xref: /kvm-unit-tests/lib/bitops.h (revision d5b60621b0e6863fd62e4657b7a2ec70bf7eee34)
1 #ifndef _BITOPS_H_
2 #define _BITOPS_H_
3 
4 /*
5  * Adapted from
6  *   include/linux/bitops.h
7  *
8  * Copyright (C) 2017, Red Hat Inc, Andrew Jones <drjones@redhat.com>
9  *
10  * This work is licensed under the terms of the GNU GPL, version 2.
11  */
12 
13 #define BITS_PER_LONG_LONG	64
14 #define BIT(nr)			(1UL << (nr))
15 #define BIT_ULL(nr)		(1ULL << (nr))
16 #define BIT_MASK(nr)		(1UL << ((nr) % BITS_PER_LONG))
17 #define BIT_WORD(nr)		((nr) / BITS_PER_LONG)
18 #define BIT_ULL_MASK(nr)	(1ULL << ((nr) % BITS_PER_LONG_LONG))
19 #define BIT_ULL_WORD(nr)	((nr) / BITS_PER_LONG_LONG)
20 #define BITS_PER_BYTE		8
21 #define BITS_TO_LONGS(nr)	DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
22 
23 #include <asm/bitops.h>
24 
25 /*
26  * Create a contiguous bitmask starting at bit position @l and ending at
27  * position @h. For example
28  * GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
29  */
30 #define GENMASK(h, l) \
31 	(((~0UL) << (l)) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
32 
33 #define GENMASK_ULL(h, l) \
34 	(((~0ULL) << (l)) & (~0ULL >> (BITS_PER_LONG_LONG - 1 - (h))))
35 
36 #ifndef HAVE_BUILTIN_FLS
37 static inline unsigned long fls(unsigned long word)
38 {
39 	int num = BITS_PER_LONG - 1;
40 
41 #if BITS_PER_LONG == 64
42 	if (!(word & (~0ul << 32))) {
43 		num -= 32;
44 		word <<= 32;
45 	}
46 #endif
47 	if (!(word & (~0ul << (BITS_PER_LONG-16)))) {
48 		num -= 16;
49 		word <<= 16;
50 	}
51 	if (!(word & (~0ul << (BITS_PER_LONG-8)))) {
52 		num -= 8;
53 		word <<= 8;
54 	}
55 	if (!(word & (~0ul << (BITS_PER_LONG-4)))) {
56 		num -= 4;
57 		word <<= 4;
58 	}
59 	if (!(word & (~0ul << (BITS_PER_LONG-2)))) {
60 		num -= 2;
61 		word <<= 2;
62 	}
63 	if (!(word & (~0ul << (BITS_PER_LONG-1))))
64 		num -= 1;
65 	return num;
66 }
67 #else
68 static inline unsigned long fls(unsigned long word)
69 {
70 	return BITS_PER_LONG - __builtin_clzl(word) - 1;
71 }
72 #endif
73 
74 #endif
75