[phobos] [D-Programming-Language/phobos] 9ecf94: 5568 A problem with BigInt modulus

[Don Clugston]

It's that bloddy -release in the makefile has crept in again into my
branch (and maybe into Walter's as well). Sorry, I'm not going to have
ANY time for D until next week. Please revert the changes, or comment
out the failing tests I added to std.bigint.


On 23 February 2011 22:41, Brad Roberts <braddr at puremagic.com> wrote:
> Looks like the biguintcore unit tests are pissed off, across the board (well, I'm assuming freebsd will eventually show
> the same problem, it's not caught up yet).
>
> On 2/23/2011 1:14 PM, noreply at github.com wrote:
>> Branch: refs/heads/master Home:   https://github.com/D-Programming-Language/phobos
>>
>> Commit: 9ecf947290f1149e1b062a75dafd30326697fe00
>> https://github.com/D-Programming-Language/phobos/commit/9ecf947290f1149e1b062a75dafd30326697fe00 Author: Don Clugston
>> <dclugston at googlemail.com> Date:   2011-02-23 (Wed, 23 Feb 2011)
>>
>> Changed paths: M std/bigint.d M std/internal/math/biguintcore.d
>>
>> Log Message: ----------- 5568 A problem with BigInt modulus
>>
>> This is quite subtle. The recursive division algorithm has a possibility of one bit of overflow in the second
>> recursive call, in cases where the top quarter of the dividend is identical to the top half of the divisor. The
>> description of the recursive division algorithm in "Modern Computer Arithmetic" 0.5.9 is rather vague about this
>> (which is why I missed it originally, though the test case does cause assert failure in biguint). Unfortunately it
>> requires fairly substantial changes to the function, which makes the algorithm a lot less elegant. But I have managed
>> to implement it without any change to the basic division algorithm (which is very fast).
>>
>>
>> Commit: 9fa7393417015257342401860ea4a2fa4f55db41
>> https://github.com/D-Programming-Language/phobos/commit/9fa7393417015257342401860ea4a2fa4f55db41 Author: Walter
>> Bright <walter at walterbright.com> Date:   2011-02-23 (Wed, 23 Feb 2011)
>>
>> Changed paths: M std/bigint.d M std/internal/math/biguintcore.d
>>
>> Log Message: ----------- Merge branch 'bigint5568' of https://github.com/donc/phobos into donc-bigint5568
>>
>>
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