Newbie: arm-elf-gcc generated asm question

Ken Barlow wrote:
>>>Is there a way of forcing all alignment onto four byte boundaries?  I've
>>>looked through the GCC and LD docs and can find switches for other
>>>targets, but not the ARM.
>>
>>Compiler does this automatically.  If you, say, have the structure
>>
>>struct {
>>     uint8_t   one;
>>     uint32_t  two;
>>} foo;
>>
>>then foo.two will always be word aligned.
>>
>>What are your trying to do?  If you would post a snippet of your data
>>structure it might be easier to help.
>>
> 
> 
> Hi again,
> 
> The structure is like this:
> 
> struct {
>     uint8 aByte;
>     uint8 aByteArray[ 64 ];
> } foo;
> 
> Hence my problem - the aByteArray is used as a generic buffer that can hold
> anything.  I was putting 32bit words into it, and as a byte array  there is
> no way of the compiler knowing that I wanted it 32bit aligned - a bit silly
> now I come to look at it but sometimes it takes somebody else to point out
> you are doing something daft ;-)
> 


I think you can force gcc to align the buffer using:

struct {
     uint8 aByte;
     uint8 aByteArray[ 64 ] __attribute__ ((aligned (4)));
} foo;

(untested)


--
Arne