CountLeadingZero

Applicability

Product	Supported
Atlas 350 Accelerator Card	√
Atlas A3 training product/Atlas A3 inference product	√
Atlas A2 training product/Atlas A2 inference product	√
Atlas 200I/500 A2 inference product	x
Atlas inference product AI Core	√
Atlas inference product Vector Core	x
Atlas training product	x

Function Usage

Computes the number of leading 0s of an uint64_t number (number of 0s from the most significant bit to the first 1 in the binary number).

Prototype

__aicore__ inline int64_t CountLeadingZero(uint64_t valueIn)

Parameters

**Table 1** Parameters
Parameter	Input/Output	Description
valueIn	Input	A binary number.

Returns

Return the number of leading zeros in valueIn.

Constraints

None

Example

uint64_t valueIn = 0x0fffffffffffffff;
// Output (ans): 4 There are four 0s from the most significant bit to the first 1 in the binary number.
int64_t ans = AscendC::CountLeadingZero(valueIn);

Parent topic: Scalar Computation