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lzcntintrin.h
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1 /*===---- lzcntintrin.h - LZCNT intrinsics ---------------------------------===
2  *
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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.
44 static __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.
60 static __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.
76 static __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.
93 static __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.
109 static __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 */
static __inline__ unsigned short __DEFAULT_FN_ATTRS __lzcnt16(unsigned short __X)
Counts the number of leading zero bits in the operand.
Definition: lzcntintrin.h:45
static __inline__ unsigned int __DEFAULT_FN_ATTRS _lzcnt_u32(unsigned int __X)
Counts the number of leading zero bits in the operand.
Definition: lzcntintrin.h:77
static __inline__ unsigned int __DEFAULT_FN_ATTRS __lzcnt32(unsigned int __X)
Counts the number of leading zero bits in the operand.
Definition: lzcntintrin.h:61
#define __DEFAULT_FN_ATTRS
Definition: lzcntintrin.h:32