.. _FAQ:

Frequently Asked Questions
==================================

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    **How is LegUp different from other high-level synthesis (HLS) tools?**
       LegUp is also the only HLS tool that supports the use of Pthreads and OpenMP to
       create parallel hardware. This powerful feature allows one to write standard multi-threaded software,
       and automatically compile it to a multi-core hardware system. Lastly, LegUp can
       generate a complete SoC, comprising a processor and hardware accelerators, with a click of a single button.
    **Tell me more about Pthreads and OpenMP support.**
       Pthreads and OpenMP are popular parallel programming methodologies in software.
       The threads described in software gets compiled to execute on multiple processor cores.
       LegUp can take the same software program and automatically compile it to multiple hardware cores.
       This powerful technique allows one to create a multi-core hardware system directly from software, without any changes to the code.
       This feature is available both for a hardware-only system (without a processor) or for a processor-accelerator hybrid system.
    **Tell me more about the processor-accelerator hybrid flow.**
       Not all programs are amenable for hardware acceleration. One may want to have a processor for controlling the hardware, or
       to run an operating system, or just for ease-of-use. The processor-accelerator hybrid flow in LegUp allows one to accelerate a portion of the program while keeping the rest running in software on a processor.
       All that the user has to do is simply designate which function(s) to accelerate in hardware, and the rest is taken care of automatically.
       LegUp automatically partitions the program so that the designated function(s) and the descendant functions are compiled to
       hardware accelerators, with the remainder of the program is compiled to execute on an ARM processor.
       The tool automatically handles the software/hardware partitioning, and their communication interfaces and interconnect are also automatically generated.
       This flow allows one to generate a complete SoC, comprising a processor and hardware accelerators, directly from software.

**What is the input software language to LegUp?**

  LegUp supports most of ANSI C and C++, but does not support recursive functions or dynamic memory. Also we do not support the STL C++ library (vector, map, set, etc.).

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  As mentioned above, LegUp also supports Pthreads and OpenMP to create parallel hardware.

**What is the generated RTL language?**

  Currently, LegUp only supports Verilog output.

**Which FPGAs do you support?**

  LegUp supports Microchip PolarFire FPGAs.

**How can I get support?**

  Please contact legup@microchip.com.