Using the PEP/7 Simulator

While studying Architecture, we are going to use some software provided by our CS Illuminated textbook. Be warned that this software has many more features than we will use (it was designed for a course entirely on computer architecture and operating systems). This guide is only a supplement to the treatment in the text. Please make sure that you have read Ch. 7.3-7.5 of the text.

  • Starting the software
    There are two ways for you to use the software associated with the textbook.

    1. If you are on the CC network and have the J: drive mapped as expected, I have placed a copy of this software there. You should be able to run the software from there if you'd like.

    2. If you are unable to regularly access the J: drive, or if you feel the software is running too sluggishly, you may choose to download a copy of the software and install it directly on your own machine. After doing that, you will not need to be connected to the CC network to run the software.

  • Setting convenient defaults

    I recommend doing the following immediately upon starting the software.

  • From the "Pep7" menu, select "Execution Input..." and select "Interactive Input from Keyboard."
  • By default, Pep7 will run the program from beginning to end without stopping. If you wish to have it go step-by-step through each instruction, you may go to the "Pep7" menu, select "Trace Options..." and check "Trace Program."

  • Using the software
    We will mostly rely on the "File" menu and the "Pep7" menu when using this simulator. The general use is as follows:

    1. You can either create a new file which you type from scratch, or you may "Open" an existing file.

    2. If you are dealing with code written in "Assembly Language" you must select the window containing such code and while that window is selected, choose "Assemble" from the "Pep7" menu. This results in the creation of a new window which contains the Machine Language representation of the original Assembly Language code (written in hexadecimal, one byte at a time).

      If you want to see more information on the translation from Assembly Language to Machine Language, select "Assembler Listing" from the "Pep7" menu.

    3. Once you have Machine Language code (either because it was originally entered that way, or because you assembled Assembly Language code), you must "Load" that code into the machine. Select the window containing the Machine Language code and while that window is selected, choose "Load" from the "Pep7" menu.

    4. Once you have loaded the machine code, you may start running the code by choosing "Execute" from the "Pep7" menu.

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