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 #if __x86_64 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 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 /* __x86_64 */ 38
