BDTI’s DSP Insider Archives
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This month:
Embedded C Extensions Move ForwardLast month the ISO approved the final technical ballot for Embedded C, an extension to the C programming language that will ease signal-processing software development. After an additional round of editing, the ISO is expected to publish the Embedded C specification as a “technical report.” An ISO technical report is similar to a standard, but carries somewhat less authority. Embedded C extends the C programming language with support for fractional arithmetic, multiple address spaces, and I/O registers. The development of Embedded C was influenced by the needs of signal-processing software and by the hardware features of DSP processors. The support for fractional arithmetic and multiple address spaces will be particularly useful for signal-processing applications. Fixed-point signal-processing algorithm software often uses fractional data, where numbers range from -1 to +1. Because C does not directly support fractional data types, implementing signal-processing algorithms in standard C can be awkward and error-prone. Embedded C addresses this problem by adding “fract” and “accum” data types. The fract data type supports basic fractional operations, and the accum data type supports the special-purpose “accumulator” registers available on most DSP processors. Embedded C also adds support for multiple memory spaces, a common feature of DSP processors. For example, DSP processors often contain multiple data memory banks. Obtaining maximum performance from a signal-processing application typically requires careful placement of data in the appropriate memory spaces. In light of this need, Embedded C enables programmers to specify which memory space should be used for each item of data. Numerous processor and compiler vendors have offered proprietary variants of C with these and related features for many years. However, these proprietary solutions offered limited portability. In contrast, applications created in Embedded C will become portable across a wide range of processors as compiler developers adopt Embedded C. This portability has the potential to greatly improve code reusability and to give system designers more flexibility in choosing a processor. Just as importantly, Embedded C will promote a consistent programming style for signal-processing applications. Today’s proprietary solutions take widely varying approaches to supporting signal-processing applications. Consequently, programmers must learn a new programming style whenever they switch tools. In contrast, programmers will be able to move between Embedded C-based tools without having to learn a new syntax.
The Embedded C technical report is available online at
http://std.dkuug.dk/JTC1/SC22/WG14/.
Telairity Introduces Vector DSP CoreLicensing upstart Telairity introduced its high-performance DSP core, the TVP400, at last month’s HotChips conference. On the surface, the TVP400 resembles competing high-performance DSP cores. For example, the TVP400 is projected to achieve a worst-case clock speed of 420 MHz in a 0.13-micron process, which is comparable to the 300–400 MHz clock speeds achieved by competing DSP cores. The TVP400 also delivers a level of parallelism similar to that of its competitors. For example, the TVP400 is capable of completing four 16-bit multiply-accumulate (MAC) operations per cycle. Most competing high-performance DSP cores, such as the ZSP600, are also capable of performing four 16-bit MACs per cycle. However, closer inspection reveals that the TVP400 uses an unusual form of parallelism. Although the TVP400 contains four independent “vector units,” in each cycle it generally issues only one instruction to one of the four vector units. To keep the vector units busy, the TVP400 uses vector instructions that specify repetitive sequences of operations. For example, a single vector instruction might direct a vector unit to add eight successive pairs of operands from eight pairs of registers; such instructions operate on one pair of operands per cycle. These vector instructions allow the TVP400 to initiate operations in one vector unit and then launch other operations in other vector units while the first vector unit continues to operate. Each vector unit also contains a vector load/store unit. Like the arithmetic units, these vector load/store units can be configured to perform repetitive sequences of operations. Each vector load/store unit can perform two 16-bit loads and one 16-bit store per cycle, for a total of twelve independent data transfers per cycle. The ability to access twelve memory locations per cycle is highly unusual. Competing DSP cores can access only two independent memory locations per cycle. As a result, competing DSP cores typically achieve high levels of parallelism only when data can be loaded in chunks of contiguous words. In contrast, the TVP400 can operate efficiently on scattered data.
Vector processors have a long history in the world of supercomputers,
so it is not surprising that Howard Sachs, Telairity’s president, once
worked at Cray Laboratories. But vector processors are rare in the
world of embedded computing. Telairity may face reluctance among
prospective users due to the unfamiliar approach used in the TVP400.
While signal processing algorithm designers typically work with
vectors and matrices as their most natural data types, DSP software
developers generally are not familiar with the concepts of vector
processors.
BDTI Case Study
This Month: Polishing Technical Marketing PresentationsThe quality of the marketing presentation and press briefing materials for a new technology product or service is critical to convincing prospective customers, partners, editors, and investors that the product is attractive and viable. Presentations should combine clear, convincing technical information with a compelling marketing message—a difficult combination to achieve. And even accurate, convincing presentations can run into trouble if the presenter isn’t prepared for tough questions. The best way to ensure that a presentation is accurate and effective is to test it with a knowledgeable, critical, and responsive audience. It is far better to uncover errors with a test audience than during a critical customer or press presentation. A test audience can also help ensure that the content is clear, relevant, and appropriate for the intended audience. Just as important, a test audience can help presenters gauge the appeal and impact of their pitch. After all, superb technical content serves no purpose if the audience loses interest a few minutes into the presentation. Through its “Sounding Board” service, BDTI offer the expertise of its analysts as a test audience for marketing presentations and press briefings on new signal-processing-related products and technology. BDTI’s analysts have worked as design engineers and have spent years tracking the DSP industry—and listening to hundreds of new-product pitches. This experience makes them a shrewd and skeptical audience with a unique combination of technical expertise and industry savvy. The Sounding Board service provides specific, detailed suggestions for achieving technical accuracy and clarity and focusing the marketing message for the target audience. In addition, the Sounding Board service often identifies product advantages that the presenter had overlooked. In one Sounding Board engagement, a reconfigurable-hardware vendor employed BDTI’s services to refine a key technology positioning presentation. After a careful review of the draft presentation, BDTI’s analysts made detailed recommendations showing the vendor how to tie its products’ features to concrete advantages for end users. BDTI also pointed out major benefits of the technology that the vendor had underplayed. The vendor used these suggestions to create a more effective presentation—one that engaged the audience and delivered a clear and convincing message.
Sounding Board sessions are available at BDTI’s offices, via
conference call, and via Web conference. To learn how BDTI can help
you improve your presentations, contact Jeremy Giddings
(giddings@BDTI.com) or visit
http://www.BDTI.com/products/services_sounding.html.
Impulse Response, by Jeff Bier
Watch Your BackThink you know who your competitors are? You’d better watch your back, because changes in end products are forcing processor vendors and equipment manufacturers to face unfamiliar new foes. Convergence is the key trend causing new rivalries to arise. One of the most obvious examples of convergence is the cell phone. Cell phones are acquiring the functionality of PDAs, digital still cameras, and digital audio players. (Next year they’ll probably incorporate can openers and vacuum cleaners.) This merging of capabilities is pitting processor vendors with long histories in the cell phone market—think Texas Instruments—against companies that built their success in other applications—Intel being a prime example. And more twists are coming. Handset developers are betting that integrating sophisticated 3D gaming into phones will provide differentiation and drive sales. Nokia has already announced its “N-Gage” gaming handset (which bears more resemblance to a Game Boy than a phone) and has purchased multiplayer gaming technology from Sega. This focus on 3D graphics is reconfiguring the competitive field. For example, Texas Instruments licensed 3D accelerators from Imagination Technologies Group earlier this year, a move clearly intended to enable TI to offer cell-phone chips with 3D graphics capabilities. And last month NVIDIA, a vendor of graphics chips for PCs and game consoles, announced it would acquire MediaQ, a developer of processors for handsets and PDAs. The significance of these moves is clear: Texas Instruments and NVIDIA are about to become competitors. Convergence is also creating new competitors in the world of consumer electronics. Game consoles, set-top boxes, personal video recorders, and DVD players are on a collision course. As these products merge, equipment manufacturers that have dominated particular product segments are coming under attack from unfamiliar directions. Similarly, the chip vendors who supply these equipment manufacturers are facing unsettling new competition.
Who will win these increasingly confusing contests? As convergence
creates ever more complex systems and chips, superiority in any
particular technology, such as wireless communications, is unlikely to
be the decisive factor. Rather, victory will belong to the companies
best able to quickly and effectively integrate the range of
technologies needed for the emerging “über-boxes.”
BDTI Updates Free Pocket GuideBDTI’s popular Pocket Guide to Processors for DSP has been updated for 2003. The new version includes key facts on over 40 processors—including both off-the-shelf-chips and licensable cores—from 13 leading vendors.
To view the new Pocket Guide online, go to
http://www.BDTI.com/pocket/pocket.htm. Or to request a print copy,
register at http://www.BDTI.com/ecommerce/forms/addme.htm and check
the “Send me a Pocket Guide” box.
BDTI Updates Benchmark ScoresBDTI has updated and reorganized its BDTImark2000™ and BDTIsimMark2000™ scores. The updated scores are now grouped into two categories: “Packaged Processors” and “Licensable Cores.” Processors that fall into both categories now have separate scores shown for each category. For these scores, go to http://www.BDTI.com/bdtimark/BDTImark2000.htm.
The BDTIsimMark2000™ and BDTImark2000™ are summary measures of
DSP speed distilled from a suite of DSP benchmarks developed and
independently verified by BDTI.
BDTI Workshops at the 2003 Communications Design ConferenceWondering which processors are best for mobile multimedia applications? Need to know whether you should use an FPGA or a DSP in your communication system? Join BDTI for two workshops at CDC in San Jose, September 30 to October 2, and find out. BDTI’s CDC 2003 workshops are:
Top BDTI Provides Creative Solutions to Tough ChallengesDo you need to:
You will find more information on these and other BDTI products and
services at http://www.BDTI.com. Or contact Jeremy Giddings at
giddings@BDTI.com.
About BDTIBDTI is an independent source for digital signal processing technology analysis and optimized software development services. From rigorous technical analyses of processors for DSP, such as the Inside series of processor analyses, to highly regarded technology seminars, BDTI is the trusted independent source for reliable information on digital signal processing technology. As a software developer, BDTI is known for highly optimized implementations of signal processing algorithms and applications and for solutions to complex problems of integration, code size, and performance.
For more information, visit our Web site at http://www.BDTI.com.
The next issue of BDTI’s DSP Insider is coming in October. Previous issues of BDTI’s DSP Insider are archived on BDTI's Web site. Follow the link from http://www.BDTI.com/dspinsider.htm. If you have comments, suggestions, or other feedback about the DSP Insider, please send email to dspinsider@BDTI.com. BDTI’s DSP Insider is a free monthly electronic newsletter published by Berkeley Design Technology, Inc. If our newsletter was forwarded to you and you would like to receive it regularly, please register at http://www.BDTI.com/dspinsider.htm.
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