Should % ever "overflow"?

[deadalnix via Digitalmars-d]

On Sunday, 26 June 2016 at 04:25:07 UTC, "Smoke" Adams wrote:
>> Languages:
>> C#: https://msdn.microsoft.com/en-us/library/0w4e0fzs.aspx
>> Java: 
>> https://docs.oracle.com/javase/specs/jls/se7/html/jls-15.html#jls-15.17.3
>> C11: 
>> http://www.open-std.org/jtc1/sc22/wg14/www/docs/C99RationaleV5.10.pdf (See 6.5.5 for update on % operator, mentioning, example at 7.20.6).
>> Python2: https://docs.python.org/2/reference/expressions.html
>> Python3: https://docs.python.org/3/reference/expressions.html
>>
>> CPUs:
>> Arm7(eeabi): 
>> https://github.com/wayling/xboot-clone/blob/master/src/arch/arm/lib/gcc/__aeabi_idivmod.S
>> Arm7(Darwin): 
>> http://opensource.apple.com//source/clang/clang-163.7.1/src/projects/compiler-rt/lib/arm/modsi3.S
>> Mips: 
>> http://www.mrc.uidaho.edu/mrc/people/jff/digital/MIPSir.html 
>> (See DIV instruction)
>> X86: http://x86.renejeschke.de/html/file_module_x86_id_137.html
>>
>> Now I'm sure there are a weird CPU that isn't produced since 
>> the 80s and that D will never support that do it in some other 
>> way, but for all platforms that matter today, this isn't the 
>> case.
>>
>> This is not MY definition, this is the definition everybody 
>> except you uses? Even PHP get this right 
>> (http://php.net/manual/en/language.operators.arithmetic.php).
>>
>> Now champion, what do you have supporting your definition ?
>

> http://mathworld.wolfram.com/Congruence.html
> https://en.wikipedia.org/wiki/Modulo_operation
> https://en.wikipedia.org/wiki/Modular_arithmetic
> http://stackoverflow.com/questions/1082917/mod-of-negative-number-is-melting-my-brain
> https://www.securecoding.cert.org/confluence/pages/viewpage.action?pageId=6422581
> http://www.mathworks.com/help/matlab/ref/mod.html?requestedDomain=www.mathworks.com
>

Except for mathematica, these are all irrelevant. The claim is 
that programming languages and CPU define % in some way, not that 
mathematician do it the same way.

Please read this again (you may want to use you finger to make 
sure you) :

>>>> This isn't a proof, this is a definition. This is the 
>>>> definition that is used by all programming languages out 
>>>> there and all CPUs. It isn't going to change because someone 
>>>> on the internet think he has a better definition that 
>>>> provide no clear advantage over the current one.

You mention you had information supporting that this was not 
true. It is very easy to debunk. You could for instance provide a 
link to a CPU that do NOT do the % operation that way. I was able 
to demonstrate to you that all major CPUs and many major 
languages do it that way (see there is a claim and evidence to 
support it, it is how arguing works). The best you've been able 
to present is a DSL (mathematica) and no CPU.

Bonus points for the stackoverflow question, which isn't a spec 
and supports my point: languages and CPU do it that way. Once 
again, it is to wonder if you actually understand what you are 
responding to.

> Of course, I don't expect a neanderthal like yourself to 
> understand that. Have fun lemming.
>
> Oh, hey, I'm going to define that your an idiot! Thanks for 
> agreeing with me.

I see I've hurt your feelings. That's ok, you'll survive. Next 
time, try make sure to understand the difference between a 
definition and a proof, and I won't have to point to you, and 
your feeling won't be hurt next time.