Re: long long considered harmful?

["Kris Warkentin" <kewarken at qnx dot com>]

<disclaimer> I didn't write this stuff - it's taken from our system headers
and reflects the way that the kernel stores registers when you ask it to.
</disclaimer>

> > typedef union
> > {
> >   unsigned long long u64;
> >   double f;
> > } mipsfloat;
>
> This is a target entity isn't it?  You've got no business using
> "double" for a target float.  Use the gdb type mechanism instead.

Can you point to an example of how this is done?

> > typedef struct mips_cpu_registers
> > {
> >   unsigned regs[74];
> >   unsigned long long regs_alignment;
> > } MIPS_CPU_REGISTERS;
>
> What's the purpose of the alignment entry?  I doubt it does what you
> want it to.

I believe it's padding to handle whether we're dealing with a little or big
endian target.  I'll ask the kernel guys when I find them.  Regardless of
whether it does anything, the structure has to be the appropriate size for
the kernel to fill in.  "Mine is not to reason why, mine is just to do or
die."

> > #ifdef __BIGREGS__
>
> Eh?

Not sure about the origin of this.  It's in our powerpc stuff but there
doesn't ever seem to be a situation where it's defined.  It might be future
proofing but it probably doesn't belong here.  I'll most likely take it out
and if it ever comes up, fix it in the target backend.

> I recommend something like 'typedef char qnx_reg64[8];'; then you can
> still say 'qnx_reg64 gpr[32]' and get the right result.

Really?  I thought I knew C fairly well....I didn't think that was legal.
If so, it handles my ugliness issues.

cheers,

Kris