1*7c3d14c8STreehugger Robot /* ===-- clzdi2.c - Implement __clzdi2 -------------------------------------=== 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 __clzdi2 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 number of leading 0-bits */ 18*7c3d14c8STreehugger Robot 19*7c3d14c8STreehugger Robot /* Precondition: a != 0 */ 20*7c3d14c8STreehugger Robot 21*7c3d14c8STreehugger Robot COMPILER_RT_ABI si_int __clzdi2(di_int a)22*7c3d14c8STreehugger Robot__clzdi2(di_int a) 23*7c3d14c8STreehugger Robot { 24*7c3d14c8STreehugger Robot dwords x; 25*7c3d14c8STreehugger Robot x.all = a; 26*7c3d14c8STreehugger Robot const si_int f = -(x.s.high == 0); 27*7c3d14c8STreehugger Robot return __builtin_clz((x.s.high & ~f) | (x.s.low & f)) + 28*7c3d14c8STreehugger Robot (f & ((si_int)(sizeof(si_int) * CHAR_BIT))); 29*7c3d14c8STreehugger Robot } 30