GHDL

The open-source VHDL simulator.

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Overview

GHDL is a leading open-source simulator for the VHDL language. It functions as a compiler, analyzing and elaborating VHDL source files to generate a machine code model of the design. This compiled approach results in very fast simulation speeds. GHDL aims for full compliance with VHDL standards and is a popular choice in both hobbyist and professional environments for VHDL-based verification.

✨ Key Features

  • VHDL standards compliance (VHDL-87, -93, -2002, -2008)
  • High-performance compiled-code simulation
  • Works with VUnit and Cocotb for testbench automation
  • Can be used as a synthesis front-end for Yosys (via plugin)
  • Waveform generation (VCD, GHW formats)
  • Free and open source

🎯 Key Differentiators

  • Completely free and open source with strong VHDL standards compliance
  • High simulation performance due to its compiled nature
  • Strong integration with other open-source tools and frameworks

Unique Value: Provides a no-cost, high-performance, and standards-compliant VHDL simulator, enabling robust verification for everyone from students to professionals.

🎯 Use Cases (5)

Functional simulation of VHDL designs Automated regression testing in CI/CD pipelines VHDL language standards compliance checking Academic and educational use for teaching VHDL Open-source synthesis of VHDL designs

✅ Best For

  • Verification of open-source VHDL IP cores
  • Used as the simulation backend for VHDL verification frameworks like VUnit

💡 Check With Vendor

Verify these considerations match your specific requirements:

  • Verilog or SystemVerilog designs (GHDL is VHDL-only)
  • Users who require a full graphical IDE and debugger

🏆 Alternatives

Siemens ModelSim/Questa Aldec Active-HDL/Riviera-PRO Verilator (for Verilog)

Offers significantly better performance and VHDL-2008 support compared to other open-source VHDL simulators, and provides a free alternative to expensive commercial tools for VHDL-centric workflows.

💻 Platforms

Desktop (Linux, Windows, macOS)

✅ Offline Mode Available

🔌 Integrations

VUnit Cocotb Yosys (via ghdl-yosys-plugin) GTKWave (for waveform viewing)

🛟 Support Options

  • ✓ Live Chat

💰 Pricing

Contact for pricing
Free Tier Available

Free tier: GHDL is completely free and open source.

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