diff options
| author | "Steven J. Hill" <sjhill@realitydiluted.com> | 2006-01-07 02:32:27 +0000 |
|---|---|---|
| committer | "Steven J. Hill" <sjhill@realitydiluted.com> | 2006-01-07 02:32:27 +0000 |
| commit | e523bd15353350c3480b8a1820a0944b0fa8212e (patch) | |
| tree | 60485116f9c62c306bb753f12f9d4eb79d16aa4e /libc/string/ffs.c | |
| parent | 3b3434516a3415d7e0f4e1d50c553876dcb337b2 (diff) | |
| download | uClibc-alpine-e523bd15353350c3480b8a1820a0944b0fa8212e.tar.bz2 uClibc-alpine-e523bd15353350c3480b8a1820a0944b0fa8212e.tar.xz | |
Big fricking merge from trunk.
Diffstat (limited to 'libc/string/ffs.c')
| -rw-r--r-- | libc/string/ffs.c | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/libc/string/ffs.c b/libc/string/ffs.c new file mode 100644 index 000000000..fc76e6c70 --- /dev/null +++ b/libc/string/ffs.c @@ -0,0 +1,54 @@ +/* + * Copyright (C) 2002 Manuel Novoa III + * Copyright (C) 2000-2005 Erik Andersen <andersen@uclibc.org> + * + * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball. + */ + +/* ffsl,ffsll */ + +#include "_string.h" + +int attribute_hidden __ffs(int i) +{ +#if 1 + /* inlined binary search method */ + char n = 1; +#if UINT_MAX == 0xffffU + /* nothing to do here -- just trying to avoiding possible problems */ +#elif UINT_MAX == 0xffffffffU + if (!(i & 0xffff)) { + n += 16; + i >>= 16; + } +#else +#error ffs needs rewriting! +#endif + + if (!(i & 0xff)) { + n += 8; + i >>= 8; + } + if (!(i & 0x0f)) { + n += 4; + i >>= 4; + } + if (!(i & 0x03)) { + n += 2; + i >>= 2; + } + return (i) ? (n + ((i+1) & 0x01)) : 0; + +#else + /* linear search -- slow, but small */ + int n; + + for (n = 0 ; i ; ++n) { + i >>= 1; + } + + return n; +#endif +} + +strong_alias(__ffs,ffs) |