1/*===---- lzcntintrin.h - LZCNT intrinsics ---------------------------------===
2 *
3 * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 * See https://llvm.org/LICENSE.txt for license information.
5 * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 *
7 *===-----------------------------------------------------------------------===
8 */
9
10#if !defined __X86INTRIN_H && !defined __IMMINTRIN_H
11#error "Never use <lzcntintrin.h> directly; include <x86intrin.h> instead."
12#endif
13
14#ifndef __LZCNTINTRIN_H
15#define __LZCNTINTRIN_H
16
17/* Define the default attributes for the functions in this file.
18 Allow using the lzcnt intrinsics even for non-LZCNT targets. Since the LZCNT
19 intrinsics are mapped to llvm.ctlz.*, false, which can be lowered to BSR on
20 non-LZCNT targets with zero-value input handled correctly. */
21#if defined(__cplusplus) && (__cplusplus >= 201103L)
22#define __DEFAULT_FN_ATTRS \
23 __attribute__((__always_inline__, __nodebug__)) constexpr
24#else
25#define __DEFAULT_FN_ATTRS __attribute__((__always_inline__, __nodebug__))
26#endif
27
28#ifndef _MSC_VER
29/// Counts the number of leading zero bits in the operand.
30///
31/// \headerfile <x86intrin.h>
32///
33/// This intrinsic corresponds to the \c LZCNT instruction.
34///
35/// \param __X
36/// An unsigned 16-bit integer whose leading zeros are to be counted.
37/// \returns An unsigned 16-bit integer containing the number of leading zero
38/// bits in the operand.
39#define __lzcnt16(X) __builtin_ia32_lzcnt_u16((unsigned short)(X))
40#endif // _MSC_VER
41
42/// Counts the number of leading zero bits in the operand.
43///
44/// \headerfile <x86intrin.h>
45///
46/// This intrinsic corresponds to the \c LZCNT instruction.
47///
48/// \param __X
49/// An unsigned 32-bit integer whose leading zeros are to be counted.
50/// \returns An unsigned 32-bit integer containing the number of leading zero
51/// bits in the operand.
52/// \see _lzcnt_u32
53static __inline__ unsigned int __DEFAULT_FN_ATTRS
54__lzcnt32(unsigned int __X) {
55 return __builtin_ia32_lzcnt_u32(__X);
56}
57
58/// Counts the number of leading zero bits in the operand.
59///
60/// \headerfile <x86intrin.h>
61///
62/// This intrinsic corresponds to the \c LZCNT instruction.
63///
64/// \param __X
65/// An unsigned 32-bit integer whose leading zeros are to be counted.
66/// \returns An unsigned 32-bit integer containing the number of leading zero
67/// bits in the operand.
68/// \see __lzcnt32
69static __inline__ unsigned int __DEFAULT_FN_ATTRS
70_lzcnt_u32(unsigned int __X) {
71 return __builtin_ia32_lzcnt_u32(__X);
72}
73
74#ifdef __x86_64__
75#ifndef _MSC_VER
76/// Counts the number of leading zero bits in the operand.
77///
78/// \headerfile <x86intrin.h>
79///
80/// This intrinsic corresponds to the \c LZCNT instruction.
81///
82/// \param __X
83/// An unsigned 64-bit integer whose leading zeros are to be counted.
84/// \returns An unsigned 64-bit integer containing the number of leading zero
85/// bits in the operand.
86/// \see _lzcnt_u64
87#define __lzcnt64(X) __builtin_ia32_lzcnt_u64((unsigned long long)(X))
88#endif // _MSC_VER
89
90/// Counts the number of leading zero bits in the operand.
91///
92/// \headerfile <x86intrin.h>
93///
94/// This intrinsic corresponds to the \c LZCNT instruction.
95///
96/// \param __X
97/// An unsigned 64-bit integer whose leading zeros are to be counted.
98/// \returns An unsigned 64-bit integer containing the number of leading zero
99/// bits in the operand.
100/// \see __lzcnt64
101static __inline__ unsigned long long __DEFAULT_FN_ATTRS
102_lzcnt_u64(unsigned long long __X) {
103 return __builtin_ia32_lzcnt_u64(__X);
104}
105#endif
106
107#undef __DEFAULT_FN_ATTRS
108
109#endif /* __LZCNTINTRIN_H */