`.quad BIGNUMS'
===============
`.quad' expects zero or more bignums, separated by commas. For each
bignum, it emits an 8-byte integer. If the bignum won't fit in 8
bytes, it prints a warning message; and just takes the lowest order 8
bytes of the bignum.
The term "quad" comes from contexts in which a "word" is two bytes;
hence _quad_-word for 8 bytes.