The present invention relates generally to behavioral synthesis tools for creating integrated circuits, and more particularly relates to behavioral synthesis tools that allow for interactive interface allocation during the design of integrated circuits.
The design of complex computer hardware no longer begins with a circuit diagram. Instead, it begins with a software program that describes the behavior or functionality of a circuit. This software program is written in a hardware description language (HDL)(e.g. VHDL or Verilog) that defines an algorithm to be performed with limited implementation details. Designers direct behavioral synthesis tools to generate alternate architectures by modifying constraints (such as clock period, number and type of data path elements, and desired number of clock cycles). A simulation tool (e.g., Modelsim by Mentor Graphics) simulates the functionality of the system prior to generating a physical implementation of the circuit.
The HDL program is converted into a register transfer level (RTL) description. The RTL description is used to ultimately generate a netlist that includes a list of components in the circuit and the interconnections between the components. This netlist is used to create the physical integrated circuit.
Although describing a system design in HDL provides great flexibility to designers, it is desirable to provide a greater level of abstraction to describe the system functionality. For example, programming languages like C and C++ are now being used as a starting point to describe the function of a circuit. The description of the system in C or C++ is then used by synthesis tools to generate a HDL description of the circuit.
Unfortunately, certain aspects of the system's design cannot be described using conventional ANSI C and C++. For example, C and C++ cannot be used to describe hardware interfaces of the function, which are required to interact with the rest of the integrated circuit. Thus, a designer is forced to describe the functionality of a system design using C and then use HDL constructs to describe the interfaces. However, such a process is time consuming and costly.
Several attempts have been made to adapt conventional C and C++ to add the capability to describe interface components. For example, SystemC is an adaptation of C++ that adds the capability of describing interface elements. However, languages such as SystemC suffer from the same inefficiencies as other HDLs. For example, the programmer is forced to learn the specific language commands, which takes away the benefits of using a generic language such as C or C++.
Thus, there is a need for a tool that allows a designer to use a generic language, such as C or C++, but allows the designer to easily add hardware interfaces.
The present invention provides a behavioral synthesis tool that allows a designer to design an integrated circuit using a generic programming language, such as ANSI C or C++, without the need to include timing information into the source code. In one aspect, the source code is read into the behavioral synthesis tool and the user may dynamically allocate interface resources to the design. In another aspect, the dynamic allocation is accomplished through user input, such as a GUI, a command line, or a file. In another aspect, the behavioral synthesis tool automatically analyzes variables in the source code description and assigns the variables to interface resources. In yet another aspect, the variables and interface resources associated with the variables may be displayed in a hierarchical format in a GUI. In still another aspect, the GUI may allow for expanding and collapsing of different layers in the hierarchy. The GUI may also allow for drag-and-drop operations to modify the variable/interface resource allocation.
These and other aspects will become apparent from the following detailed description, which makes references to the accompanying drawings.
Turning briefly to
The interface resource library 68 may be designed in a wide variety of ways. An example is shown below having two parts: first, an I/O Hardware component is generated in RTL code; second, an interface describes the signals for communicating with the component.
Interface Library (Internal Format):
Hardware component in RTL (VHDL):
Having illustrated and described the principles of the illustrated embodiments, it will be apparent to those skilled in the art that the embodiments can be modified in arrangement and detail without departing from such principles.
For example, one skilled in the art will recognize that a non-array pointer can be mapped to a memory interface and an array pointer can be mapped to a non-memory interface. Additionally, a pointer to an array can be mapped to a memory interface.
Although the user input is described as coming from a command line, GUI, or file, those skilled in the art also understand that other user input techniques may be used. For example, the source code may be annotated through the use of pragmas or other means. For example, the source file could be annotated with a pragma such as:
Although the source code description is described without timing information, timing information may also be included in the source code in certain embodiments.
In view of the many possible embodiments, it will be recognized that the illustrated embodiments include only examples and should not be taken as a limitation on the scope of the invention. Rather, the invention is defined by the following claims. I therefore claim as the invention all such embodiments that come within the scope of these claims.
This application is a continuation-in-part of U.S. patent application Ser. No. 09/839,376, filed Apr. 20, 2001 now U.S. Pat. No. 6,611,952, which claims priority to U.S. Provisional Patent application No. 60/257,923, filed Dec. 21, 2000.
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Number | Date | Country | |
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Parent | 09839376 | Apr 2001 | US |
Child | 10313775 | US |