Re: [Qemu-devel] [PATCH for-1.1? v2] slirp: Avoid statements without effect on Big Endian host
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Am 28.05.2012 13:47, schrieb Jan Kiszka:
> On 2012-05-28 00:10, Peter Maydell wrote:
>> On 27 May 2012 17:42, Andreas Färber
>> wrote:
>>> +# if defined(__APPLE__) +# undef NTOHL +# undef NTOHS +#
>>> undef HTONL +# undef HTONS +# define NTOHL(d) do { } while
>>> (0) +# define NTOHS(d) do { } while (0) +# define HTONL(d) do
>>> { } while (0) +# define HTONS(d) do { } while (0) +# else
>>
>> We could just use this for everything, not just if __APPLE__,
>> right? For big-endian the semantics we want are always "do
>> nothing" so it's always OK to undef and redefine... That would
>> save having a special case.
>
> Yes, please.
On second thoughts my v2 was totally unnecessary and the solution
flawed: The HTONS(x); warning is stemming from Apple's
#define HTONS(d) (d)
not from our
#define HTONS(d)
so we can just unconditionally #undef the existing definitions.
That'll lead to unnecessary semicolons but not to warnings.
Andreas
- --
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg
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Re: [Qemu-devel] [PATCH for-1.1? v2] slirp: Avoid statements without effect on Big Endian host
Am 28.05.2012 14:00, schrieb Peter Maydell:
> On 28 May 2012 12:47, Jan Kiszka wrote:
>> On 2012-05-28 00:10, Peter Maydell wrote:
>>> On 27 May 2012 17:42, Andreas Färber wrote:
+# if defined(__APPLE__)
+# undef NTOHL
+# undef NTOHS
+# undef HTONL
+# undef HTONS
+# define NTOHL(d) do { } while (0)
+# define NTOHS(d) do { } while (0)
+# define HTONL(d) do { } while (0)
+# define HTONS(d) do { } while (0)
+# else
>>>
>>> We could just use this for everything, not just if __APPLE__,
>>> right? For big-endian the semantics we want are always "do
>>> nothing" so it's always OK to undef and redefine...
>>> That would save having a special case.
>>
>> Yes, please.
>
> It occurred to me that you could also have the unconditional
> #undefs outside the #ifdef HOST_WORDS_BIGENDIAN, but that
> is starting to stray outside of the "simple fix for 1.1"
> territory.
For 1.2 I would suggest to go even further and drop these SLIRP-specific
macros in favor of QEMU-wide available ones. static inline functions
would've avoided the problem in the first place.
Andreas
--
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg
Re: [Qemu-devel] [PATCH for-1.1? v2] slirp: Avoid statements without effect on Big Endian host
On 28 May 2012 12:47, Jan Kiszka wrote:
> On 2012-05-28 00:10, Peter Maydell wrote:
>> On 27 May 2012 17:42, Andreas Färber wrote:
>>> +# if defined(__APPLE__)
>>> +# undef NTOHL
>>> +# undef NTOHS
>>> +# undef HTONL
>>> +# undef HTONS
>>> +# define NTOHL(d) do { } while (0)
>>> +# define NTOHS(d) do { } while (0)
>>> +# define HTONL(d) do { } while (0)
>>> +# define HTONS(d) do { } while (0)
>>> +# else
>>
>> We could just use this for everything, not just if __APPLE__,
>> right? For big-endian the semantics we want are always "do
>> nothing" so it's always OK to undef and redefine...
>> That would save having a special case.
>
> Yes, please.
It occurred to me that you could also have the unconditional
#undefs outside the #ifdef HOST_WORDS_BIGENDIAN, but that
is starting to stray outside of the "simple fix for 1.1"
territory.
-- PMM
Re: [Qemu-devel] [PATCH for-1.1? v2] slirp: Avoid statements without effect on Big Endian host
On 2012-05-28 00:10, Peter Maydell wrote:
> On 27 May 2012 17:42, Andreas Färber wrote:
>> +# if defined(__APPLE__)
>> +# undef NTOHL
>> +# undef NTOHS
>> +# undef HTONL
>> +# undef HTONS
>> +# define NTOHL(d) do { } while (0)
>> +# define NTOHS(d) do { } while (0)
>> +# define HTONL(d) do { } while (0)
>> +# define HTONS(d) do { } while (0)
>> +# else
>
> We could just use this for everything, not just if __APPLE__,
> right? For big-endian the semantics we want are always "do
> nothing" so it's always OK to undef and redefine...
> That would save having a special case.
Yes, please.
Jan
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Re: [Qemu-devel] [PATCH for-1.1? v2] slirp: Avoid statements without effect on Big Endian host
On 27 May 2012 17:42, Andreas Färber wrote:
> +# if defined(__APPLE__)
> +# undef NTOHL
> +# undef NTOHS
> +# undef HTONL
> +# undef HTONS
> +# define NTOHL(d) do { } while (0)
> +# define NTOHS(d) do { } while (0)
> +# define HTONL(d) do { } while (0)
> +# define HTONS(d) do { } while (0)
> +# else
We could just use this for everything, not just if __APPLE__,
right? For big-endian the semantics we want are always "do
nothing" so it's always OK to undef and redefine...
That would save having a special case.
-- PMM
