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Line 14... | Line 14... | ||
14 | 14 | ||
15 | #include |
15 | #include |
Line 16... | Line 16... | ||
16 | #include |
16 | #include |
17 | - | ||
18 | /* |
- | |
19 | * deal with unrepresentable constant logarithms |
- | |
20 | */ |
- | |
21 | extern __attribute__((const, noreturn)) |
- | |
22 | int ____ilog2_NaN(void); |
- | |
23 | 17 | ||
24 | /* |
18 | /* |
25 | * non-constant log of base 2 calculators |
19 | * non-constant log of base 2 calculators |
26 | * - the arch may override these in asm/bitops.h if they can be implemented |
20 | * - the arch may override these in asm/bitops.h if they can be implemented |
27 | * more efficiently than using fls() and fls64() |
21 | * more efficiently than using fls() and fls64() |
Line 83... | Line 77... | ||
83 | * selects the appropriately-sized optimised version depending on sizeof(n) |
77 | * selects the appropriately-sized optimised version depending on sizeof(n) |
84 | */ |
78 | */ |
85 | #define ilog2(n) \ |
79 | #define ilog2(n) \ |
86 | ( \ |
80 | ( \ |
87 | __builtin_constant_p(n) ? ( \ |
81 | __builtin_constant_p(n) ? ( \ |
88 | (n) < 1 ? ____ilog2_NaN() : \ |
82 | (n) < 2 ? 0 : \ |
89 | (n) & (1ULL << 63) ? 63 : \ |
83 | (n) & (1ULL << 63) ? 63 : \ |
90 | (n) & (1ULL << 62) ? 62 : \ |
84 | (n) & (1ULL << 62) ? 62 : \ |
91 | (n) & (1ULL << 61) ? 61 : \ |
85 | (n) & (1ULL << 61) ? 61 : \ |
92 | (n) & (1ULL << 60) ? 60 : \ |
86 | (n) & (1ULL << 60) ? 60 : \ |
93 | (n) & (1ULL << 59) ? 59 : \ |
87 | (n) & (1ULL << 59) ? 59 : \ |
Line 146... | Line 140... | ||
146 | (n) & (1ULL << 6) ? 6 : \ |
140 | (n) & (1ULL << 6) ? 6 : \ |
147 | (n) & (1ULL << 5) ? 5 : \ |
141 | (n) & (1ULL << 5) ? 5 : \ |
148 | (n) & (1ULL << 4) ? 4 : \ |
142 | (n) & (1ULL << 4) ? 4 : \ |
149 | (n) & (1ULL << 3) ? 3 : \ |
143 | (n) & (1ULL << 3) ? 3 : \ |
150 | (n) & (1ULL << 2) ? 2 : \ |
144 | (n) & (1ULL << 2) ? 2 : \ |
151 | (n) & (1ULL << 1) ? 1 : \ |
- | |
152 | (n) & (1ULL << 0) ? 0 : \ |
- | |
153 | ____ilog2_NaN() \ |
- | |
154 | ) : \ |
145 | 1 ) : \ |
155 | (sizeof(n) <= 4) ? \ |
146 | (sizeof(n) <= 4) ? \ |
156 | __ilog2_u32(n) : \ |
147 | __ilog2_u32(n) : \ |
157 | __ilog2_u64(n) \ |
148 | __ilog2_u64(n) \ |
158 | ) |
149 | ) |
Line 201... | Line 192... | ||
201 | * ob2(4) = 2 |
192 | * ob2(4) = 2 |
202 | * ob2(5) = 3 |
193 | * ob2(5) = 3 |
203 | * ... and so on. |
194 | * ... and so on. |
204 | */ |
195 | */ |
Line -... | Line 196... | ||
- | 196 | ||
205 | 197 | static inline __attribute_const__ |
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- | 198 | int __order_base_2(unsigned long n) |
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- | 199 | { |
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- | 200 | return n > 1 ? ilog2(n - 1) + 1 : 0; |
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Line -... | Line 201... | ||
- | 201 | } |
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- | 202 | ||
- | 203 | #define order_base_2(n) \ |
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- | 204 | ( \ |
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- | 205 | __builtin_constant_p(n) ? ( \ |
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- | 206 | ((n) == 0 || (n) == 1) ? 0 : \ |
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- | 207 | ilog2((n) - 1) + 1) : \ |
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206 | #define order_base_2(n) ilog2(roundup_pow_of_two(n)) |
208 | __order_base_2(n) \ |