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@@ -77,31 +77,7 @@ static inline unsigned long __ffs(unsigned long word)
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static inline int fls(int x)
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{
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- int r = 32;
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-
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- if (!x)
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- return 0;
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- if (!(x & 0xffff0000u)) {
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- x <<= 16;
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- r -= 16;
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- }
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- if (!(x & 0xff000000u)) {
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- x <<= 8;
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- r -= 8;
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- }
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- if (!(x & 0xf0000000u)) {
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- x <<= 4;
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- r -= 4;
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- }
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- if (!(x & 0xc0000000u)) {
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- x <<= 2;
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- r -= 2;
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- }
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- if (!(x & 0x80000000u)) {
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- x <<= 1;
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- r -= 1;
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- }
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- return r;
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+ return 32 - __builtin_clz(x);
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}
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/**
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@@ -126,9 +102,7 @@ static inline int fls64(uint64_t x)
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#elif BITS_PER_LONG == 64
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static inline int fls64(uint64_t x)
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{
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- if (x == 0)
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- return 0;
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- return __fls(x) + 1;
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+ return 64 - __builtin_clzll(x);
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}
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#else
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#error BITS_PER_LONG not 32 or 64
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