Modulo Bug?

[Thiez]

On Saturday, 11 August 2012 at 17:15:21 UTC, Norbert Nemec wrote:
> On 11.08.2012 18:13, bearophile wrote:
>> David:
>>
>>> Thanks! I thought modulo should alawys yield the same ... 
>>> seems like I
>>> was wrong ;)
>>
>> It's C design that's wrong.
>
> And it's the processor design that makes it inefficient to 
> correct it nowadays.
>
> Python's definition of modulo is far more useful than C's. 
> Implemented in machine code, however, it takes several 
> additional commands because the integer division is hardwired 
> to the C definition. I guess that hardware integer division in 
> processors became popular only when C was already widely in use.

A few extra instructions (a CMOV followed by ADD should suffice, 
yes?) seems like a small price to pay if it can prevent bugs. Why 
hasn't the Python-modulo been made the default back when D was 
designed? The ever-so-slightly more efficient C-modulo could be 
provided in a library. Of course it's way too late to change it 
now...