64-bit unsigned integer arithmetic and logic operators for JavaScript. Implemented using big endian arrays of two signed 32-bit integers.
Used in js-hash. For the 32-bit counterpart, see arithmetic-type/uint32.
let a = get64(0, 1) ;
rotr64(a, 1); // [-1, 0]
let x = get64(0xFFFFFFFF, 0xFFFFFFFF);
add64(x, x); // [-1, -2]
