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 /// 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 /// 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.
61 static __inline__ unsigned int __DEFAULT_FN_ATTRS
62 __lzcnt32(unsigned int __X)
64 return __X ? __builtin_clz(__X) : 32;
67 /// Counts the number of leading zero bits in the operand.
69 /// \headerfile <x86intrin.h>
71 /// This intrinsic corresponds to the \c LZCNT instruction.
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.
78 static __inline__ unsigned int __DEFAULT_FN_ATTRS
79 _lzcnt_u32(unsigned int __X)
81 return __X ? __builtin_clz(__X) : 32;
85 /// Counts the number of leading zero bits in the operand.
87 /// \headerfile <x86intrin.h>
89 /// This intrinsic corresponds to the \c LZCNT instruction.
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.
96 static __inline__ unsigned long long __DEFAULT_FN_ATTRS
97 __lzcnt64(unsigned long long __X)
99 return __X ? __builtin_clzll(__X) : 64;
102 /// Counts the number of leading zero bits in the operand.
104 /// \headerfile <x86intrin.h>
106 /// This intrinsic corresponds to the \c LZCNT instruction.
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.
113 static __inline__ unsigned long long __DEFAULT_FN_ATTRS
114 _lzcnt_u64(unsigned long long __X)
116 return __X ? __builtin_clzll(__X) : 64;
120 #undef __DEFAULT_FN_ATTRS
122 #endif /* __LZCNTINTRIN_H */