Hi Markus, On Mon, Sep 27, 2021 at 2:51 PM Markus Armbruster <arm...@redhat.com> wrote: > > Bin Meng <bmeng...@gmail.com> writes: > > > GCC seems to be strict about processing pattern like "!!for & bar". > > When 'bar' is not 0 or 1, it complains with -Werror=parentheses: > > > > suggest parentheses around operand of ‘!’ or change ‘&’ to ‘&&’ or ‘!’ to > > ‘~’ [-Werror=parentheses] > > > > Add a () around "foo && bar", which also improves code readability. > > > > Signed-off-by: Bin Meng <bmeng...@gmail.com> > > --- > > > > hw/dma/sifive_pdma.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/hw/dma/sifive_pdma.c b/hw/dma/sifive_pdma.c > > index b4fd40573a..b8ec7621f3 100644 > > --- a/hw/dma/sifive_pdma.c > > +++ b/hw/dma/sifive_pdma.c > > @@ -243,7 +243,7 @@ static void sifive_pdma_write(void *opaque, hwaddr > > offset, > > offset &= 0xfff; > > switch (offset) { > > case DMA_CONTROL: > > - claimed = !!s->chan[ch].control & CONTROL_CLAIM; > > + claimed = !!(s->chan[ch].control & CONTROL_CLAIM); > > > > if (!claimed && (value & CONTROL_CLAIM)) { > > /* reset Next* registers */ > > Old code > > first double-negate, mapping zero to zero, non-zero to one > then mask, which does nothing, because CONTROL_CLAIM is 1 > > New code: > > first mask, yielding 0 or 1 > then double-negate, which does nothing > > Looks like a bug fix to me. If I'm right, the commit message is wrong, > and the double negate is redundant. >
Thanks for the review. The double negate is not needed with CONTROL_CLAIM which is 1, but is needed if the bit is in another position. Regards, Bin