Messages in this thread | | | Date | Sat, 30 Nov 2002 21:34:31 +0100 | From | Ralf Baechle <> | Subject | Re: [PATCH] Start of compat32.h (again) |
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On Wed, Nov 27, 2002 at 09:29:18AM +0100, Andi Kleen wrote:
> > That is not a safe assumption. The ia64 ABI requires that a 32-bit > > result is returned in the least-significant 32 bits only---the upper > > 32 bits may contain garbage. It should be safe to declare the syscall > > return type always as "long", no? > > But the 32bit user space surely doesn't care about any garbage in > the upper 32bits, no ?
It does. With very few exceptions all 32-bit instructions on MIPS require that all the register values are properly sign extended to 64-bit or the operation of those instructions is undefined.
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