LibOpCtPopNP

Git Source

An opcode that counts the number of bits set in a word. This is called ctpop because that's the name of this kind of thing elsewhere, but the more common name is "population count" or "Hamming weight". The word in the standard ops lib is called bitwise-count-ones, which follows the Rust naming convention. There is no evm opcode for this, so we have to implement it ourselves.

Functions

integrity

ctpop unconditionally takes one value and returns one value.

function integrity(IntegrityCheckStateNP memory, Operand) internal pure returns (uint256, uint256);

run

Output is the number of bits set to one in the input. Thin wrapper around LibCtPop.ctpop.

function run(InterpreterStateNP memory, Operand, Pointer stackTop) internal pure returns (Pointer);

referenceFn

The reference implementation of ctpop.

function referenceFn(InterpreterStateNP memory, Operand, uint256[] memory inputs)
    internal
    pure
    returns (uint256[] memory);