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86 lines
4.8 KiB
HTML
86 lines
4.8 KiB
HTML
<html>
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<title>MARS 4.5 help contents
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<body>
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<h3>MARS - Mips Assembly and Runtime Simulator</h3>
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<h4>Release 4.5</h4>
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<h4>August 2014</h4>
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<h4>Using MARS through its Integrated Development Environment (IDE)</h4>
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The IDE is invoked when MARS is run with no command arguments, e.g. <tt>java -jar mars.jar</tt>.
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It may also be launched from a graphical interface by double-clicking the <tt>mars.jar</tt> icon
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that represents this executable JAR file.
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The IDE provides basic editing, assembling and execution capabilities. Hopefully it
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is intuitive to use. Here are comments on some features.
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<ul>
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<li><b>Menus and Toolbar</b>: Most menu items have equivalent toolbar icons.
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If the function of a toolbar icon is not obvious, just hover the mouse over it and
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a tool tip will soon appear. Nearly all menu items also have keyboard shortcuts.
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Any menu item not appropriate in a given situation is disabled.</li>
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<li><b>Editor</b>: MARS includes two integrated text editors. The default editor, new
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in Release 4.0, features syntax-aware color highlighting of most MIPS language elements
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and popup instruction guides. The original, generic, text editor without these features
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is still available and can be selected in the Editor Settings dialog. It supports a single
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font which can be modified in the Editor Settings dialog.
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The bottom border of either editor includes the cursor line
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and column position and there is a checkbox to display line numbers.
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They are displayed outside the editing area. If you use an external editor, MARS provides
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a convenience setting that will automatically assemble a file as soon as it is opened. See
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the Settings menu.
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<li><b>Message Areas</b>: There are two tabbed message areas at the
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bottom of the screen. The <i>Run I/O</i> tab is used at runtime for
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displaying console output and entering console input as program execution progresses.
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You have the option of entering console input into a pop-up dialog then echoes to the message area.
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The <i>MARS Messages</i> tab is used for other messages such as assembly or
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runtime errors and informational messages. You can click on assembly error messages to
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select the corresponding line of code in the editor.
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<li><b>MIPS Registers</b>: MIPS registers are displayed at all times, even
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when you are editing and not running a program. While writing your program,
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this serves as a useful reference for register names and their conventional
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uses (hover mouse over the register name to see tool tips). There are three
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register tabs: the Register File (integer registers $0 through $31 plus LO,
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HI and the Program Counter), selected Coprocesor 0 registers (exceptions and
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interrupts), and Coprocessor 1 floating point registers.
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<li><b>Assembly</b>: Select <i>Assemble</i> from the <i>Run</i> menu or the
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corresponding toolbar icon to assemble the file currently in the Edit tab.
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Prior to Release 3.1, only one file could be assembled and run at a time.
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Releases 3.1 and later provide a primitive Project capability. To use it, go to the
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<i>Settings</i> menu and check <i>Assemble operation applies to all
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files in current directory.</i> Subsequently, the assembler will assemble
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the current file as the "main" program and also assemble all other assembly
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files (*.asm; *.s)
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in the same directory. The results are linked and if all these
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operations were successful the program can be executed. Labels that are
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declared global with the ".globl" directive may be referenced in any of the
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other files in the project. There is also a setting that permits
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automatic loading and assembly of a selected exception handler file. MARS uses
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the MIPS32 starting address for exception handlers: 0x80000180.
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<li><b>Execution</b>: Once a MIPS program successfully assembles, the
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registers are initialized and three windows
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in the Execute tab are filled: <i>Text Segment</i>, <i>Data Segment</i>,
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and <i>Program Labels</i>. The major execution-time features are described below.
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<li><b>Labels Window</b>: Display of the Labels window (symbol table) is
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controlled through the Settings menu. When displayed, you can click on any label
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or its associated address to center and highlight the contents of that address
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in the Text Segment window or Data Segment window as appropriate.
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</ul>
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<p>The assembler and simulator are invoked from the IDE
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when you select the <i>Assemble</i>, <i>Go</i>,
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or <i>Step</i> operations from the <i>Run</i> menu or their corresponding
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toolbar icons or keyboard shortcuts. MARS messages are displayed on the
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<i>MARS Messages</i> tab of the message area at the bottom of the screen.
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Runtime console input and output is handled in the <i>Run I/O</i> tab.
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<p>
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<hr>
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<p>
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This document is available for printing on the MARS home page
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<tt><b>http://www.cs.missouristate.edu/MARS/</b></tt>.
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</body>
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</html> |