diff options
Diffstat (limited to 'lib/builtins/ctzdi2.c')
| -rw-r--r-- | lib/builtins/ctzdi2.c | 51 |
1 files changed, 23 insertions, 28 deletions
diff --git a/lib/builtins/ctzdi2.c b/lib/builtins/ctzdi2.c index ef6d7fea1..9384aa605 100644 --- a/lib/builtins/ctzdi2.c +++ b/lib/builtins/ctzdi2.c @@ -1,40 +1,35 @@ -/* ===-- ctzdi2.c - Implement __ctzdi2 -------------------------------------=== - * - * The LLVM Compiler Infrastructure - * - * This file is dual licensed under the MIT and the University of Illinois Open - * Source Licenses. See LICENSE.TXT for details. - * - * ===----------------------------------------------------------------------=== - * - * This file implements __ctzdi2 for the compiler_rt library. - * - * ===----------------------------------------------------------------------=== - */ +//===-- ctzdi2.c - Implement __ctzdi2 -------------------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// This file implements __ctzdi2 for the compiler_rt library. +// +//===----------------------------------------------------------------------===// #include "int_lib.h" -/* Returns: the number of trailing 0-bits */ +// Returns: the number of trailing 0-bits #if !defined(__clang__) && \ - ((defined(__sparc__) && defined(__arch64__)) || \ - defined(__mips64) || \ + ((defined(__sparc__) && defined(__arch64__)) || defined(__mips64) || \ (defined(__riscv) && __SIZEOF_POINTER__ >= 8)) -/* On 64-bit architectures with neither a native clz instruction nor a native - * ctz instruction, gcc resolves __builtin_ctz to __ctzdi2 rather than - * __ctzsi2, leading to infinite recursion. */ +// On 64-bit architectures with neither a native clz instruction nor a native +// ctz instruction, gcc resolves __builtin_ctz to __ctzdi2 rather than +// __ctzsi2, leading to infinite recursion. #define __builtin_ctz(a) __ctzsi2(a) extern si_int __ctzsi2(si_int); #endif -/* Precondition: a != 0 */ +// Precondition: a != 0 -COMPILER_RT_ABI si_int -__ctzdi2(di_int a) -{ - dwords x; - x.all = a; - const si_int f = -(x.s.low == 0); - return __builtin_ctz((x.s.high & f) | (x.s.low & ~f)) + - (f & ((si_int)(sizeof(si_int) * CHAR_BIT))); +COMPILER_RT_ABI si_int __ctzdi2(di_int a) { + dwords x; + x.all = a; + const si_int f = -(x.s.low == 0); + return __builtin_ctz((x.s.high & f) | (x.s.low & ~f)) + + (f & ((si_int)(sizeof(si_int) * CHAR_BIT))); } |