Mentor Graphics Corporation

Other

Luc M Burgun

Frederic Reblewski

Olivier Lepape

Alain Raynaud

Frederic Maxime Emirian

Register transfer level (RTL) source code is synthesized to generate a gate-level representation and to generate instrumentation logic corresponding to one or more statements in the RTL source code. The instrumentation logic comprises logic circuitry in addition to that of the gate-level representation. The instrumentation logic indicates an execution status for the corresponding RTL statement(s) during gate-level simulation.

Method and apparatus for gate-level simulation of synthesized register transfer level design with source-level debugging

An apparatus is programmed to automatically remove timing hazards from a circuit design. The apparatus identifies certain level sensitive storage circuit elements in the circuit design. The identified level sensitive storage circuit elements are those having timing hazards. The timing hazards arise as a result of potential skews between the reference signal for the circuit design and the synchronization signal controlling each storage circuit element. A skew, introduced by a gated or divided clock, cannot be assured to be within a design tolerance limit. Therefore, the program enables the apparatus to transform the identified level sensitive storage circuit elements into level sensitive storage circuit elements controlled by synchronization signals that do not have potential skews with respect to the reference signal of the circuit design. The transformation, however, is accomplished without altering the functionality of the circuit design. In effect, the apparatus automatically removes some or all of the timing hazards by determining the appropriate transformation for each of the identified level sensitive storage circuit elements.

Method and apparatus for removing timing hazards in a circuit design

Methods of instrumenting synthesizable source code to enable debugging support akin to high-level language programming environments for gate-level simulation are provided. One method of facilitating gate level simulation includes generating cross-reference instrumentation data including instrumentation logic indicative of an execution status of at least one synthesizable register transfer level (RTL) source code statement. A gate-level netlist is synthesized from the source code. Evaluation of the instrumentation logic during simulation of the gate-level netlist facilitates simulation by indicating the execution status of a corresponding source code statement. One method results in a modified gatelevel netlist to generate instrumentation signals corresponding to synthesizable statements within the source code. This may be accomplished by modifying the source code or by generating the modified gate-level netlist as if the source code was modified during synthesis. Alternatively, cross-reference instrumentation data including instrumentation logic can be generated without modifying the gate-level design. The instrumentation logic indicates the execution status of a corresponding cross-referenced synthesizable statement. An execution count of a cross-referenced synthesizable statement can be incremented when the corresponding instrumentation signals indicates the statement is active to determine source code coverage. Source code statements can be highlighted when active for visually tracing execution paths. For breakpoint simulation, a breakpoint can be set at a selected source code statement. The corresponding instrumentation logic from the cross-reference instrumentation data is implemented as a simulation breakpoint. The simulation is halted at a simulation cycle where the values of the instrumentation signals indicate that the source code statement is active.

Method and apparatus for gate-level simulation of synthesized register transfer level designs with source-level debugging

A computer system is programmed with logic for automatically removing timing hazards from a circuit design. More specifically, the computer system is programmed with logic for automatically detecting and resolving clock gating as well as clock division timing hazards from the circuit design. In one embodiment, the computer system is further programmed with logic for logically organize timing hazards into levels, after the clock gating timing hazards have been resolved, and then resolving clock division timing hazards recursively. In one adaptation, the computer system is a component of a hardware emulation system.

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Creteil, France

Luc M Burgun