ppc405_dma warnings
Armin
akuster at pacbell.net
Thu Mar 14 08:04:02 EST 2002
David Gibson wrote:
> Armin,
>
> ppc405_dma.c has several constructs like:
> p_dma_ch->polarity = polarity & GET_DMA_POLARITY(0);
> where GET_DMA_POLARITY() is defined:
> #define GET_DMA_POLARITY(chan) DMAReq##chan##_ActiveLow | \
> DMAAck##chan##_ActiveLow | EOT##chan##_ActiveLow
>
> Note the macro has no parentheses around its definition, which is
> unusual. IIRC C precedence will mean this code turns out as:
> p_dma_ch->polarity = (polarity & DMAReq0_ActiveLow) | \
> DMAAck0_ActiveLow | EOT0_ActiveLow
> which looks wrong to me and if correct is an insane use of a macro.
> It's also giving compiler warnings.
>
> I'm guessing that the macro should just get parentheses, but that's a
> semantic change so I don't want to make it without knowing for sure.
> Could you check this?
>
> --
> David Gibson | For every complex problem there is a
> david at gibson.dropbear.id.au | solution which is simple, neat and
> | wrong. -- H.L. Mencken
> http://www.ozlabs.org/people/dgibson
>
>
>
>
>
Thanks.. I missed the parentheses. The macro is there to allow me to
use the same driver for the 405gp dma and the stb0xxxx cpu since the the
stbxxxx does not have a polarity. I could have poluted the driver with
#ifdefs or mask the deltas with a few macros. I went with macros.
armin
PS I am insane
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