1/* ===-- ctzdi2.c - Implement __ctzdi2 -------------------------------------=== 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 __ctzdi2 for the compiler_rt library. 11 * 12 * ===----------------------------------------------------------------------=== 13 */
| 1//===-- ctzdi2.c - Implement __ctzdi2 -------------------------------------===// 2// 3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4// See https://llvm.org/LICENSE.txt for license information. 5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6// 7//===----------------------------------------------------------------------===// 8// 9// This file implements __ctzdi2 for the compiler_rt library. 10// 11//===----------------------------------------------------------------------===//
|
14 15#include "int_lib.h" 16
| 12 13#include "int_lib.h" 14
|
17/* Returns: the number of trailing 0-bits */
| 15// Returns: the number of trailing 0-bits
|
18 19#if !defined(__clang__) && \
| 16 17#if !defined(__clang__) && \
|
20 ((defined(__sparc__) && defined(__arch64__)) || \ 21 defined(__mips64) || \
| 18 ((defined(__sparc__) && defined(__arch64__)) || defined(__mips64) || \
|
22 (defined(__riscv) && __SIZEOF_POINTER__ >= 8))
| 19 (defined(__riscv) && __SIZEOF_POINTER__ >= 8))
|
23/* On 64-bit architectures with neither a native clz instruction nor a native 24 * ctz instruction, gcc resolves __builtin_ctz to __ctzdi2 rather than 25 * __ctzsi2, leading to infinite recursion. */
| 20// On 64-bit architectures with neither a native clz instruction nor a native 21// ctz instruction, gcc resolves __builtin_ctz to __ctzdi2 rather than 22// __ctzsi2, leading to infinite recursion.
|
26#define __builtin_ctz(a) __ctzsi2(a) 27extern si_int __ctzsi2(si_int); 28#endif 29
| 23#define __builtin_ctz(a) __ctzsi2(a) 24extern si_int __ctzsi2(si_int); 25#endif 26
|
30/* Precondition: a != 0 */
| 27// Precondition: a != 0
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31
| 28
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32COMPILER_RT_ABI si_int 33__ctzdi2(di_int a) 34{ 35 dwords x; 36 x.all = a; 37 const si_int f = -(x.s.low == 0); 38 return __builtin_ctz((x.s.high & f) | (x.s.low & ~f)) + 39 (f & ((si_int)(sizeof(si_int) * CHAR_BIT)));
| 29COMPILER_RT_ABI si_int __ctzdi2(di_int a) { 30 dwords x; 31 x.all = a; 32 const si_int f = -(x.s.low == 0); 33 return __builtin_ctz((x.s.high & f) | (x.s.low & ~f)) + 34 (f & ((si_int)(sizeof(si_int) * CHAR_BIT)));
|
40}
| 35}
|