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

> On Sep 10, 2017, at 10:31 AM, Thor Lancelot Simon <> wrote:
> On Fri, Sep 08, 2017 at 07:38:24AM -0400, Mouse wrote:
>>> In a cross-platform process utility tool the question came up how to
>>> decide if a process is 64-bit.
>> First, I have to ask: what does it mean to say that a particular
>> process is - or isn't - 64-bit?
> I think the only simple answer is "it is 64-bit in the relevant sense if
> it uses the platform's 64-bit ABI for interaction with the kernel".
> This actually raises a question for me about MIPS: do we have another
> process flag to indicate O32 vs. N32, or can we simply not run O32
> executables on 64-bit or N32 kernels (surely we don't use the O32 ABI
> for all kernel interaction by 32-bit processes)?

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.


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