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29650b2b MK |
1 | /* ffs -- Find the first bit set in the parameter |
2 | ||
aac04c15 | 3 | @deftypefn Supplemental int ffs (int @var{valu}) |
29650b2b | 4 | |
5bed56d9 | 5 | Find the first (least significant) bit set in @var{valu}. Bits are |
aac04c15 DD |
6 | numbered from right to left, starting with bit 1 (corresponding to the |
7 | value 1). If @var{valu} is zero, zero is returned. | |
29650b2b | 8 | |
aac04c15 | 9 | @end deftypefn |
29650b2b MK |
10 | |
11 | */ | |
12 | ||
13 | int | |
6da879de | 14 | ffs (register int valu) |
29650b2b MK |
15 | { |
16 | register int bit; | |
17 | ||
18 | if (valu == 0) | |
19 | return 0; | |
20 | ||
21 | for (bit = 1; !(valu & 1); bit++) | |
22 | valu >>= 1; | |
23 | ||
24 | return bit; | |
25 | } | |
26 |