In this section we will see how we have proceeded to arrive to an assembly program for the ADSP-2181 that achieves what we have described in the previous pages. It won't be a mere translation from mathematical operations to a correspondent code, since besides the correct achievement of the required function there are more parameters involved. In the approach to the programming, we have to consider all the aspects that contribute, in different ways, to the whole quality of a software product. In this sense the following chart, due to N.E. Fenton, appears clarifing and exhaustive:

Figure 3:           Scheme for the evaluation of software quality.

This scheme was introduced in the sphere of software measurement to define a route to follow to evaluate or measure the quality of a software product. It shows some aspects that have been considered during the definition of the code. For example, besides trustfulness, we were careful of efficiency, usableness and modularity. The last aspect also appears in the following scheme that shows the general structure of the whole assembly program:

Figure 4:           Structure of the whole program.

We present now the block diagram of the main loop, to have a little more detailed sight of the body of the program. We won't give here details about the data structure we have used: to have information and details of the assembly code you can directly contact Blue Wind.

Figure 5:           Main program flow chart.

We just make some notes about the contents of the flow chart:GOBACK is a status variable used to distinguish two different sub-cycles due to the communication between the Codec and the DSP; the variable INDICE is used as a pointer to the position of the last sample received; finally POLYPH is the routine relative to the first part of the elaboration that, as we can see comparing figures 1 and 5, could be seen as composed of three blocks.

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