[U-Boot] Strange arm9 behaviour reading long(s) not aligned to 4 bytes boundary

[U-Boot] Strange arm9 behaviour reading long(s) not aligned to 4 bytes boundary

[dibacco at libero.it]

Hi,

I have something like this on a 32 bit little endian arm9 board (SAM9 
L9260):

char buffer[] = { 0, 1, 2, 3, 4, 5, 6, 7 };

long A = * ( (long*) 
buffer );
long B = * ( (long*) (buffer + 2) );

printf("A: %08x  B: %08x", A, 
B);

I would expect that A = 0x03020100 and B = 0x05040302
instead I get the 
right value for A but  B is 0x01000302 or something like this but anyway not 
what I expect. 
Is there something wrong on the board? It seems that only 4 
bytes aligned long are read correctly.

Thank you in advance,
Antonio.


 

[U-Boot] Strange arm9 behaviour reading long(s) not aligned to 4 bytes boundary

[Måns Rullgård]

"dibacco at libero.it" <dibacco@libero.it> writes:

> Hi,
>
> I have something like this on a 32 bit little endian arm9 board (SAM9 
> L9260):
>
> char buffer[] = { 0, 1, 2, 3, 4, 5, 6, 7 };
>
> long A = * ( (long*) 
> buffer );
> long B = * ( (long*) (buffer + 2) );
>
> printf("A: %08x  B: %08x", A, 
> B);
>
> I would expect that A = 0x03020100 and B = 0x05040302
> instead I get the 
> right value for A but  B is 0x01000302 or something like this but anyway not 
> what I expect. 
> Is there something wrong on the board? It seems that only 4 
> bytes aligned long are read correctly.

ARM9 does not support unaligned load/store.  Yours is apparently
configured in the round-and-rotate mode.

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