General gcc4.0 porting guide

[Ignacio Vazquez-Abrams]

On Fri, 2005-04-29 at 17:08 +0200, Hans de Goede wrote:
> Ignacio Vazquez-Abrams wrote:
> > On Fri, 2005-04-29 at 15:32 +0200, Matthias Saou wrote: 
> > 
> >>Hmmm, so I guess the patch I've made for libmpeg3 is wrong. What would the
> >>proper fix for this be, then?
> >>
> >>      *((unsigned short*)data)++ = \
> >>               ((CLIP(r_l) & 0xf8) << 8) | \
> >>               ((CLIP(g_l) & 0xfc) << 3) | \
> >>               ((CLIP(b_l) & 0xf8) >> 3);
> > 
> > 
> > Possibly:
> > 
> >       *((unsigned short*)data) = \
> >                ((CLIP(r_l) & 0xf8) << 8) | \
> >                ((CLIP(g_l) & 0xfc) << 3) | \
> >                ((CLIP(b_l) & 0xf8) >> 3);
> >       data += sizeof(unsigned short) / sizeof(*data);
> > 
> > or:
> > 
> >       register unsigned short newdata = \
> >                ((CLIP(r_l) & 0xf8) << 8) | \
> >                ((CLIP(g_l) & 0xfc) << 3) | \
> >                ((CLIP(b_l) & 0xf8) >> 3);
> >       data++ = (unsigned char)((newdata >> 8) & 0xff);
> >       data++ = (unsigned char)(newdata & 0xff);
> > 
> 
> this assumes MSB endianness (so won't work on intel)

True enough. But easy to handle.

> and that data is a (unsigned) char *, which has not been stated.

I checked the code, and yes it is.

> Also you probably mean "*data++ =" not "data++ ="

Right, my bad.

-- 
Ignacio Vazquez-Abrams <ivazquez at ivazquez.net>
http://fedora.ivazquez.net/

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