Failure to compile WS1 LAB3

Hello all…

I am trying to work through WS1 LAB3 but the project fails to compile. The first error is…

In file included from msgdma/descriptor_regs.h:35:0,
from fft.c:43:
fft.c: In function ‘fft_main’:
fft.c:57:20: error: ‘FFT_SUB_DATA_BASE’ undeclared (first use in this function)

So far, I have been unable to find where that should be defined. Any help would be appreciated.