double-double/src/double-representation/lsb-exponent.ts

Pure double-double precision functions *with strict error bounds*.

import { getLowestSetBit } from "./get-max-set-bit.js";
import { exponent } from "./exponent.js";


/**
 * Returns the true exponent of the lsb that is set of the given number or
 * NaN if a === 0 or +-inf or NaN.
 * @param a An array of numbers to check
 */
function lsbExponent(a: number) {
    if (a === 0 || !Number.isFinite(a)) { 
        return NaN; 
    }

    const e = exponent(a);

    return getLowestSetBit(a) - 52 + e;
}


export { lsbExponent }