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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_WORD_AT_A_TIME_H
3#define _ASM_WORD_AT_A_TIME_H
4
5#include <linux/bitops.h>
6#include <linux/wordpart.h>
7#include <asm/byteorder.h>
8
9#ifdef __BIG_ENDIAN
10
11struct word_at_a_time {
12 const unsigned long high_bits, low_bits;
13};
14
15#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0xfe) + 1, REPEAT_BYTE(0x7f) }
16
17/* Bit set in the bytes that have a zero */
18static inline long prep_zero_mask(unsigned long val, unsigned long rhs, const struct word_at_a_time *c)
19{
20 unsigned long mask = (val & c->low_bits) + c->low_bits;
21 return ~(mask | rhs);
22}
23
24#define create_zero_mask(mask) (mask)
25
26static inline long find_zero(unsigned long mask)
27{
28 long byte = 0;
29#ifdef CONFIG_64BIT
30 if (mask >> 32)
31 mask >>= 32;
32 else
33 byte = 4;
34#endif
35 if (mask >> 16)
36 mask >>= 16;
37 else
38 byte += 2;
39 return (mask >> 8) ? byte : byte + 1;
40}
41
42static inline unsigned long has_zero(unsigned long val, unsigned long *data, const struct word_at_a_time *c)
43{
44 unsigned long rhs = val | c->low_bits;
45 *data = rhs;
46 return (val + c->high_bits) & ~rhs;
47}
48
49#ifndef zero_bytemask
50#define zero_bytemask(mask) (~1ul << __fls(mask))
51#endif
52
53#else
54
55/*
56 * The optimal byte mask counting is probably going to be something
57 * that is architecture-specific. If you have a reliably fast
58 * bit count instruction, that might be better than the multiply
59 * and shift, for example.
60 */
61struct word_at_a_time {
62 const unsigned long one_bits, high_bits;
63};
64
65#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }
66
67#ifdef CONFIG_64BIT
68
69/*
70 * Jan Achrenius on G+: microoptimized version of
71 * the simpler "(mask & ONEBYTES) * ONEBYTES >> 56"
72 * that works for the bytemasks without having to
73 * mask them first.
74 */
75static inline long count_masked_bytes(unsigned long mask)
76{
77 return mask*0x0001020304050608ul >> 56;
78}
79
80#else /* 32-bit case */
81
82/* Carl Chatfield / Jan Achrenius G+ version for 32-bit */
83static inline long count_masked_bytes(long mask)
84{
85 /* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */
86 long a = (0x0ff0001+mask) >> 23;
87 /* Fix the 1 for 00 case */
88 return a & mask;
89}
90
91#endif
92
93/* Return nonzero if it has a zero */
94static inline unsigned long has_zero(unsigned long a, unsigned long *bits, const struct word_at_a_time *c)
95{
96 unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits;
97 *bits = mask;
98 return mask;
99}
100
101static inline unsigned long prep_zero_mask(unsigned long a, unsigned long bits, const struct word_at_a_time *c)
102{
103 return bits;
104}
105
106static inline unsigned long create_zero_mask(unsigned long bits)
107{
108 bits = (bits - 1) & ~bits;
109 return bits >> 7;
110}
111
112/* The mask we created is directly usable as a bytemask */
113#define zero_bytemask(mask) (mask)
114
115static inline unsigned long find_zero(unsigned long mask)
116{
117 return count_masked_bytes(mask);
118}
119
120#endif /* __BIG_ENDIAN */
121
122#endif /* _ASM_WORD_AT_A_TIME_H */
1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_WORD_AT_A_TIME_H
3#define _ASM_WORD_AT_A_TIME_H
4
5#include <linux/kernel.h>
6#include <asm/byteorder.h>
7
8#ifdef __BIG_ENDIAN
9
10struct word_at_a_time {
11 const unsigned long high_bits, low_bits;
12};
13
14#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0xfe) + 1, REPEAT_BYTE(0x7f) }
15
16/* Bit set in the bytes that have a zero */
17static inline long prep_zero_mask(unsigned long val, unsigned long rhs, const struct word_at_a_time *c)
18{
19 unsigned long mask = (val & c->low_bits) + c->low_bits;
20 return ~(mask | rhs);
21}
22
23#define create_zero_mask(mask) (mask)
24
25static inline long find_zero(unsigned long mask)
26{
27 long byte = 0;
28#ifdef CONFIG_64BIT
29 if (mask >> 32)
30 mask >>= 32;
31 else
32 byte = 4;
33#endif
34 if (mask >> 16)
35 mask >>= 16;
36 else
37 byte += 2;
38 return (mask >> 8) ? byte : byte + 1;
39}
40
41static inline bool has_zero(unsigned long val, unsigned long *data, const struct word_at_a_time *c)
42{
43 unsigned long rhs = val | c->low_bits;
44 *data = rhs;
45 return (val + c->high_bits) & ~rhs;
46}
47
48#ifndef zero_bytemask
49#define zero_bytemask(mask) (~1ul << __fls(mask))
50#endif
51
52#else
53
54/*
55 * The optimal byte mask counting is probably going to be something
56 * that is architecture-specific. If you have a reliably fast
57 * bit count instruction, that might be better than the multiply
58 * and shift, for example.
59 */
60struct word_at_a_time {
61 const unsigned long one_bits, high_bits;
62};
63
64#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }
65
66#ifdef CONFIG_64BIT
67
68/*
69 * Jan Achrenius on G+: microoptimized version of
70 * the simpler "(mask & ONEBYTES) * ONEBYTES >> 56"
71 * that works for the bytemasks without having to
72 * mask them first.
73 */
74static inline long count_masked_bytes(unsigned long mask)
75{
76 return mask*0x0001020304050608ul >> 56;
77}
78
79#else /* 32-bit case */
80
81/* Carl Chatfield / Jan Achrenius G+ version for 32-bit */
82static inline long count_masked_bytes(long mask)
83{
84 /* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */
85 long a = (0x0ff0001+mask) >> 23;
86 /* Fix the 1 for 00 case */
87 return a & mask;
88}
89
90#endif
91
92/* Return nonzero if it has a zero */
93static inline unsigned long has_zero(unsigned long a, unsigned long *bits, const struct word_at_a_time *c)
94{
95 unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits;
96 *bits = mask;
97 return mask;
98}
99
100static inline unsigned long prep_zero_mask(unsigned long a, unsigned long bits, const struct word_at_a_time *c)
101{
102 return bits;
103}
104
105static inline unsigned long create_zero_mask(unsigned long bits)
106{
107 bits = (bits - 1) & ~bits;
108 return bits >> 7;
109}
110
111/* The mask we created is directly usable as a bytemask */
112#define zero_bytemask(mask) (mask)
113
114static inline unsigned long find_zero(unsigned long mask)
115{
116 return count_masked_bytes(mask);
117}
118
119#endif /* __BIG_ENDIAN */
120
121#endif /* _ASM_WORD_AT_A_TIME_H */