StReAm: Object-Oriented Programming of Stream Architectures using PAM-Blox
[appeared at Field-Programmable Logic (FPL) Conference, Villach, Austria, 
 Sept. 2000]

by Oskar Mencer, Heiko Hubert, Martin Morf, Michael J. Flynn


Simplifying the programming models is paramount to the success of 
reconfigurable computing. We apply the principles of object-oriented 
programming to the design of stream architectures for reconfigurable 
computing. The resulting tool, \textbf{StReAm}, is a domain specific 
compiler on top of the object-oriented module generation environment 
PAM-Blox. Combining module generation with a high-level programming 
tool in C++ gives the programmer the convenience to explore the flexibility 
of FPGAs on the arithmetic level and write the algorithms in the same 
language and environment.

Stream architectures consist of the pipelined dataflow graph mapped 
directly to hardware. Data streams through the implementation of the 
dataflow graph with only minimal control logic overhead. The main advantage 
of stream architectures is a clock-frequency equal to the data-rate leading 
to very low power consumption.

StReAm takes C++ expressions and converts them to a pipelined, scheduled 
stream architecture, including FIFO buffers for intermediate storage. The 
state of PAM-Blox hardware objects includes size and scheduling attributes 
of the object. The StReAm abstraction of PAM-Blox can handle combinational, 
fully pipelined, and sequential (iterative) arithmetic units.

We show a set of benchmarks from signal processing, encryption, image 
processing and 3D graphics in order to demonstrate the advantages of 
object-oriented programming of FPGAs.