Assembling a Program

Table of Contents

• Introduction
• Exception Handler

Introduction

There are two toolbar actions used to assemble MIPS programs: Run→Assemble and Run→Assemble Folder. The difference between these actions is which source files are assembled. The Assemble action assembles only the currently selected file in the editor, whereas the Assemble Folder action assembles the currently selected file along with all other assembly files (extension .asm or .s) in the selected file’s parent directory. This behavior is somewhat primitive, but it is currently the only way to assemble multiple source files and “link” them in MARS Red.

Note that Assemble Folder will always place the text (program code) and data for the currently selected file first in memory. This can cause the entry point of your program to depend on which file was selected when assembling. To avoid this problem, it is recommended that multi-file projects define a global label main to specify the desired entry point for the program, which will be detected by MARS Red if the Settings→Use “main” as program entry point option is enabled.

Exception Handler

The Settings→Exception Handler dialog allows an optional exception handler file to be included in all assembly operations. Technically, the file is just added to the list of files given to the assembler, so it does not necessarily need to contain an exception handler; this is just the recommended use case for the feature.