forked from OSchip/llvm-project
36 lines
1.1 KiB
C
36 lines
1.1 KiB
C
/* ===-- ctzdi2.c - Implement __ctzdi2 -------------------------------------===
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*
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* The LLVM Compiler Infrastructure
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*
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* This file is dual licensed under the MIT and the University of Illinois Open
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* Source Licenses. See LICENSE.TXT for details.
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*
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* ===----------------------------------------------------------------------===
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*
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* This file implements __ctzdi2 for the compiler_rt library.
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*
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* ===----------------------------------------------------------------------===
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*/
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#include "int_lib.h"
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/* Returns: the number of trailing 0-bits */
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#if !defined(__clang__) && (defined(__sparc64__) || defined(__mips64) || defined(__riscv__))
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/* gcc resolves __builtin_ctz -> __ctzdi2 leading to infinite recursion */
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#define __builtin_ctz(a) __ctzsi2(a)
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extern si_int __ctzsi2(si_int);
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#endif
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/* Precondition: a != 0 */
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COMPILER_RT_ABI si_int
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__ctzdi2(di_int a)
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{
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dwords x;
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x.all = a;
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const si_int f = -(x.s.low == 0);
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return __builtin_ctz((x.s.high & f) | (x.s.low & ~f)) +
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(f & ((si_int)(sizeof(si_int) * CHAR_BIT)));
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}
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