rivet - Register / Instruction Visualizer and Explainer Tool

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Table of contents

• Table of contents
• Introduction
• Requirements
• Usage
• Options
• Examples
  • config.json
  • dark.json
  • blueprint.json
  • transparent.json
• Config

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Introduction

This tool lets you generate visual explanations of binary instructions, or describe the contents of a register.

The layout and style can be customized to fit your needs.

For a full description of the schema format, please check out format.md

Requirements

• Python 3+
• Pygame - used to render the images
• Beautiful Soup 4 - used to parse XML files
• PyYAML - used to parse YAML files

Usage

Basic usage:

python3 main.py schema.xml

Directory mode + config:

python3 main.py -o out/ -c config.json -d schemas/

Options

Several command line options are available:

• -o PATH sets the output path. If not given, the output file will be located in the same directory as the input file, and given the same name (different extension)
• -d enables directory mode. If set, the input and output paths are directories and all files inside the input directory are processed
• -c PATH sets the config path. For more details on available config parameters, please read the Config section.

Examples

The following images were generated from this schema (example1.yaml):

Show / hide

structures:
  main:
    bits: 32
    ranges:
      31-28:
        name: cond
      27:
        name: 0
      26:
        name: 1
      25:
        name: I
      24:
        name: P
        description: pre / post indexing bit
        values:
          0: post, add offset after transfer
          1: pre, add offset before transfer
      23:
        name: U
        description: up / down bit
        values:
          0: down, subtract offset from base
          1: up, addition offset to base
      22:
        name: B
        description: byte / word bit
        values:
          0: transfer word quantity
          1: transfer byte quantity
      21:
        name: W
        description: write-back bit
        values:
          0: no write-back
          1: write address into base
      20:
        name: L
        description: load / store bit
        values:
          0: store to memory
          1: load from memory
      19-16:
        name: Rn
        description: base register
      15-12:
        name: Rd
        description: source / destination register
      11-0:
        name: offset
        depends-on: 25
        values:
          0:
            description: offset is an immediate value
            structure: immediateOffset
          1:
            description: offset is a register
            structure: registerOffset
  immediateOffset:
    bits: 12
    ranges:
      11-0:
        name: 12-bit immediate offset
        description: unsigned number
  registerOffset:
    bits: 12
    ranges:
      11-4:
        name: shift
        description: shift applied to Rm
      3-0:
        name: Rm
        description: offset register

config.json

dark.json

blueprint.json

transparent.json

Config

The config file may change the following values to customize the layout and style:

• defaultFontFamily: the default font family
• defaultFontSize: the default font size
• italicFontFamily: the italic font family (for value description)
• italicFontSize: the italic font size
• backgroundColor: the image background color (ex: [222, 250, 206])
• textColor: the default text color
• linkColor: the color of linking lines and arrows
• borderColor: the color of register borders
• bitWidth: the width of 1 bit (in pixels)
• bitHeight: the height of 1 bit (in pixels)
• descriptionMargin: the space between descriptions (in pixels)
• dashLength: the length of one dash (for dashed lines)
• dashSpace: the space between dashes (for dashed lines)
• arrowSize: the arrow size (height in pixels, width for horizontal arrow)
• margins: the margins from the borders of the image (in pixels, [top, right, bottom, left])
• arrowMargin: the margin between arrows and registers (in pixels)
• valuesGap: the gap between values (in pixels)
• arrowLabelDistance: the distance between arrows and their label (in pixels)
• forceDescsOnSide: if true, descriptions are placed on the side of the register, otherwise, they are placed as close as possible to the bit
• leftLabels: if true, descriptions are put on the left, otherwise, they default to the right hand side
• width: the image width (in pixels)
• height: the image height (in pixels)

Some config examples are already included:

• config.json: Default configuration values (black on white)
• dark.json: Dark theme (white on black)
• blueprint.json: Blueprint theme (white on blue)
• transparent.json: Transparent background, for easy integration in other documents (grey on transparent)