ModelSim supports Code Coverage (it is included in ModelSim SE, and an option to other versions of ModelSim). Questa supports assertion-based verification (including a library of pre-written assertions called Questa Verification Library or QVL, and an assertion thread debugger), automated test stimulus generation via a constraint solver engine, and PowerAware RTL verification supporting both CPF and UPF formats. ModelSim does not support any advanced verification features. Questa supports all of this and the C debugger and transaction viewing for SystemC and SystemVerilog are standard parts of the product. ModelSim supports an HDL editor, integrated project manager, source code templates and wizards, interactive and post-simulation debug, dataflow graphical and textual causality traceback, source annotation, memory window, extra standalone viewer, multiple waveform windows, waveform compare, C Debugger and transaction viewing for SystemC. Questa’s simulation support is identical to ModelSim’s ModelSim supports a single-kernel simulation engine, Verilog RTL & gate level performance optimizations, VHDL RTL & VITAL performance optimizations, performance and memory profiler, separate elaboration, waveform management tool set, VCD and extended VCD support, VCD re-simulation, batch mode simulation, integrated simulation, checkpoint & restore, Questa supports all of this as well as SystemVerilog IEEE 1800 for Verification, mixed language licensing (Questa is by default language neutral), PSL IEEE 1850, and SystemC 2.2 IEEE 1666/OSCI 2.2 as standard features. ModelSim supports SystemVerilog IEEE 1800 for Design only, as well as VHDL (1987, 1993, 2002), Verilog (1995, 2001, 2005), as well as options for mixed language and language neutral licensing and support for SystemC 2.2 IEEE 1666/OSCI 2.2. Questa is Mentor Graphics advanced verification platform that uses ModelSim as its core simulation engine.įeatures of the two tools can be grouped into five categories and compared as follows: ModelSim is Mentor Graphics HDL simulator. Though both are simulators from the Mentor Graphics there are some differences between them. We have captured some difference between Questa and Modelsim. We have seen people who are using modelsim / Questa simulator from Mentors but dont really know the exact difference between them. These are the industry popular and well proven simulators. At present time we are frequently using modelsim/Questa and vcs. We as an ASIC Engineer are frequently using different simulators for our simulation activity.

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