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The x32 system call ABI

Posted Apr 15, 2012 23:05 UTC (Sun) by khim (subscriber, #9252)
In reply to: The x32 system call ABI by tenchiki
Parent article: The x32 system call ABI

One of the notable specs for the n32 ABI that don't seem to have been mentioned for x32 is to make the long datatype to be 64bits

Why would anyone want this? x32 uses ILP32 model to minimize difference between IA32 mode and x32 mode. Any other choice just looks… strange.

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Posted Apr 16, 2012 6:56 UTC (Mon) by paulj (subscriber, #341) [Link]

Because it lets you have access to the 64bit arithmetic capabilities of the hardware, even when you don't need the 64bit addressing capabilities.

The x32 system call ABI

Posted Apr 16, 2012 9:00 UTC (Mon) by khim (subscriber, #9252) [Link]

What's wrong with using long long for that?

The x32 system call ABI

Posted Apr 16, 2012 11:07 UTC (Mon) by paulj (subscriber, #341) [Link]

Hmm, good point. Actually, I think in IRIX n32 it was indeed "long long" that was 64bit! (Making 64bit long risked breaking software that assumed sizeof(long) == sizeof(void *) and tried to store longs in pointers).