CS252 Course Wiki: Spring 2012 Sections 1 and 2 : Tools browse

Logicly

Here is a flash-based gate simulator perfect for playing with and visualizing simple logic gates: Logicly

LC-3 Information

LC-3 Instruction Set on One Page (with ASCII character table on page 2): PDF or Word
Example code:
- LC-3 Chapter 5 Example 1 as a script (in txt) or alternatively instruction (in assembly) and data (in hex) files.
- LC-3 Chapter 5 Example 2 instruction (in binary) and data (in hex) files.

PennSim

The PennSim LC-3 Simulator can be run on any computer with Java 1.5 installed. Please see the PennSim Guide below for more information.

Running PennSim
- In Windows platform, you just double click on PennSim.jar
- In Linux, you have to type java -jar PennSim.jar in the command prompt
PennSim Guide
PennSim Software
PennSim Manual
PennSim's lc3 OS

File Types

You will encounter at least two filetypes when using PennSim:

.OBJ

These files are the "machine" code that can be loaded and executed by PennSim. It contains sequences of 16-bit binary values that correspond to LC-3 instructions. These files are unreadable in a text editor and will be created for you by PennSim's assembler function.

.ASM

These files contain LC-3 assembly code. Each line contains a single assembly instruction. For example, ADD R0, R0, #1 is a single assembly instruction. In order to convert a .asm file into a .obj file, it must be run through an assembler. This should be done through PennSim and is discussed in the PennSim Guide.

Creating .ASM Files

You may use any basic file editor that you would like to create .asm files. Be sure to save the file with a .asm file extension. Many text editors default to .txt, which will not work with PennSim. Here are some text editors that may work well:

   1. Windows: Notepad, Notepad++, LC-3 Edit (see below)
   2. Mac: TextEdit, TextWrangler
   3. Linux: gedit
   4. Any: vi, emacs

LC-3 Edit OPTION for Dealing with Binary/Hex Code

PennSim allows you to:

crudely load programs (as in the script above for Chapter5's Example 1) or
assemble and load programs (which will make more sense after Chapter 7).

In the interim, the Windows-only LC-3 Edit utility lets you to write binary/hexadecimal LC-3 code and convert it directly into an object file readable by PennSim. It is a self contained executable and does not require any installation. Use of L3-edit is OPTIONAL. It requires some learning and then can save some time (if you use Windows).