CMPUT 229 - Computer Organization and Architecture I

Examples of Code Patterns and Structure in RISC-V

This resource provides patterns for RISC-V assembly beginners along with explanations that allow the combination of different structures that can be used to write useful programs in RISC-V assembly.

These files are meant to be suggestions or aids, not rules and laws. This is not the only way to solve the programming problems illustrated but it can help you get started.

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Contents

The links in this overview take you to the appropriate sections; feel free to skip to what you need now.

1. Elements and structure of a RISC-V file assembly program.

   • Labels and Sections: Introduces labels and the data/text sections.
   • Data Section Directives: Summary of common data section directives.
   • System Calls: Summary of system calls and common ones you may need to use.
   • Coding Style: Covers some suggestions for good style.

2. Function structure.

   • Basic Subroutines: Introduces basic leaf functions.
   • Argument and Return Values: Covers a simple way of passing args between functions.
     Note that this example ignores register calling conventions, which will be expected later in the course.
   • Main Function: Introduces the main function.

3. Conditional statements.

   • If: Introduces a basic if conditional.
   • If/Else: Introduces an if with an unconditional else block.
   • If/Elif/Else: Introduces an if, with conditional elif blocks and finally an unconditional else block.

4. Creating loops.

   • Do-While Loop: Covers the structure of a do-while loop.
   • While Loop: Covers the structure of a while loop.
   • For Loop: Covers the structure of a for loop.

5. RISC-V Dot Graph Generator: A Call-Graph Display for RISC-V Assembly

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Acknowledgement

• Many examples were built upon those found in MIPSPatterns, created by Braedy Kuzma, which contains many of the code snippets and explanations for MIPS assembly.