1*7c3d14c8STreehugger Robot /* ===-- ffsdi2.c - Implement __ffsdi2 -------------------------------------=== 2*7c3d14c8STreehugger Robot * 3*7c3d14c8STreehugger Robot * The LLVM Compiler Infrastructure 4*7c3d14c8STreehugger Robot * 5*7c3d14c8STreehugger Robot * This file is dual licensed under the MIT and the University of Illinois Open 6*7c3d14c8STreehugger Robot * Source Licenses. See LICENSE.TXT for details. 7*7c3d14c8STreehugger Robot * 8*7c3d14c8STreehugger Robot * ===----------------------------------------------------------------------=== 9*7c3d14c8STreehugger Robot * 10*7c3d14c8STreehugger Robot * This file implements __ffsdi2 for the compiler_rt library. 11*7c3d14c8STreehugger Robot * 12*7c3d14c8STreehugger Robot * ===----------------------------------------------------------------------=== 13*7c3d14c8STreehugger Robot */ 14*7c3d14c8STreehugger Robot 15*7c3d14c8STreehugger Robot #include "int_lib.h" 16*7c3d14c8STreehugger Robot 17*7c3d14c8STreehugger Robot /* Returns: the index of the least significant 1-bit in a, or 18*7c3d14c8STreehugger Robot * the value zero if a is zero. The least significant bit is index one. 19*7c3d14c8STreehugger Robot */ 20*7c3d14c8STreehugger Robot 21*7c3d14c8STreehugger Robot COMPILER_RT_ABI si_int __ffsdi2(di_int a)22*7c3d14c8STreehugger Robot__ffsdi2(di_int a) 23*7c3d14c8STreehugger Robot { 24*7c3d14c8STreehugger Robot dwords x; 25*7c3d14c8STreehugger Robot x.all = a; 26*7c3d14c8STreehugger Robot if (x.s.low == 0) 27*7c3d14c8STreehugger Robot { 28*7c3d14c8STreehugger Robot if (x.s.high == 0) 29*7c3d14c8STreehugger Robot return 0; 30*7c3d14c8STreehugger Robot return __builtin_ctz(x.s.high) + (1 + sizeof(si_int) * CHAR_BIT); 31*7c3d14c8STreehugger Robot } 32*7c3d14c8STreehugger Robot return __builtin_ctz(x.s.low) + 1; 33*7c3d14c8STreehugger Robot } 34