34 lines
856 B
C
34 lines
856 B
C
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/* ===-- clzti2.c - Implement __clzti2 -------------------------------------===
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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 __clzti2 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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#if __x86_64
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/* Returns: the number of leading 0-bits */
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/* Precondition: a != 0 */
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si_int
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__clzti2(ti_int a)
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{
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twords x;
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x.all = a;
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const di_int f = -(x.s.high == 0);
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return __builtin_clzll((x.s.high & ~f) | (x.s.low & f)) +
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((si_int)f & ((si_int)(sizeof(di_int) * CHAR_BIT)));
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}
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#endif /* __x86_64 */
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