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| author | Richard Levitte <levitte@openssl.org> | 2016-03-26 00:07:50 +0100 |
|---|---|---|
| committer | Richard Levitte <levitte@openssl.org> | 2016-03-27 21:39:23 +0200 |
| commit | ce84456ddf4e57c18a84858755b8b90c183a270e (patch) | |
| tree | f9813827b1dd4fc2c4bca43afeb11dc9d9c0037b | |
| parent | c828cd7cd0426dde10b07e7b68f3741a5ea91fc6 (diff) | |
| download | openssl-ce84456ddf4e57c18a84858755b8b90c183a270e.tar.gz | |
Math::BigInt does floored divs, BN_div does truncated div, compensate
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>
| -rw-r--r-- | test/recipes/bc.pl | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/test/recipes/bc.pl b/test/recipes/bc.pl index 29a4a8a84a..f7d4dc681d 100644 --- a/test/recipes/bc.pl +++ b/test/recipes/bc.pl @@ -46,7 +46,16 @@ sub __multiplier { if ($operator eq "*") { $operand1->bmul($operand2); } elsif ($operator eq "/") { + # Math::BigInt->bdiv() is documented to do floored division, + # i.e. 1 / -4 = -1, while bc and OpenSSL BN_div do truncated + # division, i.e. 1 / -4 = 0. We need to make the operation + # work like OpenSSL's BN_div to be able to verify. + my $neg = ($operand1->is_neg() + ? !$operand2->is_neg() : $operand2->is_neg()); + $operand1->babs(); + $operand2->babs(); $operand1->bdiv($operand2); + if ($neg) { $operand1->bneg(); } } elsif ($operator eq "%") { # Here's a bit of a quirk... # With OpenSSL's BN, as well as bc, the result of -10 % 3 is -1 |