Future image of soft-core CPU

Batch Synthesis for Multi-Processors

The automatic generation of the aforementioned CPU targeted a single CPU, but as the next step, we are envisioning batch synthesis of multiple processors as shown in Figure 2. Here, the processor is not limited to the CPU, but indicates hardware that performs sequence processing, including simple sequencers and DSPs.

 

Figure 2 Batch Synthesis of Multi-Processors with Distributed Functions from One System Description

 

The automatic CPU generation in Fig. 1 is given processing division (function distribution) and various constraints to support a larger system, and a processor with optimal cost performance is generated for each function. It comprehensively judges how many processors are optimal for realizing the given required specifications, distributes the functions, and builds the optimal processors to execute the divided functions. If this is achieved, system design will become much easier.

 

System configuration when batch synthesis becomes common

 

Figure 3 shows a proposed configuration for a multiprocessor system. The same number of processors as the number of software layers (three layers in this case) are configured to share the processing of each layer. Since a processor is built for each necessary process, it is possible to make the processor completely different even if it is the same layer. Conversely, if performance improvement by parallelization is not required, one processor can have multiple functions. Is possible. In addition, the main bus and I/O bus have a crossbar configuration, and the image is of a configuration in which simultaneous access is possible as long as the access destinations of the processors with master rights on each bus do not conflict. Although the condition is that the FPGA resources allow it, I think you can understand that it is possible to design the system according to the user's wishes. However, doing all this manually would require a huge amount of man-hours, so tool support is essential.

Coming this far seems like a "dream story", but technological progress has overcome many obstacles, so I expect that the time will come when it will no longer be a "picture of rice cake".

 

Figure 3 Hierarchical Multiprocessor System Configuration Proposed by Distributing Functions

 

in conclusion

By making effective use of the flexibility of FPGA, it is possible to design the system as desired by the user. Recently, there is a strong tendency to purchase finished products and build systems without even designing them, from the design method of combining commercially available devices and realizing missing functions with FPGAs, but if this continues, the technology will be hollow. I often hear that people are afraid that they will become unable to make anything in the future.

Stopping the model that pursues only the early introduction of cheap products to the market, remembering the beginning of microcomputers that assembled parts (functions) from scratch, and returning to the origin of design where the thoughts of designers can be seen Is it not possible?

"A user-oriented SoC (System On Chip) can be realized from a single minimum order." We believe that FPGA with CPU will be one of the solutions, and we would like to continue working on it.

If you have time, I would appreciate it if you could read the series again and give me your opinion. Thank you for reading.