File of " Hybrid Dataflow / von - Neumann Architectures " FAHIMEH YAZDANPANAH

Execution Model SIGMA-1 is a dynamic dataflow machine having ability of vector processing in control flow manner. SIGMA-1 uses structure-flow processing scheme for handling data structures in dataflow architecture. In this scheme, the arrival of a data structure unrolls the control structure which processes the data structure itself using a high-level structure. A structure-flow is defined as a set of element data flowing in the form of packets with two kinds of identifiers. The first, is the identifier of the whole structure and the second is the identifier that indicates the logical position of the element data. To gain high performance in numerical programs, parallelism in a structure must be fully utilized, and a unified computing scheme within total structure level parallel processing and element-wise scalar level parallel processing is necessary. The other structure handling methods [1]–[3], [8], [10], [21], such as I-structure, are based on element-wise access to the structure. When element-wise structure access is used in a dataflow computation, structure access is processed similar in vonNeumann processors except that the instructions are triggered by the arrival of input data. However, there are several problems in element-wise access to a structure caused by increasing the number of instructions and packets and the amount of the required memory. On the other hand, structure-flow is a method for accessing a whole structure in the dataflow manner. Elements in a structure are placed in matching memories and buffers. Since the cost of matching memories and buffers is