Compilation of Emulated Entities

This section describes how an emulated entity can be compiled into a format suitable for use in the co-simulation.

We use a running example here for the binary $HOME/Titan/scripts/x86_vt_spinner/x86_vt_spinner.c The goal is to make this code suitable for co-simulation.

Figure 1. All steps involved in compilation and lookahead extraction.

Figure 1 outlines all the phases involved in instrumenting executables and extracting lookahead from them. A tool called ttn is provided to help with these steps. The general worklfow is described below.

Step-0: Pre-compilation

Before compilation of a piece of emulated code, a titan project needs to be created for that code. This project needs to be unique for each distinct executable that needs to be co-simulated.

• Creating a titan project can be accomplished with the following command:

  ttn add -p <project_name> -s <project_source_dir> [additional options]
  

  For e.g, to associate the example binary with a titan project with the name “vt_test”, the following command needs to be used:

  ttn add -p vt_test -s ${HOME}/Titan/scripts/x86_vt_spinner
  

  Additional options may be used to configure the project at the time of creation. For e.g, to configure the project “vt_test” to use the “Skylake” target micro-architecture and a 2.7 GHz target processor, the following command needs to be used:

  ttn add -p vt_test -s ${HOME}/Titan/scripts/x86_vt_spinner -a Skylake --cpu_mhz 2700
  

  To see the list of supported options, use the command:

  ttn help
  

  To view the list of supported target micro-architectures, use the command:

  vtins -l
  

• To check the ttn project parameters, use the following command:

  ttn show -p vt_test
  

• To listing all created projects, use the following command:

  ttn list
  

• Activating created project. The next pre-compilation step is activating the project:

  ttn activate -p vt_test
  

  Ensure that the desired project is active before compiling its source files.

Step-1 Compiling a project source

• Go to the project source directory. In this example:

  cd ~/Titan/scripts/x86_vt_spinner
  

• Compile using clang with two additional flags -O1 and -lvtllogic

  clang -O1 -lvtllogic x86_vt_spinner.c -o x86_vt_spinner

  This step automatically figures out the current active project (in this case it is vt_test) and reads its parameters. The generated binary is instrumented according to the passed project configuration.

Step-2 Extracting lookahead from a compiled project

• To extract and store lookahead information, first ensure that DISABLE_LOOKAHEAD build flag in ~/Titan/CONFIG is set to no.

• Assuming the previous two steps have been completed, to extract lookahead use the following command:

  ttn extract -p <project_name>
  

  In this example:

  ttn extract -p vt_test
  

Step-3 Running the instrumented executable

To run the instrumented application as a part of a co-simulated model, some additional steps need to be performed. Instructions for launching co-simulations are described in detail here.

Updating a ttn project

To update a project, simply add it again:

ttn add -p <project_name> -s <project_src_dir> [additional options]

Deleting a ttn project

Use the following commands to deactivate and delete ttn projects:

ttn deactivate -p <project_name>
ttn delete -p <project_name>