Scripts should be fine as long as they don't make a typo <cough>
1. When input reaches the range near 2^1024 where doubles mode just returns 0, $modinv triggers a GPF
2. OK. If replace $modinv with $gcd, it switches to returning 0 instead of 1, I assume because the overmax value evalues as zero.
3. OK. If replace $modinv with $powmod(2,65537,%gpfcrash) it switches to zeroes around 2^55 which is fine, since accuracy in doubles mode can't be expected above modulus=sqrt(2^53)
4. Not sure which is the better choice for results in this range, returning 0 or blank or maybe -1. If replace with $cbrt(%gpfcrash) or $log2(%gpfcrash) they return blank in that range instead of zeroes. But if replace with $lcm(911,%gpfcrash), it returns zeroes in that range, but there's also a gap of $null outputs between the numbers having 53 bits of precision and where it begins to return zero