[U-Boot] [PATCH] ppc4xx: Enable support for 64bit printf on all PPC4xx variants

[Jerry Van Baren <gvb.uboot@gmail.com>]

Scott Wood wrote:
> Wolfgang Denk wrote:
>>>> I hope we don't have any more such #defines hidden in other header
>>>> files?
>>> I vote for completely removing these defines then (or at least 
>>> CONFIG_SYS_64BIT_VSPRINTF) and by this enabling the 64bit printf format for 
>>> all boards. I myself have hunted problems disguised by incorrect 64bit 
>> I don't want this because of the memory footprint.

[snip]

> There could also be some warning from printf() if %ll 
> is used when not supported, and/or it could still check for %ll and pop 
> a long long from the varargs but discard the high half.
> 
> -Scott

Regardless of the in/out debate, we should print a warning if %ll is 
used but not supported.  I would suggest simply printing the "%lld" (or 
whatever the format is) and pop two longs from the varargs.  That would 
make it clear something is missing and probably wrong.

I don't like printing half and discarding half: it will be erroneous 
with no warning if the upper half != 0.  It would also have endian 
complications since the half you want to discard depends on the 
machine's endianness (not insurmountable).

One possible enhancement is to special-case %ll[0-9]*[Xx] and treat it 
as as two %08lx formats.  Hmmm, this would need correct endian handling 
too. :-/

Best regards,
gvb