7. General architectural features

Generally speaking, the latest DSPs are equipped with :

• internal, and sometimes external, Harvard-type architecture: one memory bank for data, the other for programs;

• pipeline operation.

In what follows, we'll review the principles and implications of these features. When we take a close look at the architecture of a DSP, we find characteristics that we attribute to reduced-instruction-set machines, or RISCs, i.e. :

• each sub-cycle of a pipelined operation must see an instruction completed, and this condition imposes a "single word" format for instructions;

• because of this instruction structure, decoding is simplified and a wired, non-microcoded sequencer is possible; the space occupied by control...