Multiplier : 2 Buses
Notes:
The bus structure of the C54x family is very flexible and works to optimize computations and increase performance. Let’s examine the way this structure is useful.
The multiplier is a fairly sophisticated device. We see in the upper left-hand corner, that there is a C bus and a D bus. This a unique feature to the C54x family, having two data buses.
If we consider a traditional algorithm such as a sum of products, we will iterate on multiplies and add them up in the accumulator. For each iteration the multiply operation can fetch both operands, one on D and one on C, feed them into the multiplier, and add them to the accumulator. The dual fetches, the multiply, and the add constitute a single cycle operation.
In certain situations, we can also use the program fetch instruction bus, as one of the operands into the multiplier.
These characteristics of the bus structure enable the designer to extract excellent performance using a C54x device.