C5517 SDRAM Mapping

I've got a C5517 development board with 8MB of SDRAM. I've tested it using the CSL example, and that works fine, but I'd like to set it up so that the user can just assign an array to the external ram and then read and write to it normally. As such, I've set up my .cmd file as follows:

-stack    0x2000                /* PRIMARY STACK SIZE    */
-sysstack 0x1000                /* SECONDARY STACK SIZE  */
-heap     0x6400                /* HEAP AREA SIZE        */  

MEMORY
{
  PAGE 0:
    VEC(RWX)	  : origin = 0000100h length = 000200h
    DATA0(RWX)    : origin = 0000300h length = 05D00h 
    DATA1(RWX)    : origin = 0006000h length = 0A000h 
    SARAM0(RX)    : origin = 0010000h length = 038000h            
    SARAM1(RW)    : origin = 0048000h length = 002000h  
    SARAM2(RW)    : origin = 004A000h length = 002000h  
    SARAM3(RW)    : origin = 004C000h length = 002000h
    SDRAM(RW)     : origin = 0050000h length = 800000h
    
}

SECTIONS
{
  vectors       : > VEC ALIGN = 256
  .text         : > SARAM0 ALIGN = 4
  .data         : > SARAM0 
  .cinit        : > SARAM0 
  .switch       : > SARAM0
  .stack        : > DATA1 
  .sysstack     : > DATA1 
  .bss          : > SARAM0 , fill =0 
  .sysmem       : > DATA1
  .const        : > SARAM0
  .cio	        : > SARAM0
  .extmem       : > SDRAM
  USB_buffer1   : > SARAM1
  USB_buffer2   : > SARAM2 
  USB_buffer3   : > SARAM3 , fill =0   
  
  GROUP: align(32)
  {
	.const:twiddle32
       	.const:twiddle
	audio_buffers
	fft_buf
	
  } > DATA0
}

then, in my C++ program, I have:

#define RAM_BUFFER_LENGTH 400

#pragma DATA_SECTION(".extmem")
int test_array[RAM_BUFFER_LENGTH];

void testRam()
{
    int status;
   

    
    //Initialize OLED module for status display
    disp.oledInit();
    disp.clear();
    disp.flip();
    disp.setline(1);
    SDRAM.init();
    
  
    for (int index = 0; index < RAM_BUFFER_LENGTH; index++)
    {
        test_array[index] = 17;
    }
    
//    for (int index = 0; index < RAM_BUFFER_LENGTH; index++)
    {
      disp.clear();  
      disp.setline(0);
      disp.print((long) test_array[0]);
      disp.setline(1);
      disp.print((long) test_array);      
    }
    
}

This should print an address in the extmem memory space to the oled display that I have. The value is correct, but the address in DATA0 no matter what I put in my pragma, despite the fact that it compiles -- which it does even if I put a garbage address in it.

Note, that SDRAM.init(); is a wrapper for the CSL EMIF setup function, I get the same behavior without it, but I expect to need to initialize the RAM registers, which this does.

I susupect I'm just using the pragma wrong, but this looks like it matches the compiler user's guide.