FFT IP CORE: XK_INDEX???

When I use the xfft2.0 core to simulate a 1024_point FFT by the ModelSim. Why does the FFT's behavioral simulation fail with block RAM address errors, # **Warning:Undefined input WEA. Setting output DOUTA to X # Time: 22600 ps Iteration: 2 Instance:

/topo/xlxi_1/xlxi_1/u0/arch_b/xfft_inst/dpm0/dpm_inst # ** Warning: Invalid address ADDRA : UUUU1010. Entire memory contents will be set to

'X'. # Time: 22600 ps Iteration: 2 Instance:

/topo/xlxi_1/xlxi_1/u0/arch_b/xfft_inst/dpm0/dpm_inst # ** Warning: Undefined input ADDRB. Setting output DOUTB to X # Time: 22600 ps Iteration: 2 Instance:

/topo/xlxi_1/xlxi_1/u0/arch_b/xfft_inst/dpm0/dpm_inst

From the wave, I find the start,rfd,busy,edone,done and the dv are the same as the datesheet

shown, but the xk_index is wrong, it just shows sixteen numbbers: 0,64, 128,192,256....,960,

why? where are the other values? Who has ever met this problem?I would appreciate your help

very much.