memory assignment on a ddr-sdram

Hello,

I have a C program which works but I would like to have a buffer stored on the ddr sdram. Thus, I used the function "__attribute__"

The problem is that I would like my buffer size to be 640*480.

unsigned int buffer_video [640*480] __attribute__ ((section (".ddr_sdram")));

When I do a 64*48 buffer, it works but for example, when doing a 90*50 buffer, I have the error :

Verifying 00010000 ( 0%)

Verifying 00013C2C (45%)

Verify failed between address 0x13C2C and 0x1827B

Leaving target processor paused

Does someone have an idea ?

Thanks,

Myriam