clzdi2.c revision 303975
1159952Sobrien/* ===-- clzdi2.c - Implement __clzdi2 -------------------------------------=== 2159952Sobrien * 3159952Sobrien * The LLVM Compiler Infrastructure 4159952Sobrien * 5159952Sobrien * This file is dual licensed under the MIT and the University of Illinois Open 6159952Sobrien * Source Licenses. See LICENSE.TXT for details. 7159952Sobrien * 8159952Sobrien * ===----------------------------------------------------------------------=== 9159952Sobrien * 10159952Sobrien * This file implements __clzdi2 for the compiler_rt library. 11159952Sobrien * 12159952Sobrien * ===----------------------------------------------------------------------=== 13159952Sobrien */ 14159952Sobrien 15159952Sobrien#include "int_lib.h" 16159952Sobrien 17159967Sobrien/* Returns: the number of leading 0-bits */ 18159967Sobrien 19159952Sobrien/* Precondition: a != 0 */ 20159952Sobrien 21159952SobrienCOMPILER_RT_ABI si_int 22159967Sobrien__clzdi2(di_int a) 23159952Sobrien{ 24159952Sobrien dwords x; 25159952Sobrien x.all = a; 26159952Sobrien const si_int f = -(x.s.high == 0); 27170589Syongari return __builtin_clz((x.s.high & ~f) | (x.s.low & f)) + 28159967Sobrien (f & ((si_int)(sizeof(si_int) * CHAR_BIT))); 29159952Sobrien} 30159952Sobrien