1 /*===---- lzcntintrin.h - LZCNT intrinsics ---------------------------------===
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21 *===-----------------------------------------------------------------------===
24 #if !defined __X86INTRIN_H && !defined __IMMINTRIN_H
25 #error "Never use <lzcntintrin.h> directly; include <x86intrin.h> instead."
28 #ifndef __LZCNTINTRIN_H
29 #define __LZCNTINTRIN_H
31 /* Define the default attributes for the functions in this file. */
32 #define __DEFAULT_FN_ATTRS __attribute__((__always_inline__, __nodebug__, __target__("lzcnt")))
34 /// \brief Counts the number of leading zero bits in the operand.
36 /// \headerfile <x86intrin.h>
38 /// This intrinsic corresponds to the \c LZCNT instruction.
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)
47 return __X ? __builtin_clzs(__X) : 16;
50 /// \brief Counts the number of leading zero bits in the operand.
52 /// \headerfile <x86intrin.h>
54 /// This intrinsic corresponds to the \c LZCNT instruction.
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)
63 return __X ? __builtin_clz(__X) : 32;
66 /// \brief Counts the number of leading zero bits in the operand.
68 /// \headerfile <x86intrin.h>
70 /// This intrinsic corresponds to the \c LZCNT instruction.
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)
79 return __X ? __builtin_clz(__X) : 32;
83 /// \brief Counts the number of leading zero bits in the operand.
85 /// \headerfile <x86intrin.h>
87 /// This intrinsic corresponds to the \c LZCNT instruction.
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)
96 return __X ? __builtin_clzll(__X) : 64;
99 /// \brief Counts the number of leading zero bits in the operand.
101 /// \headerfile <x86intrin.h>
103 /// This intrinsic corresponds to the \c LZCNT instruction.
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)
112 return __X ? __builtin_clzll(__X) : 64;
116 #undef __DEFAULT_FN_ATTRS
118 #endif /* __LZCNTINTRIN_H */