Developer Guide and Reference

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_lzcnt_u32/64

Counts the number of leading zero bits in a source operand. Returns operand size as output when source operand is zero. The corresponding Intel® AVX2 instruction is
LZCNT
.

Syntax

extern unsigned int _lzcnt_u32(unsigned int source);
extern unsigned __int64 _lzcnt_u64(unsigned __int64 source);
Arguments
source
the source operand used for the operation
Description
Counts the number of leading most significant zero bits in a source operand returning the result into a destination when source operand is 0.
Returns
Result of the operation.