SDRAM and Audio problem

I want to write some data in SDRAM with a FOR cicle and connect the audio codec MIC (in) to audio codec spk(out), the audio code segment is ok, the problem is when I add the write sdram function because the program stops, I saw (before running program) that initially some data (probably code) is in sdram memory and I think maybe the write sdram function is changing the program code. Here the question is: Why program data in SDRAM if I configured in SOPC builder reset and exception vector in SRAM ??? What I can do to put the code program on SRAM and not SDRAM.

Here the code :

# include "sdram_to_audio.h"

long i;

alt_u16 cont=0;

void write_sdram()

{

alt_u16 *buffer = (alt_u16 *) 0x00800000; // base addr SDRAM

for (i=0; i<=127; i++){

buffer[i]=cont;

cont++;

}

}

int main()

{

volatile int * audio_ptr = (int *) 0x10003040; // audio port

long audiobuf[128];

/* used for audio record/playback */

int fifospace;//, leftdata, rightdata;

int buffer_index = 0;

write_sdram();

while (1)

{

fifospace = *(audio_ptr+1); // read the audio port fifospace register

if ((fifospace & 0x000000FF) > 96)

{

audiobuf[buffer_index] = *(audio_ptr + 3); // read right channel only

buffer_index++;

}

fifospace = *(audio_ptr+1); // read the audio port fifospace register

if (((fifospace & 0x00ff0000)>>16) > 96) {

buffer_index--;

//Write to both channels

*(audio_ptr + 2) = audiobuf[buffer_index];

*(audio_ptr + 3) = audiobuf[buffer_index];

}

}

}