Santa Cruz, Calif. -- The high-level Register Description Language (RDL) is no longer available on an open-source basis, but an enhanced version called SystemRDL is being offered free by Denali Software Inc., that company will announce this week.
Denali last year introduced RDL as the input mechanism for its Blueprint product, which generates several "views" for control register design. These include synthesizable RTL for hardware design, SystemC or hardware verification language models for verification, C code for software and firmware development, and documentation ready for formatting. To promote RDL as an industry standard, Denali late last year formed the RDL Alliance along with Mentor Graphics, MIPS and Rambus.
RDL appeared as an open-source language on the SourceForge Web site this March, apparently without Denali's involvement. Documents at the site made it clear that RDL originated at Cisco Systems Inc. Denali earlier had said that RDL came from a large systems design house, but Denali still declines officially to name that developer.
With this week's announcement, however, RDL will be removed from SourceForge, and SystemRDL can be freely downloaded at www.systemrdl.org. "We want to make sure there's a single specification," said Sean Smith, chief verification architect at Denali. "We have been actively working with our customers and partners to enhance the language, and what we're publishing will represent a superset of what has previously been published."
CTO Mark Gogolewski said that Denali owns SystemRDL, along with the systems design "partner" that he cannot legally identify. It's not open-source, but anyone can obtain it through a simple click-through license, he said.
"We really aren't changing much except where it's hosted," said Smith. "Everyone in the world will still have access to it. In our view, we're opening it up even further."
But Smith acknowledged that Denali will retain control over evolution of the language until it can be brought before a standards body. That's a "short-term goal," he said. Smith said that Denali has talked to standards organizations including Spirit, Accellera and the IEEE, but has not yet decided which one to work with.
SystemRDL is used to describe the details of register structures and operations, allowing automatic generation of synthesizable register code, models and documentation. It's an object-oriented language whose base components are fields, registers, register files and address maps. Properties can be specified for each component. Specialized component objects include signals and enumerations.
The original RDL, Smith said, reflected the design practices of a single company. He said that Denali and its partners have added extensions and enhancements to bring it into broader use. As an example, he noted that the company that created RDL used positive active synchronous resets. SystemRDL adds support for other reset types that may be used by other companies.
While Denali hopes that SystemRDL will become an industry standard, Blueprint is currently the only commercial tool that uses it. But that doesn't mean other designers can't make use of the language, Smith said.
"A lot of people have internal tools to do this [specify registers]," Smith said. "Denali believes the world deserves a standard language for sharing this kind of interface specification. By opening the language, we are creating an opportunity for IP [intellectual property] reuse and IP interchange that did not exist before."
See related image