On 9/27/21 04:21, Bin Meng wrote:
> 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);
AFAIK in C logical NOT has precedence over bitwise AND, so IIUC
compilers should read the current code as:
claimed (!!s->chan[ch].control) & CONTROL_CLAIM;
meaning this patch is doing more than "improve code readability",
this is a logical change and likely a bug fix...
BTW GCC suggestions are:
claimed (!!s->chan[ch].control) & CONTROL_CLAIM;
claimed (!!s->chan[ch].control) && CONTROL_CLAIM;
>
> if (!claimed && (value & CONTROL_CLAIM)) {
> /* reset Next* registers */
>
