xref: /freebsd-src/contrib/llvm-project/compiler-rt/lib/builtins/clzti2.c (revision e25152834cdf3b353892835a4f3b157e066a8ed4)
10b57cec5SDimitry Andric //===-- clzti2.c - Implement __clzti2 -------------------------------------===//
20b57cec5SDimitry Andric //
30b57cec5SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
40b57cec5SDimitry Andric // See https://llvm.org/LICENSE.txt for license information.
50b57cec5SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
60b57cec5SDimitry Andric //
70b57cec5SDimitry Andric //===----------------------------------------------------------------------===//
80b57cec5SDimitry Andric //
90b57cec5SDimitry Andric // This file implements __clzti2 for the compiler_rt library.
100b57cec5SDimitry Andric //
110b57cec5SDimitry Andric //===----------------------------------------------------------------------===//
120b57cec5SDimitry Andric 
130b57cec5SDimitry Andric #include "int_lib.h"
140b57cec5SDimitry Andric 
150b57cec5SDimitry Andric #ifdef CRT_HAS_128BIT
160b57cec5SDimitry Andric 
170b57cec5SDimitry Andric // Returns: the number of leading 0-bits
180b57cec5SDimitry Andric 
190b57cec5SDimitry Andric // Precondition: a != 0
200b57cec5SDimitry Andric 
__clzti2(ti_int a)21*5ffd83dbSDimitry Andric COMPILER_RT_ABI int __clzti2(ti_int a) {
220b57cec5SDimitry Andric   twords x;
230b57cec5SDimitry Andric   x.all = a;
240b57cec5SDimitry Andric   const di_int f = -(x.s.high == 0);
250b57cec5SDimitry Andric   return __builtin_clzll((x.s.high & ~f) | (x.s.low & f)) +
260b57cec5SDimitry Andric          ((si_int)f & ((si_int)(sizeof(di_int) * CHAR_BIT)));
270b57cec5SDimitry Andric }
280b57cec5SDimitry Andric 
290b57cec5SDimitry Andric #endif // CRT_HAS_128BIT
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