According to documentation, perl's Math::BigInt does floored division,
i.e. the bdiv function does 1 / -4 = -1. OpenSSL's BN_div, as well as
bc, do truncated division, i.e. 1 / -4 = 0.
We need to compensate for that difference in test/recipes/bc.pl to
make sure to verify the bntest results under its own conditions, by
dividing the absolute values of the given numbers and fixup the
result's negativity afterwards.
Closes RT#4485
Reviewed-by: Viktor Dukhovni <viktor@openssl.org>
The math recipes are among the heavier, but also quite important.
For the BN test, we have previously relied on bc to verify the numbers.
Unfortunately, bc doesn't exist everywhere, making tests on some platforms
rather painful. With the new recipe (recipes/10-test_bn.t), we rely
on perl's Math::BigInt and a homegrown simple calculator (recipes/bc.pl)
that can do enough to cover for bc.
Reviewed-by: Rich Salz <rsalz@openssl.org>
