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>
static inline unsigned long find_first_bit(const unsigned long *addr,
unsigned long size)
{
- return find_next_bit(addr, size, 0);
+ unsigned long result, tmp;
+
+ for (result = 0; result < size; result += BITS_PER_LONG) {
+ tmp = *addr++;
+ if (tmp) {
+ result += ctzl(tmp);
+ return result < size ? result : size;
+ }
+ }
+ /* Not found */
+ return size;
}
/**