xref: /openbmc/u-boot/arch/mips/include/asm/bitops.h (revision d5cc3f52)
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, const 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