1989 Reports

The IIc Parallel Language and Its Implementation on Dado2

Mills, Russell C.

llc is an extension of C that has been implemented on the massively parallel Dado2 tree-structured MIMD multicomputer. In an llc program, a single controlling processor invokes operations in parallel in subsets of a set of attached processors, which themselves can invoke parallel operations in remaining processors. Language features include distributed storage (objects with one element per processor), the ability to pass parallel values as function arguments and to return them from functions, and built-in and user-defined reduction operators. The paper first describes the synchronous model of hierarchically parallel computations used by llc. It next describes the syntax of the llc language and its semantics in detail. It then describes the Dado architecture and the implementation of llc on Dado2. A summary of the strengths of llc follows. Finally, several examples of llc programs help to clarify the important features of the language.