Could not read 8 bit data from custom ram

Hi again,

I just modified code vhdl ( add 1 when calculating address to read ram_content)

if(read='1') then
        --- readdata <= RAM_CONTENT(conv_integer(address));
	readdata <= RAM_CONTENT(conv_integer(address)+1); -- add 1
end if;

then i ran this code in NIOS:

# include <stdio.h>
# include <io.h>
# include "system.h"
int main()
{
  int i;
  printf("Hello from Nios II!\n");
  printf("refill content of RAM\n");
  for(i=0; i<16; i++)
    IOWR_8DIRECT(PIXELS_BUFFER_0_BASE, i, i);
  
  printf("check wrote content\n");
  for(i=0; i<16; i++)
  {
    char x = IORD_8DIRECT(PIXELS_BUFFER_0_BASE, i);
    printf("Addr: %i\t%i\t", i, x);
    if(x!=i) printf(" <= ERROR\n");
    else printf("\n");
  }
  
  printf(" check again\n");
  for(i=0; i<16; i++)
  {
    char x = IORD_8DIRECT(PIXELS_BUFFER_0_BASE, i);
    printf("Addr: %i\t%i\t", i, x);
    if(x!=i) printf(" <= ERROR\n");
    else printf("\n");
  }
  
  printf("refill content but with new data\n");
  for(i=0; i<16; i++)
    IOWR_8DIRECT(PIXELS_BUFFER_0_BASE, i, 15-i); // add 0: 15 , add 1:14 ...
    
  printf("check wrote content\n");
    for(i=0; i<16; i++)
      {
        char x = IORD_8DIRECT(PIXELS_BUFFER_0_BASE, i);
        printf("Addr: %i\t%i\t", i, x);
        if(x!=15-i) printf(" <= ERROR\n");
        else printf("\n");
      }
      
  printf("check again\n");
    for(i=0; i<16; i++)
      {
        char x = IORD_8DIRECT(PIXELS_BUFFER_0_BASE, i);
        printf("Addr: %i\t%i\t", i, x);
        if(x!=15-i) printf(" <= ERROR\n");
        else printf("\n");
      }
  return 0;
}

I received new result, something still wrong, but in special case, as u see below:

Hello from Nios II!
refill content of RAM
check wrote content
Addr: 0	15	 <= ERROR
Addr: 1	1	
Addr: 2	2	
Addr: 3	3	
Addr: 4	4	
Addr: 5	5	
Addr: 6	6	
Addr: 7	7	
Addr: 8	8	
Addr: 9	9	
Addr: 10	10	
Addr: 11	11	
Addr: 12	12	
Addr: 13	13	
Addr: 14	14	
Addr: 15	15
	
check again
Addr: 0	0	
Addr: 1	1	
Addr: 2	2	
Addr: 3	3	
Addr: 4	4	
Addr: 5	5	
Addr: 6	6	
Addr: 7	7	
Addr: 8	8	
Addr: 9	9	
Addr: 10	10	
Addr: 11	11	
Addr: 12	12	
Addr: 13	13	
Addr: 14	14	
Addr: 15	15
	
refill content but with new data
check wrote content
Addr: 0	0	 <= ERROR
Addr: 1	14	
Addr: 2	13	
Addr: 3	12	
Addr: 4	11	
Addr: 5	10	
Addr: 6	9	
Addr: 7	8	
Addr: 8	7	
Addr: 9	6	
Addr: 10	5	
Addr: 11	4	
Addr: 12	3	
Addr: 13	2	
Addr: 14	1	
Addr: 15	0
	
check again
Addr: 0	15	
Addr: 1	14	
Addr: 2	13	
Addr: 3	12	
Addr: 4	11	
Addr: 5	10	
Addr: 6	9	
Addr: 7	8	
Addr: 8	7	
Addr: 9	6	
Addr: 10	5	
Addr: 11	4	
Addr: 12	3	
Addr: 13	2	
Addr: 14	1	
Addr: 15	0

I still dont known what happened. When i rewrite data at offset 0, then first read bring me wrong number, but in the 2nd, it became right number. hix, could anybody explain that for me? Thanks!