177ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao/* ===-- ffsdi2.c - Implement __ffsdi2 -------------------------------------=== 277ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao * 377ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao * The LLVM Compiler Infrastructure 477ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao * 577ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao * This file is distributed under the University of Illinois Open Source 677ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao * License. See LICENSE.TXT for details. 777ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao * 877ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao * ===----------------------------------------------------------------------=== 977ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao * 1077ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao * This file implements __ffsdi2 for the compiler_rt library. 1177ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao * 1277ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao * ===----------------------------------------------------------------------=== 1377ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao */ 1477ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao 1577ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao#include "int_lib.h" 1677ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao 1777ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao/* Returns: the index of the least significant 1-bit in a, or 1877ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao * the value zero if a is zero. The least significant bit is index one. 1977ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao */ 2077ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao 2177ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liaosi_int 2277ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao__ffsdi2(di_int a) 2377ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao{ 2477ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao dwords x; 2577ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao x.all = a; 2677ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao if (x.s.low == 0) 2777ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao { 2877ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao if (x.s.high == 0) 2977ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao return 0; 3077ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao return __builtin_ctz(x.s.high) + (1 + sizeof(si_int) * CHAR_BIT); 3177ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao } 3277ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao return __builtin_ctz(x.s.low) + 1; 3377ed6142daed1e068fbda64405d0de9845e40e1Shih-wei Liao} 34