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re: how to tell if a process is 64-bit

Thor Lancelot Simon writes:
> On Sun, Sep 10, 2017 at 03:29:22PM +0000, wrote:
> > 
> > MIPS has four ABIs, if you include "O64".  Whether a particular OS allows
> > all four concurrently is another matter; it isn't clear that would make
> > sense.  Mixing "O" and "N" ABIs is rather messy.
> > 
> > Would you call N32 a 64-bit ABI?  It has 64 bit registers, so if a value
> > is passed to the kernel in a register it comes across as 64 bits.  But it
> > has 32 bit addresses.
> I wouldn't, because if an address is passed to the kernel, it comes across
> as 32 bits.  But what _do_ we do on modern, 32-bit MIPS?  Are we still O32?
> It does kind of look like it -- all our 32-bit MIPS ports' sets files seem
> to be linked to ../../../shared/mipsel/ which must be O32 since it is also
> used for the pmax sets.

as i mentioned earlier in this thread, our mips64 defaults to n32
userland for everything except kvm-only using utils (that all need
to be fixed.)

o32, n32 and n64 all are supported, though n64 dynamic is currently
broken for some reason i haven't looked closely at.

any mips port without "64" in it is o32-only, because it's built to
only support a 32 bit register-size CPU.


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