xref: /openbsd-src/gnu/llvm/compiler-rt/lib/builtins/clzti2.c (revision 1f9cb04fc6f537ca6cf5a53c28927340cba218a2)
13cab2bb3Spatrick //===-- clzti2.c - Implement __clzti2 -------------------------------------===//
23cab2bb3Spatrick //
33cab2bb3Spatrick // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
43cab2bb3Spatrick // See https://llvm.org/LICENSE.txt for license information.
53cab2bb3Spatrick // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
63cab2bb3Spatrick //
73cab2bb3Spatrick //===----------------------------------------------------------------------===//
83cab2bb3Spatrick //
93cab2bb3Spatrick // This file implements __clzti2 for the compiler_rt library.
103cab2bb3Spatrick //
113cab2bb3Spatrick //===----------------------------------------------------------------------===//
123cab2bb3Spatrick 
133cab2bb3Spatrick #include "int_lib.h"
143cab2bb3Spatrick 
153cab2bb3Spatrick #ifdef CRT_HAS_128BIT
163cab2bb3Spatrick 
173cab2bb3Spatrick // Returns: the number of leading 0-bits
183cab2bb3Spatrick 
193cab2bb3Spatrick // Precondition: a != 0
203cab2bb3Spatrick 
__clzti2(ti_int a)21*1f9cb04fSpatrick COMPILER_RT_ABI int __clzti2(ti_int a) {
223cab2bb3Spatrick   twords x;
233cab2bb3Spatrick   x.all = a;
243cab2bb3Spatrick   const di_int f = -(x.s.high == 0);
253cab2bb3Spatrick   return __builtin_clzll((x.s.high & ~f) | (x.s.low & f)) +
263cab2bb3Spatrick          ((si_int)f & ((si_int)(sizeof(di_int) * CHAR_BIT)));
273cab2bb3Spatrick }
283cab2bb3Spatrick 
293cab2bb3Spatrick #endif // CRT_HAS_128BIT
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