[FFmpeg-devel] [PATCH] Make HAVE_FAST_UNALIGNED allow unaligned memory accesses

[Måns Rullgård]

Michael Niedermayer <michaelni at gmx.at> writes:

> On Tue, Jul 15, 2008 at 08:16:21PM +0100, Mans Rullgard wrote:
>> If HAVE_FAST_UNALIGNED is defined, potentially unaligned data is
>> accessed through normal pointers.  Otherwise, compiler-specific
>> code is used to perform unaligned accesses, falling back to
>> byte-wise access if no compiler support is available.
>> ---
>>  libavutil/intreadwrite.h |  130 +++++++++++++++++++++++++++------------------
>>  1 files changed, 78 insertions(+), 52 deletions(-)
>
> [...]
>
>> @@ -37,7 +39,19 @@ struct unaligned_16 { uint16_t l; } __attribute__((packed));
>>  #define AV_WN32(a, b) (((struct unaligned_32 *) (a))->l) = (b)
>>  #define AV_WN64(a, b) (((struct unaligned_64 *) (a))->l) = (b)
>>  
>> +#elif defined(__DECC)
>> +
>> +#define AV_RN16(a) (*((const __unaligned uint16_t*)(a)))
>> +#define AV_RN32(a) (*((const __unaligned uint32_t*)(a)))
>> +#define AV_RN64(a) (*((const __unaligned uint64_t*)(a)))
>> +
>> +#define AV_WN16(a, b) *((__unaligned uint16_t*)(a)) = (b)
>> +#define AV_WN32(a, b) *((__unaligned uint32_t*)(a)) = (b)
>> +#define AV_WN64(a, b) *((__unaligned uint64_t*)(a)) = (b)
>
> This change is ok, as a seperate commit (note ive edit it, the removial
> of #else on its own would break the code).

Done.

-- 
M?ns Rullg?rd
mans at mansr.com