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
14 struct 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 */
21 static 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
29 static 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
37 static 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
44 static 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 */
54 struct 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 */
60 static 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
71 static 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 */
77 static 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
91 static 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 */
97 static inline unsigned long zero_bytemask(unsigned long mask)
98 {
99 return (1UL << mask) - 1;
100 }
101
102 #else /* 32-bit case */
103
104 struct 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 */
119 static 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
127 static inline unsigned long create_zero_mask(unsigned long bits)
128 {
129 bits = (bits - 1) & ~bits;
130 return bits >> 7;
131 }
132
133 static 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 */
139 static 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
146 static 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
167 static 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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