diff options
Diffstat (limited to 'lib/ffsti2.c')
-rw-r--r-- | lib/ffsti2.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/lib/ffsti2.c b/lib/ffsti2.c new file mode 100644 index 000000000..194c2cbb4 --- /dev/null +++ b/lib/ffsti2.c @@ -0,0 +1,35 @@ +//===-- ffsti2.c - Implement __ffsti2 -------------------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements __ffsti2 for the compiler_rt library. +// +//===----------------------------------------------------------------------===// + +#if __x86_64 + +#include "int_lib.h" + +// Returns: the index of the least significant 1-bit in a, or +// the value zero if a is zero. The least significant bit is index one. + +si_int +__ffsti2(ti_int a) +{ + twords x; + x.all = a; + if (x.low == 0) + { + if (x.high == 0) + return 0; + return __builtin_ctzll(x.high) + (1 + sizeof(di_int) * CHAR_BIT); + } + return __builtin_ctzll(x.low) + 1; +} + +#endif |