| 1 | /* ===-- ffsti2.c - Implement __ffsti2 -------------------------------------=== |
| 2 | * |
| 3 | * The LLVM Compiler Infrastructure |
| 4 | * |
| 5 | * This file is dual licensed under the MIT and the University of Illinois Open |
| 6 | * Source Licenses. See LICENSE.TXT for details. |
| 7 | * |
| 8 | * ===----------------------------------------------------------------------=== |
| 9 | * |
| 10 | * This file implements __ffsti2 for the compiler_rt library. |
| 11 | * |
| 12 | * ===----------------------------------------------------------------------=== |
| 13 | */ |
| 14 | |
| 15 | #include "int_lib.h" |
| 16 | |
| 17 | #ifdef CRT_HAS_128BIT |
| 18 | |
| 19 | /* Returns: the index of the least significant 1-bit in a, or |
| 20 | * the value zero if a is zero. The least significant bit is index one. |
| 21 | */ |
| 22 | |
| 23 | COMPILER_RT_ABI si_int |
| 24 | __ffsti2(ti_int a) |
| 25 | { |
| 26 | twords x; |
| 27 | x.all = a; |
| 28 | if (x.s.low == 0) |
| 29 | { |
| 30 | if (x.s.high == 0) |
| 31 | return 0; |
| 32 | return __builtin_ctzll(x.s.high) + (1 + sizeof(di_int) * CHAR_BIT); |
| 33 | } |
| 34 | return __builtin_ctzll(x.s.low) + 1; |
| 35 | } |
| 36 | |
| 37 | #endif /* CRT_HAS_128BIT */ |
| 38 | |