News and New Products

C synthesis tool features larger capacity

By Michael Santarini, Senior Editor -- EDN, 6/13/2006

Mentor Graphics has introduced a higher capacity version of its Catapult C ANSI-C++-based synthesis tool that designers can now use to build a prototype of a full DSP-based subsystem. Mentor in 2004 introduced the first version of its Catapult C tool to help IC architects design DSP-centric SOC (system-on-chip) blocks at an algorithmic level. Unlike other ESL (electronic-system-level)-design tools that run on specialized languages, the Catapult C tool uses ANSI-C++ as an input and generates RTL (register-transfer-level) design for hardware design, as well as a SystemC transaction-level model for simulation. “The source description is strictly functional,” says Shawn McCloud, Catapult’s product-marketing manager. The source description requires no hardware detail, he claims. Instead, the synthesis tool inserts the hardware detail. “This separation of technological intent from functional specification is a key driver of the technology,” says McCloud.

Since its formal introduction in 2004, Catapult C has seen the highest adoption rate of any Mentor tool, he claims growing 145% in 2005 over 2004. It has seen its highest adoption in Japan. That version of the tool suited only block-level synthesis. The new version of the tool, Catapult SL (system level) adds support for hierarchy and other features that allow architects to use the tool to design a subsystem prototype. The company added a new hierarchical engine that increases the tool’s capacity and manages complexity. “Like any other tool in this area, the older version of Catapult synthesized individual blocks. Users would then have to stitch the blocks together,” says McCloud. Catapult SL can now do multilevel subsystems.

McCloud says that customers have used the SL tool to design 3.5 million-gate subsystems. However, the company believes the tool can handle 10 million or more gates. The algorithm performs a top-level analysis, propagates all that information to the lower level blocks, and then independently optimizes each block. The tool can reorganize sequential functions to make them run concurrently. A new channel-synthesis feature optimizes the interfaces between the blocks in the subsystem. “It automatically does the analysis of the data rates between the blocks and then automatically inserts the appropriate channel size, FIFO depth, or memory depth to prevent the system from locking when you pipeline the subsystem,” McCloud says. Thus, channel synthesis coordinates the communications between the blocks.

The tool can also automatically implement carry-save-adder trees in one step and can generate a SystemC TLM (transaction-level model) that you can feed into Mentor’s Questa multilanguage simulator. That tool can generate VCD (value-change-dump) files that you can feed into third-party power tools and then return to Catapult SL to analyze power consumption.

With the introduction of Catapult SL, Mentor has changed the naming convention of its entire Catapult lineup. The original version of Catapult C++ is now Catapult BL (block level) and costs $140,000 for an annual license. The company also offers the ANSI C++ Catapult LB (library builder). Catapult SL costs $350,000 for an annual subscription.