DSP is simply a compute architecture that focuses on mutliply and accumulate operations on particular numerical formats, often either fixed point q15/q31 type values or floats f16/f32.

The basic operation that a NN needs accelerating is... go figure multiply and accumulate with the added activation function.

See for example how the Intel NPU is structured here: https://intel.github.io/intel-npu-acceleration-library/npu.h...