lzcntintrin.h revision 314564 
1/*===---- lzcntintrin.h - LZCNT intrinsics ---------------------------------===
2 *
3 * Permission is hereby granted, free of charge, to any person obtaining a copy
4 * of this software and associated documentation files (the "Software"), to deal
5 * in the Software without restriction, including without limitation the rights
6 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
7 * copies of the Software, and to permit persons to whom the Software is
8 * furnished to do so, subject to the following conditions:
9 *
10 * The above copyright notice and this permission notice shall be included in
11 * all copies or substantial portions of the Software.
12 *
13 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
14 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
15 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
16 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
17 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
18 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
19 * THE SOFTWARE.
20 *
21 *===-----------------------------------------------------------------------===
22 */
23
24#if !defined __X86INTRIN_H && !defined __IMMINTRIN_H
25#error "Never use <lzcntintrin.h> directly; include <x86intrin.h> instead."
26#endif
27
28#ifndef __LZCNTINTRIN_H
29#define __LZCNTINTRIN_H
30
31/* Define the default attributes for the functions in this file. */
32#define __DEFAULT_FN_ATTRS __attribute__((__always_inline__, __nodebug__, __target__("lzcnt")))
33
34/// \brief Counts the number of leading zero bits in the operand.
35///
36/// \headerfile <x86intrin.h>
37///
38/// This intrinsic corresponds to the \c LZCNT instruction.
39///
40/// \param __X
41///    An unsigned 16-bit integer whose leading zeros are to be counted.
42/// \returns An unsigned 16-bit integer containing the number of leading zero
43///    bits in the operand.
44static __inline__ unsigned short __DEFAULT_FN_ATTRS
45__lzcnt16(unsigned short __X)
46{
47  return __X ? __builtin_clzs(__X) : 16;
48}
49
50/// \brief Counts the number of leading zero bits in the operand.
51///
52/// \headerfile <x86intrin.h>
53///
54/// This intrinsic corresponds to the \c LZCNT instruction.
55///
56/// \param __X
57///    An unsigned 32-bit integer whose leading zeros are to be counted.
58/// \returns An unsigned 32-bit integer containing the number of leading zero
59///    bits in the operand.
60static __inline__ unsigned int __DEFAULT_FN_ATTRS
61__lzcnt32(unsigned int __X)
62{
63  return __X ? __builtin_clz(__X) : 32;
64}
65
66/// \brief Counts the number of leading zero bits in the operand.
67///
68/// \headerfile <x86intrin.h>
69///
70/// This intrinsic corresponds to the \c LZCNT instruction.
71///
72/// \param __X
73///    An unsigned 32-bit integer whose leading zeros are to be counted.
74/// \returns An unsigned 32-bit integer containing the number of leading zero
75///    bits in the operand.
76static __inline__ unsigned int __DEFAULT_FN_ATTRS
77_lzcnt_u32(unsigned int __X)
78{
79  return __X ? __builtin_clz(__X) : 32;
80}
81
82#ifdef __x86_64__
83/// \brief Counts the number of leading zero bits in the operand.
84///
85/// \headerfile <x86intrin.h>
86///
87/// This intrinsic corresponds to the \c LZCNT instruction.
88///
89/// \param __X
90///    An unsigned 64-bit integer whose leading zeros are to be counted.
91/// \returns An unsigned 64-bit integer containing the number of leading zero
92///    bits in the operand.
93static __inline__ unsigned long long __DEFAULT_FN_ATTRS
94__lzcnt64(unsigned long long __X)
95{
96  return __X ? __builtin_clzll(__X) : 64;
97}
98
99/// \brief Counts the number of leading zero bits in the operand.
100///
101/// \headerfile <x86intrin.h>
102///
103/// This intrinsic corresponds to the \c LZCNT instruction.
104///
105/// \param __X
106///    An unsigned 64-bit integer whose leading zeros are to be counted.
107/// \returns An unsigned 64-bit integer containing the number of leading zero
108///    bits in the operand.
109static __inline__ unsigned long long __DEFAULT_FN_ATTRS
110_lzcnt_u64(unsigned long long __X)
111{
112  return __X ? __builtin_clzll(__X) : 64;
113}
114#endif
115
116#undef __DEFAULT_FN_ATTRS
117
118#endif /* __LZCNTINTRIN_H */
119