Xputers: FQA (3):
Xputers: FQA (2)
Xputers and Hardware/Software Co-Design
Xputers and Custom Computing Machines
Xputers and Application-specific Processors
Xputers and ASIPs
The Xputer: more than just a General Purpose Accelerator
Call for Partners - New Horizons in R&D
Forthcoming Books on Xputers
Hardware/Software Co-Design  has the goal to optimize the hardware/software trade-off in Partitioning an application problem into a software part (to run on the host) and an add-on accelerator hardware part. Researchers complaint  that a general model is missing, which brings the very wide variety of architectures under a common umbrella. The Xputer paradigm has the potential to be such a general model of hardware/software co-design (see here).
The design of custom computing machines 
 is similar to hardware/software co-design.
The main difference is the use of fied-rgramabe ccelerators, whereas hardware/software
co-design prefers hardwired add-om accelerators. Also here the Xputer paradigm
has the potential to be a general model of hardware/software co-design
which bridges the many gaps between the very wide variety of architectures.
For implementing Application-specific accelerators a hardware experts
are needed, even for FPGA-based custom somputing machines. Compilers accepting
programming languages are not available for synthesis, so that these ommercially
available platforms are far from the dream of software-only implementation
of accelerators. The ASIP approach redesigns everything (see next section),
even compiler and operating system are application-specific - a huge effort,
as long as a very powerful repertory of generators is not available. Custom
computing machines  
are a tinker toy approach not permitting a systematic compilation environment.
What we need are general purpose accelerators - technology platforms suitable
for being supported by a novel class of application development tools.
compilation techniques. The key issue on the way to implementation 
of accelerators are general purpose compilation techniques instead of specialized
compilers. We believe, that Xputer-based platform architectures are the
best basis of general purpose compilers for software-only accelerator implementation.
ASIPs (Application-specific Instruction Set Processors 
 ) are developped by experimenting with alternative
processor architectures for particular application samples. Their alternative
perfornce data are derived by profiling from simulation. Each alternative
requires a complete processor design, so that there is no compatibility
to existing software of any kind. That's why an ASIP development environment
should have a bunch of generators like an architecture generator, a compiler
generator, operating system generator, and a simulator generator. Also
Processors and Xputers
Xputers provide high speed-up factors for all applications with halfways
or fully regular data depencencies, such as in DSP, image processing, most
scientific applications and many others. For more details see section FQA
The Xputer may also be used in stand-alone mode. E. g. this makes sense
in embedded systems and in many other eapplication environments with high
cost/performance trade-off requirements. Xputers are used as central units,
the CPUs. This means an accelerator without a host: really a full paradigm
switch. Also see software-only
The usual add-one hardware provides speed-up by software to hardware migration. In addition to his Xputers provide further speed-up by runtime to compile time migration (RT2CT migration). This is shown by comparative overhead analysis. An example is comples address computation (see fig. 26), which ona vonNeumann implementation has to be carried out at run time, whereas on an Xputer this may be done by compiling reconfiguration code to be downloaded into a data sequencer. In a grid-based design rule check implementation, for example, this has contributed one and half order of magnitude to speed-up (see fig. 26).
Xputers: FAQ (2)
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