Caching of external memory

Hi.

We are working on a Virtex4 FX12 PowerPC system. The code below is stored in BRAM and so are the stack and heap.

Using cache on the external memory crashes the program after approx.

The program below clears the memory, then it checks half the memoryspace for zeros and writes the addresses of the zeros in the other half.

Any sugestions why caching of external memory doesn't work?

/////// CODE ////////////////////

#define CHECK_BASE_ADDR XPAR_DDR_SDRAM_32MX16_MEM0_BASEADDR #define CHECK_HIGH_ADDR (WRITE_BASE_ADDR-1) #define WRITE_BASE_ADDR (XPAR_DDR_SDRAM_32MX16_MEM0_BASEADDR+0x02000000) #define WRITE_HIGH_ADDR XPAR_DDR_SDRAM_32MX16_MEM0_HIGHADDR

Xuint32* CheckPtr = (Xuint32*)CHECK_BASE_ADDR; Xuint32* WritePtr = (Xuint32*)WRITE_BASE_ADDR;

int main (void) {

ClearMemory();//write zeros at all memory locations

XCache_EnableICache(0x00000001); XCache_EnableDCache(0x80000001);

while(1) { if(*CheckPtr==0) { *WritePtr = CheckPtr; if(++WritePtr > WRITE_HIGH_ADDR) WritePtr = WRITE_BASE_ADDR; } if(++CheckPtr > CHECK_HIGH_ADDR) CheckPtr = CHECK_BASE_ADDR; } }