1 #ifndef X86_BUILTIN_CTZ_H 2 #define X86_BUILTIN_CTZ_H 3 4 #if defined(_MSC_VER) && !defined(__clang__) 5 #if defined(_M_IX86) || defined(_M_AMD64) || defined(_M_IA64) || defined(_M_ARM) || defined(_M_ARM64) 6 7 #include <intrin.h> 8 #ifdef X86_FEATURES 9 # include "arch/x86/x86.h" 10 #endif 11 12 /* This is not a general purpose replacement for __builtin_ctz. The function expects that value is != 0 13 * Because of that assumption trailing_zero is not initialized and the return value of _BitScanForward is not checked 14 */ __builtin_ctz(uint32_t value)15static __forceinline unsigned long __builtin_ctz(uint32_t value) { 16 #ifdef X86_FEATURES 17 if (x86_cpu_has_tzcnt) 18 return _tzcnt_u32(value); 19 #endif 20 unsigned long trailing_zero; 21 _BitScanForward(&trailing_zero, value); 22 return trailing_zero; 23 } 24 #define HAVE_BUILTIN_CTZ 25 26 #ifdef _M_AMD64 27 /* This is not a general purpose replacement for __builtin_ctzll. The function expects that value is != 0 28 * Because of that assumption trailing_zero is not initialized and the return value of _BitScanForward64 is not checked 29 */ __builtin_ctzll(uint64_t value)30static __forceinline unsigned long long __builtin_ctzll(uint64_t value) { 31 #ifdef X86_FEATURES 32 if (x86_cpu_has_tzcnt) 33 return _tzcnt_u64(value); 34 #endif 35 unsigned long trailing_zero; 36 _BitScanForward64(&trailing_zero, value); 37 return trailing_zero; 38 } 39 #define HAVE_BUILTIN_CTZLL 40 #endif 41 42 #endif 43 #endif 44 #endif 45