| Sandrine Bailleux | 9c01930 | 2017-07-19 14:05:47 +0100 | [diff] [blame] | 1 | /* ===-- ctzdi2.c - Implement __ctzdi2 -------------------------------------=== |
| 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 __ctzdi2 for the compiler_rt library. |
| 11 | * |
| 12 | * ===----------------------------------------------------------------------=== |
| 13 | */ |
| 14 | |
| 15 | #include "int_lib.h" |
| 16 | |
| 17 | /* Returns: the number of trailing 0-bits */ |
| 18 | |
| 19 | /* Precondition: a != 0 */ |
| 20 | |
| 21 | COMPILER_RT_ABI si_int |
| 22 | __ctzdi2(di_int a) |
| 23 | { |
| 24 | dwords x; |
| 25 | x.all = a; |
| 26 | const si_int f = -(x.s.low == 0); |
| 27 | return __builtin_ctz((x.s.high & f) | (x.s.low & ~f)) + |
| 28 | (f & ((si_int)(sizeof(si_int) * CHAR_BIT))); |
| 29 | } |