[Python-Dev] Drop support for ones' complement machines?

Mark Dickinson dickinsm at gmail.com
Tue Dec 1 17:24:08 CET 2009


On Tue, Dec 1, 2009 at 4:17 PM, James Y Knight <foom at fuhm.net> wrote:
> I think all that needs to be defined is that conversion from unsigned to signed, and (negative) signed to unsigned integers have 2's complement wrapping semantics, and does not affect the bit pattern in memory.

Yes, I think everything does pretty much follow from this, since for ones'
complement or sign-and-magnitude these wrapping semantics are impossible,
because the signed type doesn't have enough distinct possible values.

> Stating it that way makes it clearer that all you're assuming is the operation of the cast operators, and it seems to me that it implies the other requirements.

Agreed.

Thanks,

Mark


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