# _blsmsk_u32/64

Sets all the lower bits of the destination to “1” up to and including lowest set bit (=1) in the source operand. The corresponding Intel® AVX2 instruction is BLSMSK.

## Syntax

extern unsigned int _blsmsk_u32(unsigned int s1);

extern unsigned __int64 _blsmsk_u64(unsigned __int64 s1);

## Arguments

s1 | the source operand used for the operation

## Description

Sets all the lower bits of the destination to “1” up to and including lowest set bit (=1) in the source operand. If source operand is 0, all bits of the destination are set to 1.

## Returns

Result of the operation

Parent topic: Intrinsics for Operations to Manipulate Integer Data at Bit-Granularity