bitops: provide an inline implementation of find_first_bit
find_first_bit has started to be used heavily in TCG code. The current implementation based on find_next_bit is not optimal and can't be optimized be the compiler if the bit array has a fixed size, which is the case most of the time. This new implementation does not use find_next_bit and is yet small enough to be inlined. Cc: Corentin Chary <corentin.chary@gmail.com> Reviewed-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
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@ -157,7 +157,17 @@ unsigned long find_next_zero_bit(const unsigned long *addr,
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static inline unsigned long find_first_bit(const unsigned long *addr,
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unsigned long size)
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{
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return find_next_bit(addr, size, 0);
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unsigned long result, tmp;
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for (result = 0; result < size; result += BITS_PER_LONG) {
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tmp = *addr++;
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if (tmp) {
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result += ctzl(tmp);
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return result < size ? result : size;
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}
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}
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/* Not found */
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return size;
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}
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/**
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