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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 /// 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 /// 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 /// \see _lzcnt_u32
61 static __inline__ unsigned int __DEFAULT_FN_ATTRS
62 __lzcnt32(unsigned int __X)
63 {
64  return __X ? __builtin_clz(__X) : 32;
65 }
66 
67 /// Counts the number of leading zero bits in the operand.
68 ///
69 /// \headerfile <x86intrin.h>
70 ///
71 /// This intrinsic corresponds to the \c LZCNT instruction.
72 ///
73 /// \param __X
74 /// An unsigned 32-bit integer whose leading zeros are to be counted.
75 /// \returns An unsigned 32-bit integer containing the number of leading zero
76 /// bits in the operand.
77 /// \see __lzcnt32
78 static __inline__ unsigned int __DEFAULT_FN_ATTRS
79 _lzcnt_u32(unsigned int __X)
80 {
81  return __X ? __builtin_clz(__X) : 32;
82 }
83 
84 #ifdef __x86_64__
85 /// Counts the number of leading zero bits in the operand.
86 ///
87 /// \headerfile <x86intrin.h>
88 ///
89 /// This intrinsic corresponds to the \c LZCNT instruction.
90 ///
91 /// \param __X
92 /// An unsigned 64-bit integer whose leading zeros are to be counted.
93 /// \returns An unsigned 64-bit integer containing the number of leading zero
94 /// bits in the operand.
95 /// \see _lzcnt_u64
96 static __inline__ unsigned long long __DEFAULT_FN_ATTRS
97 __lzcnt64(unsigned long long __X)
98 {
99  return __X ? __builtin_clzll(__X) : 64;
100 }
101 
102 /// Counts the number of leading zero bits in the operand.
103 ///
104 /// \headerfile <x86intrin.h>
105 ///
106 /// This intrinsic corresponds to the \c LZCNT instruction.
107 ///
108 /// \param __X
109 /// An unsigned 64-bit integer whose leading zeros are to be counted.
110 /// \returns An unsigned 64-bit integer containing the number of leading zero
111 /// bits in the operand.
112 /// \see __lzcnt64
113 static __inline__ unsigned long long __DEFAULT_FN_ATTRS
114 _lzcnt_u64(unsigned long long __X)
115 {
116  return __X ? __builtin_clzll(__X) : 64;
117 }
118 #endif
119 
120 #undef __DEFAULT_FN_ATTRS
121 
122 #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:79
static __inline__ unsigned int __DEFAULT_FN_ATTRS __lzcnt32(unsigned int __X)
Counts the number of leading zero bits in the operand.
Definition: lzcntintrin.h:62
#define __DEFAULT_FN_ATTRS
Definition: lzcntintrin.h:32