deps/v8/src/js/harmony-atomics.js
function ValidateIndex(index, length) {
  var numberIndex = TO_NUMBER(index);
  var accessIndex = TO_INTEGER(numberIndex);
  if (numberIndex !== accessIndex) {
    throw MakeRangeError(kInvalidAtomicAccessIndex);
  }
  if (accessIndex < 0 || accessIndex >= length) {
    throw MakeRangeError(kInvalidAtomicAccessIndex);
  }
  return accessIndex;
}
function ValidateIndex(index, length) {
  var numberIndex = TO_NUMBER(index);
  var accessIndex = TO_INTEGER(numberIndex);
  if (numberIndex !== accessIndex) {
    throw MakeRangeError(kInvalidAtomicAccessIndex);
  }
  if (accessIndex < 0 || accessIndex >= length) {
    throw MakeRangeError(kInvalidAtomicAccessIndex);
  }
  return accessIndex;
}
https://tc39.github.io/ecmascript_sharedmem/shmem.html#Atomics.ValidateAtomicAccess