Game Development Reference
In-Depth Information
Another VLIW processor, the Philips TriMedia processors, can execute up to
five instructions per cycle. Besides the main CPU, there are other peripherals
which can take the load from the main CPU for particular computations. Another
advantage of this processor is the price, as well as the interfacing capabilities
(PCI bus, serial link, video input/output, MPEG encoding/decoding, etc.) and the
programming environment. In our application, we use TriMedia video capture
boards, with TM1300 processors. A detailed description of the testbed will be
given in the next subsection. Trimedia processors are media processors, which
have wider data paths, wider registers, and more flexible memory interfaces than
the regular DSPs. They can use data paths and register files to support SIMD
(single instruction multiple data) types of operations, which is very useful when
dealing with different real-time data inputs with varying dynamic range demands.
The Sharc ADSP 21160M is a SIMD processor that can be used for low-power,
image/video-processing applications, but its performance is below the others.
General purpose processors' (GPP) high power consumption and large size are
the main disadvantages for portable image/video-processing applications. An-
other important factor is cost. For cost sensitive applications, DSP devices are
significantly less expensive than GPPs. Code generation and debugging tools
have a major impact on the efficiency of the development effort. Unlike GPP
tools, some DSP development tools implicitly support the debugging of multipro-
cessor systems and provide unique data visualization tools.
In general, DSPs, unlike GPPs, are generally optimized for high throughput, data
streaming applications. Some of the key features that support this include
multiple bus architectures, multiple execution units that function in parallel,
multiple data and instruction memories (both internal and external), multiple
DMA channels for high speed data movement without processor involvement,
special addressing modes, such as circular or bit reversed addressing, and
specialized instructions to handle saturation and normalization. Interrupt handling
on DSPs is efficient and uncomplicated. Finally, some DSP families support high-
speed interprocessor communications which can directly link together multiple
DSP devices without any intervening logic. The complexity of integrating
external components with a processor is far higher for high performance GPPs
than it is with low-end GPPs and DSPs.
Testbed
In this subsection, we give our testbed architecture where a single camera node
is composed of a standard camera and a TriMedia video processing board.
Designed for media processing, the TriMedia processing board allows Windows
and Macintosh platforms to take advantage of the TriMedia processor via PCI
interface. Multiple TriMedia processing boards can be installed to one host PC
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