Re: [Qemu-devel] [RFC][MIPS][PATCH 3/6] Initial support of VIA IDE controller used by fulong mini pc

[Markus Armbruster]

Blue Swirl <address@hidden> writes:

> On 5/11/10, Markus Armbruster <address@hidden> wrote:
>> Blue Swirl <address@hidden> writes:
>>
>>  > On 5/9/10, chen huacai <address@hidden> wrote:
>>  >> This patch add initial support of VIA IDE controller used by fulong mini 
>> pc
>>  >>
>>  >>  Signed-off-by: Huacai Chen <address@hidden>
>>  >>  -----
>>  [...]
>>
>> >>  diff --git a/hw/ide/via.c b/hw/ide/via.c
>>  >>  new file mode 100644
>>  >>  index 0000000..9adc5b5
>>  >>  --- /dev/null
>>  >>  +++ b/hw/ide/via.c
>>  >>  @@ -0,0 +1,189 @@
>>
>> [...]
>>
>> >>  +static void bmdma_writeb(void *opaque, uint32_t addr, uint32_t val)
>>  >>  +{
>>  >>  +    BMDMAState *bm = opaque;
>>  >>  +#ifdef DEBUG_IDE
>>  >>  +    printf("bmdma: writeb 0x%02x : 0x%02x\n", addr, val);
>>  >>  +#endif
>>  >>  +    switch(addr & 3) {
>>  >>  +    case 2:
>>  >>  +        bm->status = (val & 0x60) | (bm->status & 1) | (bm->status &
>>  >>  ~val & 0x06);
>>  >>  +        break;
>>  >
>>  > Some gccs complain if there is no default case.
>>
>>
>> Are you sure?  Which version?
>>
>>  It warns when the switch expression's type is an enumeration, and the
>>  switch doesn't handle all enumeration constants, and has no default
>>  case.
>>
>>  I can be made to warn whenever there's no default, but we don't do that.
>
> This problem came up with 299b520cd4092be3c53f8380b81315c33927d9d3
> (fixed before commit) and 4450521668471c7685551d8c5bcc582d754e9843,
> with mingw gcc and OpenBSD gccs.
[...]
>
> Maybe those cases were different from this.

The first commit you quoted is indeed different: the default prevents a
spurious warning: ‘context’ may be used uninitialized in this function
from some versions of gcc.  No such confusion can arise here.

In the second one, the switch expression is of enumeration type.