * for more details. 5 * 6 * Copyright (c) 1994 - 1997, 1999, 2000 Ralf Baechle (ralf@gnu.org) 7 * Copyright (c) 2000 Silicon Graphics, Inc. 8 */ 9 #ifndef _ASM_BITOPS_H 10 #define _ASM_BITOPS_H 11 12 #include <linux/types.h> 13 #include <asm/byteorder.h> /* sigh ... */ 14 15 #ifdef __KERNEL__ 16 17 #include <asm/sgidefs.h> 18 #include <asm/system.h> 19 #include <linux/config.h> 20 21 /* 22 * clear_bit() doesn't provide any barrier for the compiler. 23 */ 24 #define smp_mb__before_clear_bit() barrier() 25 #define smp_mb__after_clear_bit() barrier() 26 27 /* 28 * Only disable interrupt for kernel mode stuff to keep usermode stuff 29 * that dares to use kernel include files alive. 30 */ 31 #define __bi_flags unsigned long flags 32 #define __bi_cli() __cli() 33 #define __bi_save_flags(x) __save_flags(x) 34 #define __bi_save_and_cli(x) __save_and_cli(x) 35 #define __bi_restore_flags(x) __restore_flags(x) 36 #else 37 #define __bi_flags 38 #define __bi_cli() 39 #define __bi_save_flags(x) 40 #define __bi_save_and_cli(x) 41 #define __bi_restore_flags(x) 42 #endif /* __KERNEL__ */ 43 44 #ifdef CONFIG_CPU_HAS_LLSC 45 46 #include <asm/mipsregs.h> 47 48 /* 49 * These functions for MIPS ISA > 1 are interrupt and SMP proof and 50 * interrupt friendly 51 */ 52 53 /* 54 * set_bit - Atomically set a bit in memory 55 * @nr: the bit to set 56 * @addr: the address to start counting from 57 * 58 * This function is atomic and may not be reordered. See __set_bit() 59 * if you do not require the atomic guarantees. 60 * Note that @nr may be almost arbitrarily large; this function is not 61 * restricted to acting on a single-word quantity. 62 */ 63 static __inline__ void 64 set_bit(int nr, volatile void *addr) 65 { 66 unsigned long *m = ((unsigned long *) addr) + (nr >> 5); 67 unsigned long temp; 68 69 __asm__ __volatile__( 70 "1:\tll\t%0, %1\t\t# set_bit\n\t" 71 "or\t%0, %2\n\t" 72 "sc\t%0, %1\n\t" 73 "beqz\t%0, 1b" 74 : "=&r" (temp), "=m" (*m) 75 : "ir" (1UL << (nr & 0x1f)), "m" (*m)); 76 } 77 78 /* 79 * __set_bit - Set a bit in memory 80 * @nr: the bit to set 81 * @addr: the address to start counting from 82 * 83 * Unlike set_bit(), this function is non-atomic and may be reordered. 84 * If it's called on the same region of memory simultaneously, the effect 85 * may be that only one operation succeeds. 86 */ 87 static __inline__ void __set_bit(int nr, volatile void * addr) 88 { 89 unsigned long * m = ((unsigned long *) addr) + (nr >> 5); 90 91 *m |= 1UL << (nr & 31); 92 } 93 #define PLATFORM__SET_BIT 94 95 /* 96 * clear_bit - Clears a bit in memory 97 * @nr: Bit to clear 98 * @addr: Address to start counting from 99 * 100 * clear_bit() is atomic and may not be reordered. However, it does 101 * not contain a memory barrier, so if it is used for locking purposes, 102 * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit() 103 * in order to ensure changes are visible on other processors. 104 */ 105 static __inline__ void 106 clear_bit(int nr, volatile void *addr) 107 { 108 unsigned long *m = ((unsigned long *) addr) + (nr >> 5); 109 unsigned long temp; 110 111 __asm__ __volatile__( 112 "1:\tll\t%0, %1\t\t# clear_bit\n\t" 113 "and\t%0, %2\n\t" 114 "sc\t%0, %1\n\t" 115 "beqz\t%0, 1b\n\t" 116 : "=&r" (temp), "=m" (*m) 117 : "ir" (~(1UL << (nr & 0x1f))), "m" (*m)); 118 } 119 120 /* 121 * change_bit - Toggle a bit in memory 122 * @nr: Bit to clear 123 * @addr: Address to start counting from 124 * 125 * change_bit() is atomic and may not be reordered. 126 * Note that @nr may be almost arbitrarily large; this function is not 127 * restricted to acting on a single-word quantity. 128 */ 129 static __inline__ void 130 change_bit(int nr, volatile void *addr) 131 { 132 unsigned long *m = ((unsigned long *) addr) + (nr >> 5); 133 unsigned long temp; 134 135 __asm__ __volatile__( 136 "1:\tll\t%0, %1\t\t# change_bit\n\t" 137 "xor\t%0, %2\n\t" 138 "sc\t%0, %1\n\t" 139 "beqz\t%0, 1b" 140 : "=&r" (temp), "=m" (*m) 141 : "ir" (1UL << (nr & 0x1f)), "m" (*m)); 142 } 143 144 /* 145 * __change_bit - Toggle a bit in memory 146 * @nr: the bit to set 147 * @addr: the address to start counting from 148 * 149 * Unlike change_bit(), this function is non-atomic and may be reordered. 150 * If it's called on the same region of memory simultaneously, the effect 151 * may be that only one operation succeeds. 152 */ 153 static __inline__ void __change_bit(int nr, volatile void * addr) 154 { 155 unsigned long * m = ((unsigned long *) addr) + (nr >> 5); 156 157 *m ^= 1UL << (nr & 31); 158 } 159 160 /* 161 * test_and_set_bit - Set a bit and return its old value 162 * @nr: Bit to set 163 * @addr: Address to count from 164 * 165 * This operation is atomic and cannot be reordered. 166 * It also implies a memory barrier. 167 */ 168 static __inline__ int 169 test_and_set_bit(int nr, volatile void *addr) 170 { 171 unsigned long *m = ((unsigned long *) addr) + (nr >> 5); 172 unsigned long temp, res; 173 174 __asm__ __volatile__( 175 ".set\tnoreorder\t\t# test_and_set_bit\n" 176 "1:\tll\t%0, %1\n\t" 177 "or\t%2, %0, %3\n\t" 178 "sc\t%2, %1\n\t" 179 "beqz\t%2, 1b\n\t" 180 " and\t%2, %0, %3\n\t" 181 ".set\treorder" 182 : "=&r" (temp), "=m" (*m), "=&r" (res) 183 : "r" (1UL << (nr & 0x1f)), "m" (*m) 184 : "memory"); 185 186 return res != 0; 187 } 188 189 /* 190 * __test_and_set_bit - Set a bit and return its old value 191 * @nr: Bit to set 192 * @addr: Address to count from 193 * 194 * This operation is non-atomic and can be reordered. 195 * If two examples of this operation race, one can appear to succeed 196 * but actually fail. You must protect multiple accesses with a lock. 197 */ 198 static __inline__ int __test_and_set_bit(int nr, volatile void * addr) 199 { 200 int mask, retval; 201 volatile int *a = addr; 202 203 a += nr >> 5; 204 mask = 1 << (nr & 0x1f); 205 retval = (mask & *a) != 0; 206 *a |= mask; 207 208 return retval; 209 } 210 211 /* 212 * test_and_clear_bit - Clear a bit and return its old value 213 * @nr: Bit to set 214 * @addr: Address to count from 215 * 216 * This operation is atomic and cannot be reordered. 217 * It also implies a memory barrier. 218 */ 219 static __inline__ int 220 test_and_clear_bit(int nr, volatile void *addr) 221 { 222 unsigned long *m = ((unsigned long *) addr) + (nr >> 5); 223 unsigned long temp, res; 224 225 __asm__ __volatile__( 226 ".set\tnoreorder\t\t# test_and_clear_bit\n" 227 "1:\tll\t%0, %1\n\t" 228 "or\t%2, %0, %3\n\t" 229 "xor\t%2, %3\n\t" 230 "sc\t%2, %1\n\t" 231 "beqz\t%2, 1b\n\t" 232 " and\t%2, %0, %3\n\t" 233 ".set\treorder" 234 : "=&r" (temp), "=m" (*m), "=&r" (res) 235 : "r" (1UL << (nr & 0x1f)), "m" (*m) 236 : "memory"); 237 238 return res != 0; 239 } 240 241 /* 242 * __test_and_clear_bit - Clear a bit and return its old value 243 * @nr: Bit to set 244 * @addr: Address to count from 245 * 246 * This operation is non-atomic and can be reordered. 247 * If two examples of this operation race, one can appear to succeed 248 * but actually fail. You must protect multiple accesses with a lock. 249 */ 250 static __inline__ int __test_and_clear_bit(int nr, volatile void * addr) 251 { 252 int mask, retval; 253 volatile int *a = addr; 254 255 a += nr >> 5; 256 mask = 1 << (nr & 0x1f); 257 retval = (mask & *a) != 0; 258 *a &= ~mask; 259 260 return retval; 261 } 262 263 /* 264 * test_and_change_bit - Change a bit and return its new value 265 * @nr: Bit to set 266 * @addr: Address to count from 267 * 268 * This operation is atomic and cannot be reordered. 269 * It also implies a memory barrier. 270 */ 271 static __inline__ int 272 test_and_change_bit(int nr, volatile void *addr) 273 { 274 unsigned long *m = ((unsigned long *) addr) + (nr >> 5); 275 unsigned long temp, res; 276 277 __asm__ __volatile__( 278 ".set\tnoreorder\t\t# test_and_change_bit\n" 279 "1:\tll\t%0, %1\n\t" 280 "xor\t%2, %0, %3\n\t" 281 "sc\t%2, %1\n\t" 282 "beqz\t%2, 1b\n\t" 283 " and\t%2, %0, %3\n\t" 284 ".set\treorder" 285 : "=&r" (temp), "=m" (*m), "=&r" (res) 286 : "r" (1UL << (nr & 0x1f)), "m" (*m) 287 : "memory"); 288 289 return res != 0; 290 } 291 292 /* 293 * __test_and_change_bit - Change a bit and return its old value 294 * @nr: Bit to set 295 * @addr: Address to count from 296 * 297 * This operation is non-atomic and can be reordered. 298 * If two examples of this operation race, one can appear to succeed 299 * but actually fail. You must protect multiple accesses with a lock. 300 */ 301 static __inline__ int __test_and_change_bit(int nr, volatile void * addr) 302 { 303 int mask, retval; 304 volatile int *a = addr; 305 306 a += nr >> 5; 307 mask = 1 << (nr & 0x1f); 308 retval = (mask & *a) != 0; 309 *a ^= mask; 310 311 return retval; 312 } 313 314 #else /* MIPS I */ 315 316 /* 317 * set_bit - Atomically set a bit in memory 318 * @nr: the bit to set 319 * @addr: the address to start counting from 320 * 321 * This function is atomic and may not be reordered. See __set_bit() 322 * if you do not require the atomic guarantees. 323 * Note that @nr may be almost arbitrarily large; this function is not 324 * restricted to acting on a single-word quantity. 325 */ 326 static __inline__ void set_bit(int nr, volatile void * addr) 327 { 328 int mask; 329 volatile int *a = addr; 330 __bi_flags; 331 332 a += nr >> 5; 333 mask = 1 << (nr & 0x1f); 334 __bi_save_and_cli(flags); 335 *a |= mask; 336 __bi_restore_flags(flags); 337 } 338 339 /* 340 * __set_bit - Set a bit in memory 341 * @nr: the bit to set 342 * @addr: the address to start counting from 343 * 344 * Unlike set_bit(), this function is non-atomic and may be reordered. 345 * If it's called on the same region of memory simultaneously, the effect 346 * may be that only one operation succeeds. 347 */ 348 static __inline__ void __set_bit(int nr, volatile void * addr) 349 { 350 int mask; 351 volatile int *a = addr; 352 353 a += nr >> 5; 354 mask = 1 << (nr & 0x1f); 355 *a |= mask; 356 } 357 358 /* 359 * clear_bit - Clears a bit in memory 360 * @nr: Bit to clear 361 * @addr: Address to start counting from 362 * 363 * clear_bit() is atomic and may not be reordered. However, it does 364 * not contain a memory barrier, so if it is used for locking purposes, 365 * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit() 366 * in order to ensure changes are visible on other processors. 367 */ 368 static __inline__ void clear_bit(int nr, volatile void * addr) 369 { 370 int mask; 371 volatile int *a = addr; 372 __bi_flags; 373 374 a += nr >> 5; 375 mask = 1 << (nr & 0x1f); 376 __bi_save_and_cli(flags); 377 *a &= ~mask; 378 __bi_restore_flags(flags); 379 } 380 381 /* 382 * change_bit - Toggle a bit in memory 383 * @nr: Bit to clear 384 * @addr: Address to start counting from 385 * 386 * change_bit() is atomic and may not be reordered. 387 * Note that @nr may be almost arbitrarily large; this function is not 388 * restricted to acting on a single-word quantity. 389 */ 390 static __inline__ void change_bit(int nr, volatile void * addr) 391 { 392 int mask; 393 volatile int *a = addr; 394 __bi_flags; 395 396 a += nr >> 5; 397 mask = 1 << (nr & 0x1f); 398 __bi_save_and_cli(flags); 399 *a ^= mask; 400 __bi_restore_flags(flags); 401 } 402 403 /* 404 * __change_bit - Toggle a bit in memory 405 * @nr: the bit to set 406 * @addr: the address to start counting from 407 * 408 * Unlike change_bit(), this function is non-atomic and may be reordered. 409 * If it's called on the same region of memory simultaneously, the effect 410 * may be that only one operation succeeds. 411 */ 412 static __inline__ void __change_bit(int nr, volatile void * addr) 413 { 414 unsigned long * m = ((unsigned long *) addr) + (nr >> 5); 415 416 *m ^= 1UL << (nr & 31); 417 } 418 419 /* 420 * test_and_set_bit - Set a bit and return its old value 421 * @nr: Bit to set 422 * @addr: Address to count from 423 * 424 * This operation is atomic and cannot be reordered. 425 * It also implies a memory barrier. 426 */ 427 static __inline__ int test_and_set_bit(int nr, volatile void * addr) 428 { 429 int mask, retval; 430 volatile int *a = addr; 431 __bi_flags; 432 433 a += nr >> 5; 434 mask = 1 << (nr & 0x1f); 435 __bi_save_and_cli(flags); 436 retval = (mask & *a) != 0; 437 *a |= mask; 438 __bi_restore_flags(flags); 439 440 return retval; 441 } 442 443 /* 444 * __test_and_set_bit - Set a bit and return its old value 445 * @nr: Bit to set 446 * @addr: Address to count from 447 * 448 * This operation is non-atomic and can be reordered. 449 * If two examples of this operation race, one can appear to succeed 450 * but actually fail. You must protect multiple accesses with a lock. 451 */ 452 static __inline__ int __test_and_set_bit(int nr, volatile void * addr) 453 { 454 int mask, retval; 455 volatile int *a = addr; 456 457 a += nr >> 5; 458 mask = 1 << (nr & 0x1f); 459 retval = (mask & *a) != 0; 460 *a |= mask; 461 462 return retval; 463 } 464 465 /* 466 * test_and_clear_bit - Clear a bit and return its old value 467 * @nr: Bit to set 468 * @addr: Address to count from 469 * 470 * This operation is atomic and cannot be reordered. 471 * It also implies a memory barrier. 472 */ 473 static __inline__ int test_and_clear_bit(int nr, volatile void * addr) 474 { 475 int mask, retval; 476 volatile int *a = addr; 477 __bi_flags; 478 479 a += nr >> 5; 480 mask = 1 << (nr & 0x1f); 481 __bi_save_and_cli(flags); 482 retval = (mask & *a) != 0; 483 *a &= ~mask; 484 __bi_restore_flags(flags); 485 486 return retval; 487 } 488 489 /* 490 * __test_and_clear_bit - Clear a bit and return its old value 491 * @nr: Bit to set 492 * @addr: Address to count from 493 * 494 * This operation is non-atomic and can be reordered. 495 * If two examples of this operation race, one can appear to succeed 496 * but actually fail. You must protect multiple accesses with a lock. 497 */ 498 static __inline__ int __test_and_clear_bit(int nr, volatile void * addr) 499 { 500 int mask, retval; 501 volatile int *a = addr; 502 503 a += nr >> 5; 504 mask = 1 << (nr & 0x1f); 505 retval = (mask & *a) != 0; 506 *a &= ~mask; 507 508 return retval; 509 } 510 511 /* 512 * test_and_change_bit - Change a bit and return its new value 513 * @nr: Bit to set 514 * @addr: Address to count from 515 * 516 * This operation is atomic and cannot be reordered. 517 * It also implies a memory barrier. 518 */ 519 static __inline__ int test_and_change_bit(int nr, volatile void * addr) 520 { 521 int mask, retval; 522 volatile int *a = addr; 523 __bi_flags; 524 525 a += nr >> 5; 526 mask = 1 << (nr & 0x1f); 527 __bi_save_and_cli(flags); 528 retval = (mask & *a) != 0; 529 *a ^= mask; 530 __bi_restore_flags(flags); 531 532 return retval; 533 } 534 535 /* 536 * __test_and_change_bit - Change a bit and return its old value 537 * @nr: Bit to set 538 * @addr: Address to count from 539 * 540 * This operation is non-atomic and can be reordered. 541 * If two examples of this operation race, one can appear to succeed 542 * but actually fail. You must protect multiple accesses with a lock. 543 */ 544 static __inline__ int __test_and_change_bit(int nr, volatile void * addr) 545 { 546 int mask, retval; 547 volatile int *a = addr; 548 549 a += nr >> 5; 550 mask = 1 << (nr & 0x1f); 551 retval = (mask & *a) != 0; 552 *a ^= mask; 553 554 return retval; 555 } 556 557 #undef __bi_flags 558 #undef __bi_cli 559 #undef __bi_save_flags 560 #undef __bi_restore_flags 561 562 #endif /* MIPS I */ 563 564 /* 565 * test_bit - Determine whether a bit is set 566 * @nr: bit number to test 567 * @addr: Address to start counting from 568 */ 569 static __inline__ int test_bit(int nr, volatile void *addr) 570 { 571 return ((1UL << (nr & 31)) & (((const unsigned int *) addr)[nr >> 5])) != 0; 572 } 573 574 #ifndef __MIPSEB__ 575 576 /* Little endian versions. */ 577 578 /* 579 * find_first_zero_bit - find the first zero bit in a memory region 580 * @addr: The address to start the search at 581 * @size: The maximum size to search 582 * 583 * Returns the bit-number of the first zero bit, not the number of the byte 584 * containing a bit. 585 */ 586 static __inline__ int find_first_zero_bit (void *addr, unsigned size) 587 { 588 unsigned long dummy; 589 int res; 590 591 if (!size) 592 return 0; 593 594 __asm__ (".set\tnoreorder\n\t" 595 ".set\tnoat\n" 596 "1:\tsubu\t$1,%6,%0\n\t" 597 "blez\t$1,2f\n\t" 598 "lw\t$1,(%5)\n\t" 599 "addiu\t%5,4\n\t" 600 #if (_MIPS_ISA == _MIPS_ISA_MIPS2 ) || (_MIPS_ISA == _MIPS_ISA_MIPS3 ) || \ 601 (_MIPS_ISA == _MIPS_ISA_MIPS4 ) || (_MIPS_ISA == _MIPS_ISA_MIPS5 ) || \ 602 (_MIPS_ISA == _MIPS_ISA_MIPS32) || (_MIPS_ISA == _MIPS_ISA_MIPS64) 603 "beql\t%1,$1,1b\n\t" 604 "addiu\t%0,32\n\t" 605 #else 606 "addiu\t%0,32\n\t" 607 "beq\t%1,$1,1b\n\t" 608 "nop\n\t" 609 "subu\t%0,32\n\t" 610 #endif 611 #ifdef __MIPSEB__ 612 #error "Fix this for big endian" 613 #endif /* __MIPSEB__ */ 614 "li\t%1,1\n" 615 "1:\tand\t%2,$1,%1\n\t" 616 "beqz\t%2,2f\n\t" 617 "sll\t%1,%1,1\n\t" 618 "bnez\t%1,1b\n\t" 619 "add\t%0,%0,1\n\t" 620 ".set\tat\n\t" 621 ".set\treorder\n" 622 "2:" 623 : "=r" (res), "=r" (dummy), "=r" (addr) 624 : "0" ((signed int) 0), "1" ((unsigned int) 0xffffffff), 625 "2" (addr), "r" (size) 626 : "$1"); 627 628 return res; 629 } 630 631 /* 632 * find_next_zero_bit - find the first zero bit in a memory region 633 * @addr: The address to base the search on 634 * @offset: The bitnumber to start searching at 635 * @size: The maximum size to search 636 */ 637 static __inline__ int find_next_zero_bit (void * addr, int size, int offset) 638 { 639 unsigned int *p = ((unsigned int *) addr) + (offset >> 5); 640 int set = 0, bit = offset & 31, res; 641 unsigned long dummy; 642 643 if (bit) { 644 /* 645 * Look for zero in first byte 646 */ 647 #ifdef __MIPSEB__ 648 #error "Fix this for big endian byte order" 649 #endif 650 __asm__(".set\tnoreorder\n\t" 651 ".set\tnoat\n" 652 "1:\tand\t$1,%4,%1\n\t" 653 "beqz\t$1,1f\n\t" 654 "sll\t%1,%1,1\n\t" 655 "bnez\t%1,1b\n\t" 656 "addiu\t%0,1\n\t" 657 ".set\tat\n\t" 658 ".set\treorder\n" 659 "1:" 660 : "=r" (set), "=r" (dummy) 661 : "0" (0), "1" (1 << bit), "r" (*p) 662 : "$1"); 663 if (set < (32 - bit)) 664 return set + offset; 665 set = 32 - bit; 666 p++; 667 } 668 /* 669 * No zero yet, search remaining full bytes for a zero 670 */ 671 res = find_first_zero_bit(p, size - 32 * (p - (unsigned int *) addr)); 672 return offset + set + res; 673 } 674 675 #endif /* !(__MIPSEB__) */ 676 677 /* 678 * ffz - find first zero in word. 679 * @word: The word to search 680 * 681 * Undefined if no zero exists, so code should check against ~0UL first. 682 */ 683 static __inline__ unsigned long ffz(unsigned long word) 684 { 685 unsigned int __res; 686 unsigned int mask = 1; 687 688 __asm__ ( 689 ".set\tnoreorder\n\t" 690 ".set\tnoat\n\t" 691 "move\t%0,$0\n" 692 "1:\tand\t$1,%2,%1\n\t" 693 "beqz\t$1,2f\n\t" 694 "sll\t%1,1\n\t" 695 "bnez\t%1,1b\n\t" 696 "addiu\t%0,1\n\t" 697 ".set\tat\n\t" 698 ".set\treorder\n" 699 "2:\n\t" 700 : "=&r" (__res), "=r" (mask) 701 : "r" (word), "1" (mask) 702 : "$1"); 703 704 return __res; 705 } 706 707 #ifdef __KERNEL__ 708 709 /* 710 * hweightN - returns the hamming weight of a N-bit word 711 * @x: the word to weigh 712 * 713 * The Hamming Weight of a number is the total number of bits set in it. 714 */ 715 716 #define hweight32(x) generic_hweight32(x) 717 #define hweight16(x) generic_hweight16(x) 718 #define hweight8(x) generic_hweight8(x) 719 720 #endif /* __KERNEL__ */ 721 722 #ifdef __MIPSEB__ 723 /* 724 * find_next_zero_bit - find the first zero bit in a memory region 725 * @addr: The address to base the search on 726 * @offset: The bitnumber to start searching at 727 * @size: The maximum size to search 728 */ 729 static __inline__ int find_next_zero_bit(void *addr, int size, int offset) 730 { 731 unsigned long *p = ((unsigned long *) addr) + (offset >> 5); 732 unsigned long result = offset & ~31UL; 733 unsigned long tmp; 734 735 if (offset >= size) 736 return size; 737 size -= result; 738 offset &= 31UL; 739 if (offset) { 740 tmp = *(p++); 741 tmp |= ~0UL >> (32-offset); 742 if (size < 32) 743 goto found_first; 744 if (~tmp) 745 goto found_middle; 746 size -= 32; 747 result += 32; 748 } 749 while (size & ~31UL) { 750 if (~(tmp = *(p++))) 751 goto found_middle; 752 result += 32; 753 size -= 32; 754 } 755 if (!size) 756 return result; 757 tmp = *p; 758 759 found_first: 760 tmp |= ~0UL << size; 761 found_middle: 762 return result + ffz(tmp); 763 } 764 765 /* Linus sez that gcc can optimize the following correctly, we'll see if this 766 * holds on the Sparc as it does for the ALPHA. 767 */ 768 769 #if 0 /* Fool kernel-doc since it doesn't do macros yet */ 770 /* 771 * find_first_zero_bit - find the first zero bit in a memory region 772 * @addr: The address to start the search at 773 * @size: The maximum size to search 774 * 775 * Returns the bit-number of the first zero bit, not the number of the byte 776 * containing a bit. 777 */ 778 static int find_first_zero_bit (void *addr, unsigned size); 779 #endif 780 781 #define find_first_zero_bit(addr, size) \ 782 find_next_zero_bit((addr), (size), 0) 783 784 #endif /* (__MIPSEB__) */ 785 786 /* Now for the ext2 filesystem bit operations and helper routines. */ 787 788 #ifdef __MIPSEB__ 789 static __inline__ int ext2_set_bit(int nr, void * addr) 790 { 791 int mask, retval, flags; 792 unsigned char *ADDR = (unsigned char *) addr; 793 794 ADDR += nr >> 3; 795 mask = 1 << (nr & 0x07); 796 save_and_cli(flags); 797 retval = (mask & *ADDR) != 0; 798 *ADDR |= mask; 799 restore_flags(flags); 800 return retval; 801 } 802 803 static __inline__ int ext2_clear_bit(int nr, void * addr) 804 { 805 int mask, retval, flags; 806 unsigned char *ADDR = (unsigned char *) addr; 807 808 ADDR += nr >> 3; 809 mask = 1 << (nr & 0x07); 810 save_and_cli(flags); 811 retval = (mask & *ADDR) != 0; 812 *ADDR &= ~mask; 813 restore_flags(flags); 814 return retval; 815 } 816 817 static __inline__ int ext2_test_bit(int nr, const void * addr) 818 { 819 int mask; 820 const unsigned char *ADDR = (const unsigned char *) addr; 821 822 ADDR += nr >> 3; 823 mask = 1 << (nr & 0x07); 824 return ((mask & *ADDR) != 0); 825 } 826 827 #define ext2_find_first_zero_bit(addr, size) \ 828 ext2_find_next_zero_bit((addr), (size), 0) 829 830 static __inline__ unsigned long ext2_find_next_zero_bit(void *addr, unsigned long size, unsigned long offset) 831 { 832 unsigned long *p = ((unsigned long *) addr) + (offset >> 5); 833 unsigned long result = offset & ~31UL; 834 unsigned long tmp; 835 836 if (offset >= size) 837 return size; 838 size -= result; 839 offset &= 31UL; 840 if(offset) { 841 /* We hold the little endian value in tmp, but then the 842 * shift is illegal. So we could keep a big endian value 843 * in tmp, like this: 844 * 845 * tmp = __swab32(*(p++)); 846 * tmp |= ~0UL >> (32-offset); 847 * 848 * but this would decrease preformance, so we change the 849 * shift: 850 */ 851 tmp = *(p++); 852 tmp |= __swab32(~0UL >> (32-offset)); 853 if(size < 32) 854 goto found_first; 855 if(~tmp) 856 goto found_middle; 857 size -= 32; 858 result += 32; 859 } 860 while(size & ~31UL) { 861 if(~(tmp = *(p++))) 862 goto found_middle; 863 result += 32; 864 size -= 32; 865 } 866 if(!size) 867 return result; 868 tmp = *p; 869 870 found_first: 871 /* tmp is little endian, so we would have to swab the shift, 872 * see above. But then we have to swab tmp below for ffz, so 873 * we might as well do this here. 874 */ 875 return result + ffz(__swab32(tmp) | (~0UL << size)); 876 found_middle: 877 return result + ffz(__swab32(tmp)); 878 } 879 #else /* !(__MIPSEB__) */ 880 881 /* Native ext2 byte ordering, just collapse using defines. */ 882 #define ext2_set_bit(nr, addr) test_and_set_bit((nr), (addr)) 883 #define ext2_clear_bit(nr, addr) test_and_clear_bit((nr), (addr)) 884 #define ext2_test_bit(nr, addr) test_bit((nr), (addr)) 885 #define ext2_find_first_zero_bit(addr, size) find_first_zero_bit((addr), (size)) 886 #define ext2_find_next_zero_bit(addr, size, offset) \ 887 find_next_zero_bit((addr), (size), (offset)) 888 889 #endif /* !(__MIPSEB__) */ 890 891 /* 892 * Bitmap functions for the minix filesystem. 893 * FIXME: These assume that Minix uses the native byte/bitorder. 894 * This limits the Minix filesystem's value for data exchange very much. 895 */ 896 #define minix_test_and_set_bit(nr,addr) test_and_set_bit(nr,addr) 897 #define minix_set_bit(nr,addr) set_bit(nr,addr) 898 #define minix_test_and_clear_bit(nr,addr) test_and_clear_bit(nr,addr) 899 #define minix_test_bit(nr,addr) test_bit(nr,addr) 900 #define minix_find_first_zero_bit(addr,size) find_first_zero_bit(addr,size) 901 902 #endif /* _ASM_BITOPS_H */ 903