A language for machine organization design (computer hardware description languages)
Gregory Frederick Maxey · 1984
There has been considerable research directed toward the use of high-level computer hardware description languages (CHDLs) in the automated design of digital hardware, but attempts to produce efficient hardware designs in this way have had litle success. This is primarily because previous high-level CHDLs could not represent the design of a large digital system in a way that could be related directly to a low-level hardware realization. ALAMODE is a high-level CHDL for architectural description of computers and other digital systems. A system description in ALAMODE is written at the architectural level, but it contains the details of the machine organization as well as the features of the external architecture. The structural descriptive style of ALAMODE provides a direct relationship between the description of a machine and its hardware design. The description of a digital system in ALAMODE consists of one or more module descriptions. A module description is divided into the ABSTRACTIONS, STRUCTURE, and CONTROL sections. The ABSTRACTIONS section establishes the module's primary data representations and data transformation operations. The STRUCTURE section provides a complete description of the module's structural elements, including both data storage and data transformation elements, and the data paths that connect them into the structure. Described modules are themselves instantiated as structural elements within other modules, and communicate via data paths connected to their input and output ports. Finally, the CONTROL section describes the enabling of actions in the structure, in terms of a self-timed finite state machine. ALMODE's general model supports a very wide range of system design styles. In addition, the definitions in the ABSTRACTIONS section and the creation of user-defined structural element types in the STRUCTURE section give the language the flexibility to permit the use of the ideal primitives for each design. As a design medium, ALAMODE promotes system designs that are well organized and free of synchronization failure and other low-level errors.