Behavioral transformations

This chapto describes the transformations that are performed at the behav-icnal level in Hocules. Behavioral transformations identify the inherent inter-opmtion parallelism in the behavior. Understanding the parallelism can give an indication of the fastest design synthesis can produce, assuming in the final implementation each q)eration is implemented by a dedicated hardware component While this assumption may not be realistic due to area and interconnection limits, computing the performance under this assumption is important as a bound on the given behavior. 

This chapter is organized as follows. Section 3.1 describes the BIF model. Sections 3.2 and 3.3 present the user-driven and automatic behavioral transformations, respectively. Finally, Section 3.4 summarizes the behavioral transformations applied in Hercules. 

The first phase of SUGAR translates the source description to an internal representation and applies transformations to prepare the behavior for hardware allocation. This section describes the behavioral representations and the transformations defined on them. 

In ISPS, application dependent information can be attached to any part of the description using qualifiers — lists of arbitrary attributes, with each attribute having an optional value. Qualifiers are not interpreted by the ISPS compiler instead, their interpretation is left to the application. For example, a qualifier, (time 100), may be attached to a loop to imply a maximum loop time of 100 time units. A specific application program may interpret this as a requirement that must be met. 

Qualifiers are used to pass important information to SUGAR. The qualifiers fall into 3 categories  

Qualifiers required to describe the bus controller for memory accesses. SUGAR does not synthesize the bus controller. Instead, memory accesses are described by ISPS procedures tagged with qualifiers. 

Qualifiers which suggest useful hints for good synthesis of microprocessors. Examples are identification of ISPS procedures as instructions or effective address routines. 

---

Radicals are employed widely in the polymer industry, where their chain-propagating behavior transforms vinyl monomers into polymers and copolymers. The mechanism of addition polymeri2ation involves all three types of reactions discussed above, ie, initiation, propagation by addition to carbon—carbon double bonds, and termination ... 

Almost any organization of any size is filled with its own tales of theory X and theory Y. The next section considers one true story in which an employee s behavior transformed dramatically with a change in management. 

Unsafe operation is the abnormal behavior that conflicts with the psychological characteristics of people. Behavior which has caused or may cause accident must be an unsafe behavior during production activities. Once unsafe behavior in a person s life does not necessarily occur, it causes harm. Often unsafe actions, however, definitely lead to accidents. Even though the objects are the main reason for the accident, it also can t rule out human wrong behavior transformation hidden behind the unsafe state. Simply speaking, unsafe behavior has the following characteristics. 

As already mentioned earlier, the combustion engine control algorithm is an excellent test vehicle for behavioral transformations, especially since the background memory is both complex and intricate. The initial HardwareC specification uses 37 arrays of 128 float values each. After background memory... 

Supports behavioral transformations, primarily to improve the efficiency of the control structure constant folding, common subexpression elimination, dead procedure elimination, inline expansion and formation of procedures, code motion into and out of the branches of decoding operations, and loop unrolling. 

Robert A. Walker and Donald E. Thomas, "Behavioral Transformation for Algorithmic Level IC Design , IEEE Trans, on CAD, pages 1115 1128, October 1989. 

Robert Allen Walker, Design Representation and Behavioral Transformation for Algorithmic Level Integrated Circuit Design, PhD Thesis, Dept, of Electrical and Computer Engineering, Carnegie Mellon University, April 1988. 

The Behavioral Transformations tool provides a means to transform the original behavioral description. These transformations make the behavior more appropriate for implementation and provide the basis for exploring the design space at the Algorithmic Level of design. 

The SUGAR style-specific microprocessor designer includes both behavioral transformation and Register-Transfer Level synthesis functions. 

Behavioral transformations were run on the System/370 VT to eliminate unnecessary operators, combine SELECT operators where possible, and inline expand any vtbodies that are only called once. This resulted in one large vtbody containing the gist of the instructions, and a number of smaller vtbodies containing auxiliary functions. 

During initialization, EMUCS gathers the information that it needs in order to produce a data path. The user may choose to have EMUCS operate on a complete description, or on individual processes, as determined by behavioral transformations (see Chapter 3). The initialization phase gathers only the information needed for the process specified by the user. 

Snow [Snow78] defined several behavioral transformations to reduce the biases inherent in algorithmic languages and showed that the transformations can have a significant effect on the quality of... 

Behavioral Transforms none 2 horizontal processes 2 vertical processes none none... 

Behavioral transformations were run on 4 of the Elliptical Filter designs to create multiple process designs. Ultimately, the RT designs... 

As stated earlier, these results (reduction in per-process area or microcode) are not guaranteed to occur for all designs, or for all process divisions. However, the idea that the per-process area and the number of values shared between processes can be varied with different process formations follows our intuition. The Workbench, with its behavioral transformations, provides a computer-aided environment in which to explore such alternatives. 

Overall, the Elliptical Filter shows how the first two tools in the general synthesis path can be used to explore the system level design space. The utility of behavioral transformations in exploring various... 

The initial ISPS description of the 6502 is highly modular, containing many vtbodies, many CALLs, and three levels of instruction decoding. This makes the description easily readable, but difficult to synthesize well, so behavioral transformations are appropriate. 

Pipelines can be created for this design using further behavioral transformations two variations are presented here. The first alternative is illustrated on the left side of Figure 8-10. In this alternative, the design was partitioned into a 4-stage pipeline, with... 

The following outline shows how behavioral transformations can be used to create design C, a four pipestage description, from the unpipelined description. The four stages for this design are IFETCH, DECODE, OPFETCH, and EXECUTE. 

Design Representation and Behavioral Transformation for Algorithmic Level Integrated Circuit Design. 

---