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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#include <linux/bitops.h>
8#include <linux/wordpart.h>
9#include <asm/asm-compat.h>
10#include <asm/extable.h>
11
12#ifdef __BIG_ENDIAN__
13
14struct word_at_a_time {
15 const unsigned long high_bits, low_bits;
16};
17
18#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0xfe) + 1, REPEAT_BYTE(0x7f) }
19
20/* Bit set in the bytes that have a zero */
21static inline long prep_zero_mask(unsigned long val, unsigned long rhs, const struct word_at_a_time *c)
22{
23 unsigned long mask = (val & c->low_bits) + c->low_bits;
24 return ~(mask | rhs);
25}
26
27#define create_zero_mask(mask) (mask)
28
29static inline long find_zero(unsigned long mask)
30{
31 long leading_zero_bits;
32
33 asm (PPC_CNTLZL "%0,%1" : "=r" (leading_zero_bits) : "r" (mask));
34 return leading_zero_bits >> 3;
35}
36
37static inline unsigned long has_zero(unsigned long val, unsigned long *data, const struct word_at_a_time *c)
38{
39 unsigned long rhs = val | c->low_bits;
40 *data = rhs;
41 return (val + c->high_bits) & ~rhs;
42}
43
44static inline unsigned long zero_bytemask(unsigned long mask)
45{
46 return ~1ul << __fls(mask);
47}
48
49#else
50
51#ifdef CONFIG_64BIT
52
53/* unused */
54struct word_at_a_time {
55};
56
57#define WORD_AT_A_TIME_CONSTANTS { }
58
59/* This will give us 0xff for a NULL char and 0x00 elsewhere */
60static inline unsigned long has_zero(unsigned long a, unsigned long *bits, const struct word_at_a_time *c)
61{
62 unsigned long ret;
63 unsigned long zero = 0;
64
65 asm("cmpb %0,%1,%2" : "=r" (ret) : "r" (a), "r" (zero));
66 *bits = ret;
67
68 return ret;
69}
70
71static inline unsigned long prep_zero_mask(unsigned long a, unsigned long bits, const struct word_at_a_time *c)
72{
73 return bits;
74}
75
76/* Alan Modra's little-endian strlen tail for 64-bit */
77static inline unsigned long create_zero_mask(unsigned long bits)
78{
79 unsigned long leading_zero_bits;
80 long trailing_zero_bit_mask;
81
82 asm("addi %1,%2,-1\n\t"
83 "andc %1,%1,%2\n\t"
84 "popcntd %0,%1"
85 : "=r" (leading_zero_bits), "=&r" (trailing_zero_bit_mask)
86 : "b" (bits));
87
88 return leading_zero_bits;
89}
90
91static inline unsigned long find_zero(unsigned long mask)
92{
93 return mask >> 3;
94}
95
96/* This assumes that we never ask for an all 1s bitmask */
97static inline unsigned long zero_bytemask(unsigned long mask)
98{
99 return (1UL << mask) - 1;
100}
101
102#else /* 32-bit case */
103
104struct word_at_a_time {
105 const unsigned long one_bits, high_bits;
106};
107
108#define WORD_AT_A_TIME_CONSTANTS { REPEAT_BYTE(0x01), REPEAT_BYTE(0x80) }
109
110/*
111 * This is largely generic for little-endian machines, but the
112 * optimal byte mask counting is probably going to be something
113 * that is architecture-specific. If you have a reliably fast
114 * bit count instruction, that might be better than the multiply
115 * and shift, for example.
116 */
117
118/* Carl Chatfield / Jan Achrenius G+ version for 32-bit */
119static inline long count_masked_bytes(long mask)
120{
121 /* (000000 0000ff 00ffff ffffff) -> ( 1 1 2 3 ) */
122 long a = (0x0ff0001+mask) >> 23;
123 /* Fix the 1 for 00 case */
124 return a & mask;
125}
126
127static inline unsigned long create_zero_mask(unsigned long bits)
128{
129 bits = (bits - 1) & ~bits;
130 return bits >> 7;
131}
132
133static inline unsigned long find_zero(unsigned long mask)
134{
135 return count_masked_bytes(mask);
136}
137
138/* Return nonzero if it has a zero */
139static inline unsigned long has_zero(unsigned long a, unsigned long *bits, const struct word_at_a_time *c)
140{
141 unsigned long mask = ((a - c->one_bits) & ~a) & c->high_bits;
142 *bits = mask;
143 return mask;
144}
145
146static inline unsigned long prep_zero_mask(unsigned long a, unsigned long bits, const struct word_at_a_time *c)
147{
148 return bits;
149}
150
151/* The mask we created is directly usable as a bytemask */
152#define zero_bytemask(mask) (mask)
153
154#endif /* CONFIG_64BIT */
155
156#endif /* __BIG_ENDIAN__ */
157
158/*
159 * We use load_unaligned_zero() in a selftest, which builds a userspace
160 * program. Some linker scripts seem to discard the .fixup section, so allow
161 * the test code to use a different section name.
162 */
163#ifndef FIXUP_SECTION
164#define FIXUP_SECTION ".fixup"
165#endif
166
167static inline unsigned long load_unaligned_zeropad(const void *addr)
168{
169 unsigned long ret, offset, tmp;
170
171 asm(
172 "1: " PPC_LL "%[ret], 0(%[addr])\n"
173 "2:\n"
174 ".section " FIXUP_SECTION ",\"ax\"\n"
175 "3: "
176#ifdef __powerpc64__
177 "clrrdi %[tmp], %[addr], 3\n\t"
178 "clrlsldi %[offset], %[addr], 61, 3\n\t"
179 "ld %[ret], 0(%[tmp])\n\t"
180#ifdef __BIG_ENDIAN__
181 "sld %[ret], %[ret], %[offset]\n\t"
182#else
183 "srd %[ret], %[ret], %[offset]\n\t"
184#endif
185#else
186 "clrrwi %[tmp], %[addr], 2\n\t"
187 "clrlslwi %[offset], %[addr], 30, 3\n\t"
188 "lwz %[ret], 0(%[tmp])\n\t"
189#ifdef __BIG_ENDIAN__
190 "slw %[ret], %[ret], %[offset]\n\t"
191#else
192 "srw %[ret], %[ret], %[offset]\n\t"
193#endif
194#endif
195 "b 2b\n"
196 ".previous\n"
197 EX_TABLE(1b, 3b)
198 : [tmp] "=&b" (tmp), [offset] "=&r" (offset), [ret] "=&r" (ret)
199 : [addr] "b" (addr), "m" (*(unsigned long *)addr));
200
201 return ret;
202}
203
204#undef FIXUP_SECTION
205
206#endif /* _ASM_WORD_AT_A_TIME_H */
207

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source code of linux/arch/powerpc/include/asm/word-at-a-time.h