Development of an application and hardware kernels targeting an FPGA requires a phased development approach. Because FPGA are programmable devices, building the device binary for hardware takes some time. To enable quicker iterations without having to go through the full hardware compilation flow, the AMD Vitis™ tool provides hardware emulation target to perform co-simulation of the software application and PL kernels. Compiling for hardware emulation is significantly faster than compiling for the actual hardware. Additionally, hardware emulation target provides full visibility into the application or accelerator, thus making it easier to perform debugging. Once your design passes in hardware emulation, then in the late stages of development you can compile and run the application on the hardware platform.
The Vitis tool provides following emulation target:
- Hardware emulation (hw_emu)
- The host program runs natively on x86, but the kernel code is compiled into an RTL behavioral model which is run in the AMD Vivado™ simulator or other supported third-party simulators. This build and run loop takes longer but provides a cycle-accurate view of kernel logic.
Compiling and linking for emulation is seamlessly integrated into the Vitis command line and IDE flows. You can compile your host and kernel source code for hardware emulation target, without making any change to the source code. For your host code, you do not need to compile differently for emulation as the same host executable can be used in emulation. Hardware emulation target support most of the features including XRT APIs, buffer transfer, platform memory SP tags, kernel-to-kernel connections, etc. The following sections detail the features and requirements of the hardware emulation flow.
While running emulation you can specify a number of trace options as described in Enabling Profiling in Your Application to capture design data during runtime. Any reports generated during the run are collected into the xrt.run_summary file. This collection of reports can be viewed by opening the run_summary in Vitis analyzer, and includes a Summary report, System and Platform Diagrams to illustrate the hardware design, Run Guidance offering any suggestions for improving the performance of the system, and a Profile Summary and Timeline Trace when enabled in the xrt.ini file during runtime. Refer to Working with the Analysis View (Vitis Analyzer) in the Vitis Reference Guide (UG1702) for additional information.
Installing the x86 XRT automatically sets the LD_LIBARY_PATH variable to point to XRT libraries.