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1#ifndef _ASM_WORD_AT_A_TIME_H
2#define _ASM_WORD_AT_A_TIME_H
3
4/*
5 * Word-at-a-time interfaces for PowerPC.
6 */
7
8#include <linux/kernel.h>
9#include <asm/asm-compat.h>
10
11#ifdef __BIG_ENDIAN__
12
13struct word_at_a_time {
14 const unsigned long high_bits, low_bits;
15};
16
17#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0xfe) + 1, REPEAT_BYTE(0x7f) }
18
19/* Bit set in the bytes that have a zero */
20static inline long prep_zero_mask(unsigned long val, unsigned long rhs, const struct word_at_a_time *c)
21{
22 unsigned long mask = (val & c->low_bits) + c->low_bits;
23 return ~(mask | rhs);
24}
25
26#define create_zero_mask(mask) (mask)
27
28static inline long find_zero(unsigned long mask)
29{
30 long leading_zero_bits;
31
32 asm (PPC_CNTLZL "%0,%1" : "=r" (leading_zero_bits) : "r" (mask));
33 return leading_zero_bits >> 3;
34}
35
36static inline bool has_zero(unsigned long val, unsigned long *data, const struct word_at_a_time *c)
37{
38 unsigned long rhs = val | c->low_bits;
39 *data = rhs;
40 return (val + c->high_bits) & ~rhs;
41}
42
43#else
44
45struct word_at_a_time {
46 const unsigned long one_bits, high_bits;
47};
48
49#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }
50
51#ifdef CONFIG_64BIT
52
53/* Alan Modra's little-endian strlen tail for 64-bit */
54#define create_zero_mask(mask) (mask)
55
56static inline unsigned long find_zero(unsigned long mask)
57{
58 unsigned long leading_zero_bits;
59 long trailing_zero_bit_mask;
60
61 asm ("addi %1,%2,-1\n\t"
62 "andc %1,%1,%2\n\t"
63 "popcntd %0,%1"
64 : "=r" (leading_zero_bits), "=&r" (trailing_zero_bit_mask)
65 : "r" (mask));
66 return leading_zero_bits >> 3;
67}
68
69#else /* 32-bit case */
70
71/*
72 * This is largely generic for little-endian machines, but the
73 * optimal byte mask counting is probably going to be something
74 * that is architecture-specific. If you have a reliably fast
75 * bit count instruction, that might be better than the multiply
76 * and shift, for example.
77 */
78
79/* Carl Chatfield / Jan Achrenius G+ version for 32-bit */
80static inline long count_masked_bytes(long mask)
81{
82 /* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */
83 long a = (0x0ff0001+mask) >> 23;
84 /* Fix the 1 for 00 case */
85 return a & mask;
86}
87
88static inline unsigned long create_zero_mask(unsigned long bits)
89{
90 bits = (bits - 1) & ~bits;
91 return bits >> 7;
92}
93
94static inline unsigned long find_zero(unsigned long mask)
95{
96 return count_masked_bytes(mask);
97}
98
99#endif
100
101/* Return nonzero if it has a zero */
102static inline unsigned long has_zero(unsigned long a, unsigned long *bits, const struct word_at_a_time *c)
103{
104 unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits;
105 *bits = mask;
106 return mask;
107}
108
109static inline unsigned long prep_zero_mask(unsigned long a, unsigned long bits, const struct word_at_a_time *c)
110{
111 return bits;
112}
113
114/* The mask we created is directly usable as a bytemask */
115#define zero_bytemask(mask) (mask)
116
117#endif
118
119#endif /* _ASM_WORD_AT_A_TIME_H */